Gas station without pumps

2016 August 3

Possible new lab order

Filed under: Circuits course — gasstationwithoutpumps @ 12:09
Tags: ,

I’ve been thinking about how to rearrange the labs (and the textbook) for a more sensible 2-quarter sequence. I need to have the basics done before October, since that is when I have to tell the lab staff what tools and parts to order for the winter quarter class.

Currently, the first half of the course is mainly voltage dividers and device characterization, and the second half is mainly amplifiers, but I’m thinking of changing the split so that all the audio stuff (microphone, loudspeaker, preamp, class-D amplifier) are in the second half, moving some of the other amplifiers (pressure sensor instrumentation amp and optical pulse monitor) to the first half.

There are 20 95-minute lab sessions each quarter, which is about the same total time as the 20 3-hour sessions of the old design (splitting a 3-hour session into two sessions adds some setup and teardown overhead, so two 95-minute session is no more than one 3-hour session, and may actually give students less time).

Here is the tentative new lab order:

1 T get parts, one person solders headers, other identifies and sorts parts
2 Th partners swap roles.
3 T Thermistor resistance measurement (ohmmeter) ice water
4 Th Thermistor resistance measurement (ohmmeter) hot water
5 T Thermistor voltage measurement (calibration check & recording)
REPORT (recording thermometer design)
6 Th function generator, oscilloscope, and PteroDAQ for time-varying signals. This is a tools lab, and I’m not sure exactly what form it will take.
7 T Sampling and aliasing (fixed sampling freq, downsample, record 0.1, 0.2, 0.4, 0.45, 0.5, 0.55, 0.6, 0.8, 0.9, 1.0, 1.1, 1.45, 1.6, 2.1 times sampling freq)
8 Th Sampling and aliasing continued (fixed input frequency, adjusting sampling frequency)
REPORT (sampling and aliasing)
9 T hysteresis threshold measurements using PteroDAQ & slow function generator, using 2 methods:

  • plotting Out-vs-in (with lines)and
  • Trigger on rising, trigger on falling to get thresholds.

Maybe add noise generator + power-supply → PteroDAQ digital inputs with and without hysteresis, but inputs on Teensy LC and Teensy 3.1/3.2 already have 0.06*Vdd = 200mV of hysteresis—maybe 74HC14N vs 74HC04, using PteroDAQ to look at digital output?

10 Th hysteresis oscillator on breadboard, view waveform on oscilloscope
11 T solder hysteresis oscillators & show PteroDAQ recording of freq vs. time for touch sensor
REPORT (hysteresis and relaxation oscillator)
12 Th Pressure sensor and instrumentation amp (low gain)
13 T Pressure sensor and inst amp + 2nd-stage op amp
14 Th Recording blood pressure measurements
15 T Drilling holes and recording breath pressure
REPORT (pressure sensor and instrumentation amp)
16 Th LED I-vs-V, phototransistor I-vs-V (dark), phototransistor I-vs-V (room light).
Question: how to make dark be dark enough?
Should we do phototransistor I-vs-V for room light through fingers?
17 T first-stage transimpedance, set gain to avoid saturation with DC.
Should I introduce log-transimpedance amplifier? Better design, but probably too much for first op-amp lab.
18 Th first-stage transimpedance, measure AC signal
19 T add high-pass & second-stage
20 Th low-pass in transimpedance to reduce 60Hz interference? 3-stage amplifier?
REPORT (optical pulse monitor)
quarter break
21 T get new parts + Microphone I-vs-V DC characterization
22 Th Microphone I-vs-V DC characterization
23 T Loudspeaker impedance
24 Th Loudspeaker impedance
REPORT (audio transducers)
25 T Mic preamp first stage
26 Th Mic preamp second stage
27 T Mic preamp soldering
28 Th Mic preamp soldering
REPORT (Mic preamp)
29 T nFET + pFET Id-vs-Vgs, Ron-vs-Vgs ??
Doing this right for power FETs is harder than I initially thought, so we’ll probably have to skip it, unless I come up with some clever way to make it easy.
30 Th Class D power amp
31 T Class D power amp
32 Th Class D power amp
REPORT (Class-D power amp)
33 T Electrode impedance (stainless steel)
34 Th Electrode impedance (stainless steel)
35 T Electroplating Ag/Agcl
36 Th Electrode impedance (silver)
REPORT (electrode impedance)
37 T EKG
38 Th EKG
39 T EKG
40 Th EKG

I’m thinking that reports will be due either Friday (for labs that end on a Tuesday) or Monday (for labs that end on a Thursday), with the intent of grading the labs on the next weekend and returning them on the following Monday.  There are still 10 lab reports due, but they are now spread over two quarters, so only biweekly, rather than weekly.

I’d like hearing from people (particularly students who’ve taken the course) about the order for the labs, the time allotted here for each lab, and ideas for things to add or remove. If no one has any better ideas, I’ll start rearranging the chapters of the book this week.

2016 January 9

Student project ideas for freshman design seminar 2016

Filed under: freshman design seminar — gasstationwithoutpumps @ 20:06
Tags: ,

For the second assignment in the freshman design seminar for W 2016, I had students look on the web for ideas for projects they might want to do.  I had set up the theme as “thrift store science”: do-it-yourself lab equipment of quality suitable for middle school or high school labs (though not necessarily with the durability that school lab equipment usually needs), but students were not restricted to the theme.

I’ve collected here the ideas students submitted, in the order they were turned in. Only 9/13 of the class had them turned in on time—I worry about the other 4.  Two of them turned in theirs late (12 and 14 hours late), but the other two haven’t turned theirs in yet as this post is being published.

Perhaps I should make sure that the slow four pair up with each other for the projects, so that they don’t drag down the students who do their work on time.  I’m not a believer in pairing strong students with weak students, since that usually results in the strong student doing all the work (and hating group projects) and the weak student learning nothing other than how to shirk work—a life skill that they probably already have enough experience in.

There was a bit too heavy reliance this year on—although that site has a number of decent projects, the format restrictions of the site mean that a lot of the better projects never get submitted there, but appear on individual blogs, Arduino forums, or other specialized sites.  There is enough representation of these other sources that I don’t need to discuss search strategies in class for everyone, but those students who only looked at instructables probably need to improve their internet search skills.

I’ve added my own comments to a few of the ideas in green, otherwise the text is from the students.

Maroon comments were from students other than the one submitting the original project, due 2016 Jan 23.

Here is my list of project ideas:
– DIY heart beat sensor tutorial using an arduino board

Optical pulse monitors are a doable project for this course—several students did them last year, and they are a one-week lab in the Applied Electronics course. (This link does not work) This project I am extremely interested about. A pulse monitor is a project that will not be too time consuming, but will require hard work to complete. the cost of this project will not be too expensive as we would as arduino processor, which is not too expensive. I believe this project can help me learn about arduino more and could be an nice experience for me with sautering and programming. 

My second vote is for the hear beat monitor because of the skills it builds and the low cost of the project. The instructions seem to be fairly straightforward and also includes the arduino code. One question I have is if we can write the code ourselves or if it is at all possible to improve the code that is given. I don’t know if that is possible but just something i was hoping someone could clarify.

I think this would be a great project. It seems to be fairly simple yet it has components which would allow us to learn about several different concepts. Also the parts seem to be cheap which is perfect for a class project.

I think that this project is very popular with the class. It’s a great way to apply what we are learning. It covers a lot of things that we may see in the future. We do not have a lot of time but this project looks very possible. The design is already provided and it shouldn’t be too expensive to build. Given that only a few people in the class have some kind of previous experience or knowledge about electronics, it should not be too complicated for the others. The project is very interesting and can have various uses.

I actually have a heart rate monitor that is made for road/mountain biking and comes in the form of a strap that goes around the chest.  The hardest thing to do is actually pick up a signal from the pulse; sometimes mine even has trouble with this and its the same strap used in the pro peloton. Other than that I don’t think there is a whole lot of issues that would really take a lot of time to sort out. The timer would be relatively easy to program, once there is actually something to measure. Another decision to make is if the heart rate to be measured would be over a single rep or a specific amount of time. Very cool project though.

I think this would be a really enjoyable project to take part in. It provides a healthy balance between difficulty and feasibility, and I think it would definitely develop our engineering skills. I also agree that it would be within a very reasonable price range.

– DIY vacuum cleaner robot which roams around and vacs up everything in its path

This project looks a bit expensive ($60 with surplus parts, probably over $100 with new parts) and may require more shop tools than we have access to.

This project requires a lot of extra parts that would only be beneficial if the person is fully dedicated and willing to spend an extensive amount of money and time on it. It seems to be very interesting project, and something that would be doable over a longer period of time. It would be amazing if this project was done efficiently in the time given in this class.

– Automated DIY plantduino greenhouse with automated watering and temperature system

Only simple control of a plant watering system is actually included in this instructable, though temperature and light measurement are mentioned at the end (control of light and temperature is also mentioned, but with no discussion of how they are to be controlled—adding heat and light is fairly easy, but removing them is not).  A plant watering, heating, or lighting system is a doable project, though we can’t work with plumbing in the electronics lab.  

The mechanical construction in this design relied on building outside on the ground—we don’t have a protected space for such work, so the design would have to be modified to be portable.

Here is my list of potential projects:
– DIY design for an incubator using an arduino

Doable, and I have the styrofoam boxes needed to build this.  I’d recommend using a power resistor and a low-voltage, high-current power supply instead of a light bulb.  Not only is it safer, but a lot of cultures are sensitive to light.  Adding a small fan would help keep the temperatures more uniform throughout the box.  See the 10 posts I wrote on incubators as a possible project for the course (though WordPress insists on putting them in the order most-recent-first, which is backwards from the order they should be read in).

-DIY ultrasonic range finder similar to the ones marketed by parallax

This one is kind of cool.  I’ve used Ping))) and Maxbotix range finders, but not considered building my own.  The $1.25 transducers and a few bucks of analog parts would be enough (together with a microcontroller board).  Finding a data sheet for the Matsushita #0D24K2 transducer might be a bit tough, but several hobbyists have used them, so there may be enough data available (24.5kHz±0.5kHz, an unusual frequency for ultrasonic transducers).  But w can get the more common 40kHz TCT40-16R/T transducers for $1.25 a pair (or unsolder them from the 68¢ module, though that will leave tails too short for breadboarding).

This DIY ultrasonic range finder,, looks like a lot of good circuit building. I think this Range Finder should be designed to start running a second circuit that does something like flash an LED or play a song when someone is close to it.

I think this project would be perfectly doable. It also ties into the science lab equipment on a budget theme. It also can be put to many other applications once built. Perhaps a project extension could be designing this for a specific application, such as a car detection system? I would vote for this project just because of the perceived simplicity of it. The programming does not seem too intensive but I would like some help in finding out what the arduino coding actually means. Another advantage, besides the simplicity, would be that we could use it for another project if time was left at the end of the quarter.


List of possible projects:
-DIY pulse monitor, we can detect heart beats and be able to see it.

Optical pulse monitors are a doable project for this course—several students did them last year, and they are a one-week lab in the Applied Electronics course.

-Make your own activity tracker using an Arduino

This looks doable (other than making a case), and involves only programming and wiring, no electronics design.

-Make your own smart watch

This one seems to be mainly programming and a 3D-printed case also.

-DIY Livescribe, it’s still in progress but being able to create one for much cheaper would be really cool

A bit more challenging than the other projects, since converting accelerometer or accelerometer+gyroscope data into position data is not trivial.  Probably beyond the scope of a 2-unit course.

I had no idea what live scribe was until I saw this. I love this project. It looks very difficult however. I have no idea how complicated the programming would be to make a live scribe pen work. The hardware design would take a lot of time and may be expensive. 

This project does seem difficult. I think this would be a good attempt to actually create something instead of taking plans since this project isn’t exactly fleshed out. It would take a lot of thinking and design to get it to function properly. I’d like to attempt this one too.

Capacitance-Touch Arduino Keyboard

We can definitely do the capacitive touch sensing with the Teensy boards, as the chips are designed to have low-power capacitive touch sensor interfaces.  The Teensy boards also have real digital-to-analog conversion, so we can do better sound synthesis than just a square-wave buzzer (perhaps the Karplus-Strong plucked-string algorithm).

I think that this is a very possible project for the class. It looks fairly simple and wouldn’t require much spending. Given that we are on our 4th week and have not finished our first project, this one looks fairly simple to do. The materials are easy to find and seems to cover most of what we want to learn. Since the teensy boards are compatible with Arduino, that should’t be much of a problem. The instructables also already come with the code which may or not be a good thing depending on the situation, that is, it’s good to have it because of the time span but we may not necessarily learn how the code works unless we write it letter by letter. Other than that, it should be fun and doable for this class.

3D Touchless Tracking Interface

Another application of capacitive sensing—again this looks quite doable.

This seems like it’s a very interesting project to be working on, it seems likes it’s a cheap design and it can be very easily doable. I do have some question on what it’s applications would be but other than that I think it could be a very interesting project to try to do.

This one caught my eye immediately. I thought it would be difficult to manufacture but it seems to be very uncomplicated. The setup is very simple but the effect is profound. I would be very interested in this project.

9 DIY Basic Hardware Projects
(1) Power a non-usb powered gadget with a usb.
(2) Create battery powered usb charger.
(3) 3D-ize current hardware.
(4) Create a laser gun.
(8)Notebook picture frame. Moving picture frame.
None of these look much like design projects to me. They are consumer-product hacks for the most part.
Make your own wireless (pad) phone charger.
This looks like just “install premade boards”, with no design other than mechanical. has MANY arduino-related projects. On there are attached PDF data sheets and instructions.
Not a particularly useful pointer.  That’s like saying Wikipedia has lots of articles, or Google can be used to find things.
Arduino Nano: Infrared obstacle avoidance sensor with Visuino
Connecting an existing infrared proximity sensor to a microcontroller is pretty trivial.  Designing an infrared sensor might be a reasonable project, or coming up with a project that actually used the sensor for something useful.
Ive [sic] always wanted to try making a rage [sic] finder that used light rather than sound to collect data. The reasoning behind this is that light would give a much more accurate reading.  There wouldn’t be as much interface.  However I’m not sure if we could make something compact enough to be of any use. That may not be a concern for many but i [sic] want whatever we make have a pretty easy application to some other project.
I think that this comment goes with this project, though a range finder and a proximity sensor are very different devices. A time-of-flight range sensor is much easier with sound (at about 300m/s) than with light (at about 300 m/µs).
Arduino: Micro laser show with a CD lens mechanism. (Two dimensional laser show projector)
Mainly mechanical design, assuming that you can find a dead CD ROM or DVD drive to disassemble.
Arduino: How to control LED lights with a remote control.
This is a very straightforward project—perhaps a bit too simple for a 2-unit class.

Home Alarm System
Very simple light sensor.

This project seems to have all of the circuits and for the home security given which would lessen the originality of the project. Other than that the project is achievable. The project doesn’t seem to require much extra equipment which would be better than some of the other projects.

Water Level Detector

Very simple conductivity-based water sensor with logic gate to do OR.

Project Idea: Automated Greenhouse System (some of the parts, not all, will be automated)

Conductivity Probe(detects nutrients in soil)

The electronics and microcontroller program for a conductivity probe is a reasonable project for the class, but some thought would need to be given to the mechanical design of the probe itself.  This project is similar to, but slightly more ambitious than, the electrode lab in the Applied Electronics course.  The amount of water involved may be small enough that we could do the work (in secondary containment tubs) in the electronics lab.

LED Artificial Light Supply to Grow Plants
Although this particular instantiation is not very exciting, designing grow lights is a reasonable project.

This one is a little intensive but it comes in a kit “DIY Robot Arm”

A wooden version of the MeArm robot arm shown in the lifehacker post is available new for $40 on ebay, including 4 servo motors.  Building a kit is fun, and programming the arm would be educational, but the design would be limited to software, as the hardware has already been designed.

Intelligent lighting system for aquarium/terrarium
Controlling RGB lighting strips is a reasonable task, through we’d have to add a voltage regulator, since the Teensy boards run off 3.7V–5.5V, not up to 12V where the LED strips are designed to operate.  That makes the task just difficult enough to be interesting. 

A more  feasible project that caught my attention,  This would be much more simple but I would like to use this in a fish tank at home to experiment with plant Vs. algae growth. 

This seems like a very interesting project to take on. It seems like there are many components related to it and it would be quite interesting to see the different design that would come from this since there aren’t any provided in the guide. It could be used in many of schools and it seems simple and cheap enough to do. 

Simple automatic humidifier
The part this is based on (from Seeedstudio) is no longer available, but water atomizers are available from eBay for $7–$10, and hooking it up to a microcontroller and adding a humidity sensor would make this a reasonable project.

Digital thermometer (the title on the page is wrong)
A digital thermometer is the first assignment in the Applied Electronics class, so perhaps a bit too simple for this course.  But using it to make a digital thermostat (that is, adding control of a heater) would make it sufficiently challenging. I am very interested in this project. Although it seems a little simple, I believe it will be an exciting project especially with someone like who has had some experience with processors and programming. I have read some of the projects that the other classmates have posted and they seem a little too complicated and time consuming. I strongly believe this project will be great and fun. I have done some research and this project would not be too expensive, but would require hard work and commitment in order to be successful. 

This is a very interesting project, and could prove to be very rewarding. Not only is it very reasonable, but it also could prove to be an important device to build if we as students go on to build future projects that involve temperature sensors. Also, once again this project seems to fit into a very reasonable price range.

LED Cube
A decent construction and programming project, without much electronics design.

B—— also mentioned his interest in this project and I also have interest in this project. Since we are learning about LEDs, it could be a good idea to demonstrate to Kevin what we have learned in the quarter by involving LEDs in our final project. This project illuminates the three different colors in a RBG LED. We can adjust this project by making a LED cube to make the project a little more difficult. Again, I think this will still be a good final project.

(I’ve counted this as a comment on the RGB LED cube, though it is apparently an attempt to introduce a new project to the list.)

Arduino Thermometer
A digital thermometer is the first assignment in the Applied Electronics class, so perhaps a bit too simple for this course.  But using it to make a digital thermostat (that is, adding control of a heater) would make it sufficiently challenging. The packaging in a plastic container as a case is a handy trick.

LATE submissions:

Here are my project ideas
Stop watch:
Other than hooking up the display, this is purely a software project.
Again, mainly a software project, other than hooking up the keypad and display.
And my favorite one… pulse monitor:
This is the third listing for a pulse monitor.

The word clock
Looks ok, but there would be a lot of soldering to do if we don’t have a PC board for it. Also, the crystal oscillators on Teensy or Arduino boards are not really great for high-accuracy clocks—good enough for short runs of a few hours, but not good for keeping time for weeks at a time.

OK, but mainly hooking up already designed modules with already designed software.  The soil moisture sensor is simple enough for students to design, but the software would almost all have to be just copied.
How to build an air guitar with arduino
Looks doable, though perhaps a bit tricky to get everything working with the level of skills in the class.
I think this project is perfectly doable, however, there could be small changes to make our easier. The ping sensor could be taken out and left as a four tone project. Instead of an accelerometer as the pick, a laser could be used as a string, similar to a laser harp. For this, the guitar would need to be mounted on one piece of material.

Very late submissions (more than 36 hours):

Speaker Volume Controller
OK, but a little bit special-purpose for the guy who made it.

Water level detector
Water tank level detectors are a fairly simple standard project.  It would be more interesting if the design contained a solenoid valve to turn the water on and off, rather than just sending a text message.

Smart Fan
This project seems to be about mounting a fan on a servo motor, so that it can be aimed.

Photogate Sensor
A photogate is a useful device in physics labs, but most of the design work is mechanical.

Ultrasonic Distance Sensor (on arduino)
Hooking up an existing ultrasonic module is pretty easy—I’d want to see either an application (using the measured distance to control something) or designing  the module from the bare transducers (see above).


Submissions more than a week late:

This highly ambitious projects calls upon students who value hard-work, are highly motivated, and who desire to take their education to the next level. This project presents a perfect synergy between its electronic and mechanical features. The integrated control board, the various sensors, and the opportunity for circuitry design combines with the water container, piston pump, and hot water tank to allow us to develop our technical electronic skills and apply them in an exciting, hands-on manner. The mechanical portions consist of simply connecting our water reservoir to our hot-water tank via piston pump. The electronic portions, on the other hand, present a wide variety of integration with the circuit board to multiple sensors measuring water level in both the water reservoir and hot water tank, as well as LEDs that tell us when the water level is too low. We will also strengthen our basic coding knowledge by creating the code necessary to smoothly transition and operate the separate phases of this machine at the push of the button. The actual mechanism by which this project works is surprising simple. This piston pump draws water from the reservoir and places it inside the already filled hot water tank. This pushes the hot water at the top of the tank into a tube and nozzle leading to the coffee contents in the K-cup, which filters straight into the cup. This entire process, of course, is handled by electronics involved. This project will not be a walk in the park by any stretch, but it will prove immensely rewarding to those brave enough to take it on. Beyond truly creating this Keurig machine,  we will more importantly be forced to greatly broaden our electrical and engineering knowledge and develop the confidence needed to continue taking on ambitious projects of this nature and scale.
This is an extremely late addition to the project list, from a student who apparently did not read the homework instructions to comment on other students’ suggestions, rather than proposing yet more projects. It also would be very difficult to do in the lab space we have available (no water, very limited mechanical construction tools).

Hey I saw another cool project on facebook. What do you think of building a camera system/computer program that tells you the shortest moves to solve a rubix cube?

 I think that the programming is way beyond the scope of this course.

2015 January 19

More on freshman design projects

Filed under: freshman design seminar — gasstationwithoutpumps @ 22:01
Tags: , ,

In Student project ideas for freshman design seminar, I listed some of the ideas students had brought up as possibilities for the freshman design seminar. For homework, I had them each comment on at least two other projects on the class e-mail list. Today, I counted commenters on the various proposed projects for the freshman design seminar:

5       temperature sensor (IR? I may have been lumping a couple of different temperature sensor ideas together—I did not follow all the links.)
4       PCR machine
4       blood pressure monitor
3       photogate
3       pH meter
2       colorimeter
2       EKG
2       fume extractor
2       sound level meter
2       centrifuge
1       microbial fuel cell
1       photospectrometer
1       general sensor
1       pulse monitor
1       function generator
1       lensless microscope
1       voltmeter
1       LED color mixer
1       motion sensor
1       stir station

I notice that no one picked the bacterial incubator project this year, which is too bad, as I have a dozen styrofoam shipping boxes that would be ideal for the project, and I spent a fair amount of time figuring out how to do the control loops (Temperature-control project for freshman design seminar, PWM for incubator, More on incubator design, Thermal models for power resistors, Thermal models for power resistor with heatsink, PWM heater and fan, PWM heater and fan continued, Controlling the heater and fan, Putting the heater in a box, Improving feedback for fan , Thermal control loop working (sort of)) and how to teach them.  Of course, given how much time it has been taking to teach reading a simple photodiode, I don’t know that I’d actually have been able to get through teaching proportional-integral control with anti-windup provisions, so maybe it’s just as well.

We’ll discuss possible projects on Wednesday.  I think that I can cross out a few as being unsuitable for the lab facilities we have available (no sinks, so wet-lab stuff is not reasonable) or as pointless, and one or two as too ambitious, but most of the projects are reasonable.  They vary a lot in difficulty, though, so I’ll have to help the students match their ambition with their willingness to work.

2015 January 10

Student project ideas for freshman design seminar

Filed under: freshman design seminar — gasstationwithoutpumps @ 10:27
Tags: ,

For the first assignment in the freshman design seminar for W 2015, I had students look on the web for ideas for projects they might want to do.  I had set up the theme as “thrift store science”: do-it-yourself lab equipment of quality suitable for middle school or high school labs (though not necessarily with the durability that school lab equipment usually needs).

Grading for this assignment is simple—it is basically a check whether or not the students have done the assignment, submitting at least one project with a URL. I set the deadline for the project as midnight on Friday night, and 16 of the 20 students submitted by the deadline.  I’ll add  late work if the students ever submit it, but those students may have less chance of their project ideas getting accepted by the class.

Their next assignment will be to read project ideas that sound interesting to them from at least two other students and amplify on them—more links, discussion of possible difficulties, discussion of possible solutions, other ways to achieve similar goals, … .  That discussion will happen on a private e-mail list for the class, as blog comments are too public to require students to participate.  If any of the readers of this blog want to comment (for the students’ benefit) on any of the projects here, feel free to!

I’ll only comment on the projects after the students have researched and discussed them some more, though I may make some general comments about the relative difficulty of mechanical, electronic, and programming design.  My experience is that programming allows more complex solutions, but simple programs are easier to build and debug than electronics for the same task, and both programming and electronics are easier to build and debug than mechanical designs.  Modern engineering tends to push design problems out of  the mechanical realm into electronics as soon as possible, and out of electronics into programming. Of course, any project will need some mechanical design, if only a box to put the stuff in.

Here is what they came up with, in their own words (with spelling corrected, but I’ve not added any comments—the comments are all from the students themselves):

Temperature sensor

Propeller-Powered Pendulum
LED Color Mixer

I had an idea to make a IR temperature gun. This seemed like it would be a fun project that wasn’t too hard.  This is how they work:
This is a fairly advanced version of it. I am not sure we can do something this technical but it contains a lot of helpful information:
I think it would be a ton of fun and maybe do able if we use the code provided in the link above. Otherwise we would have to find a way to program in assembly and that doesn’t seem feasible.

I think it’d be interesting to make a Phototrophic biofilm microbial fuel cell, it sounds complicated but it’s just a fancy way to make a fuel cell that uses the products of microbes metabolism to create electricity. The interesting part about this project is the use of photosynthetic organisms and metabolism to create electricity, it would combine many areas of science from chemistry, physics, to biology together which I think would cover almost everyone’s interests. These fuel cells are very efficient and are relatively simple to make from what I’ve read and the diagrams I’ve seen, let me know what you think.

Links for information about the science behind the cells:

Instructions on how to make one:
The Vernier UV-VIS Spectrophotometer is used to measure the the absorbance of chemical and/or biochemical substances.
This Pasco Spectrometer is made to expand and sharpen the details up close of the images students are observing.
This project involves constructing a “pulse sensor” that would monitor your pulse.  The project relays the infrared light reflected by the pulse into electronic signals.  This project would be be great if we decide to use the Arduino.
In this project, a temperature sensor will be made using an Arduino board.  This project will provide good practice for both programming and analyzing circuits.
DIY blood pressure monitor with a hand-cranked box as the power source. This website has many other DIY projects, including projects non-science related.
This sucks away fumes that can be present at chemistry experiments, which could cause hazardous situations. This website has many other projects.
A centrifuge that is simple and easy to use. Saves lots of money compared to centrifuges sold to schools. This website is a science magazine website that has many DIY projects.
An LED light casts a shadow on your object on the image chip, which creates a microscopic image that can be displayed on your laptop.
Can measure time very accurately in physics experiments. Can measure acceleration with 2 photogate timers. The DIY version is at a much lower cost.

“General Science” Sensor (Pasco): Multi-function unit for detecting scientific basics– relative light intensity, light per area/illuminance, temperature (basic thermistor), environmental noise, voltage. User manual.
Conductivity Probe (Pasco): Measure a solution’s conductivity. Does this count as wet-lab work? Household solutions could be used. User manual. Note: we may run into the “thin glass rod” problem described in class (as with the pH sensor).
Ethanol Sensor (Pasco): Detects ethanol in gas (or from the vapor a liquid emits). Seems like there’s a heating element whose applied current needs to be carefully monitored.
Doable with considerable effort:
This is my favorite so far -> Function/waveform generator (Pasco): synthesizes various waveforms (sine, square, triangle, sawtooth, etc) by cycling/stepping through frequencies at a designated rate. Should have wave type, frequency, step time/size controls as well as an audio output jack. A simple way to generate a sine wave, for instance, might be to cycle through a predetermined array of tones at even steps at a certain rate. Of course, a more advance signal generator would require high accuracy and a wide frequency range, so sticking to simple variable functions would probably be better. There are some guides online to compare; the main difficulty would come from finding parts and learning to solder.
EKG: Uses three adhesive electrodes to measure electrical heart signals (and thusly rate). / Hand Grip Heart Rate Sensor (Pasco): Determines heart rate using two metal handles. With all of these sensors I’ve posted, an interesting way to boost the difficulty would be to integrate an LCD to write out data in near-realtime.
Too ambitious:
Holter Monitor (Vernier): Continuous ECG, records and stores heart data over long periods of time (for later interpretation).
Induction Loop Generator + Receivers: Take an audio signal, convert it to electromagnetic waves, receive it on a second device, and convert it back into audio/electrical signal for headphones. (Holy big bucks, Batman!)
A cool non-lab-equipment project would be a dot-matrix clock using LEDs.
An ultrasonic “eye” would be cool/sonic locator. With enough practice, someone with visual impairment might be able to navigate a crowded space.

… a couple of website links for interesting projects for the BME 88A freshman design class. I was interested in using the concepts of sensors used in colorimeters or spectrometers in the biomedical field, so most of my links are based on biomedical engineering.
ECG and Pulse Oximeter
This device allows us one to detect and register pulse by emitting a shining light by an LED through the finger and detecting and amplifying the signal.
A soft robotic gel griping hand that works out of air. I believe this project could be better by using electronics to determine when the should the robotic hand should grip or not.
Biosensor that measure Elecromyography (EMG). This registers the electrical signals produced by flexing muscles.

The solid state heater is the norm with modern PCR systems (at least all the ones I’ve ever dealt with), but this leads to the problem of the thermal feedback loop and the heating/cooling systems being tricky to construct, as we talked in class. I have a modified version of this that I am attempting to design in AutoCAD, and I hope I can have a basic schematic in a weeks time, but my general idea is as follows:

A Cylindrical water bath container, split radially into 5 compartments which are physically isolated from each other to minimize thermal dissipation through the walls. The 5 compartments hold dH2O held at the 5 normal temperature steps (for Taq polymerase at least).

Denaturation Step: 94-98 Celsius

Annealing Step: 50-65 Celsius
Elongation Step: 75-80 Celsius
Final Elongation Step: 70-74 Celsius
Hold: 4-15 Celsius

In the center of the cylinder is a vial container (which extends out from the center over the water baths) which rotates to move the vials from step to step. It is spun by a small electric motor below the water bath assembly and the system moves as follows

elevate-rotate X degrees-lower

The advantage of this very preliminary idea is that it removes the necessity of changing the temperatures, instead only requiring temperature maintenance in the water baths, I do not believe the remainder of the project will be a significant issue, however testing the PCR machine would be difficult as PCR reagents can get pricey, (also a agarose and a gel box would be necessary and of course the loading dye and gel stain).

Idea 2:

This idea seems simpler, the hardest part seems to be the circuitry around the photodiode, which might be problematic but I don’t have enough experience with circuitry to fully gauge the difficulty in that part of design. I am spending time learning the fundamentals of various electronic circuit components outside of class so hopefully I will be able to send out a AutoCAD schematic alongside the PCR machine.

A idea I was kicking around was maybe an incubator in a spectrophotometer that gives live updates on cell population density in some culture in the cuvette, this is in case the spectrophotometer is too easy for a full design project.

I think a constructing a photogate timer would be a feasible project for class.

With this tutorial, the cost would be around $65 (not including the photo-interrupter), however this figure is based off purchasing materials from the “” website. The LCD screen for the readout and the FTDI basic breakout makeup most of the costs. Buying parts from Digikey would probably cut the costs down much more.

Our finished product would look more like the prototype in the beginning of the tutorial, since we don’t have the vernier photogates lying around (at least not to my knowledge). We could improve the design on the prototype photogate by creating a box enclosure for the hardware, like they did for their finished product.

I attached a powerpoint ( I found online of another quick tutorial on how to build a photogate. This one is pretty simple, one reason being they didn’t use an LCD screen. Like the previous tutorial, I think we can improve on the design.

I also attached a pdf ( of another project for the photogate. In this one, they constructed their own photo-interrupter, which is probably the best way to go as far as lowering the costs and adding flexibility to the design.

pH Meter

Instructions for a cheap pH meter. I know this may be a bit ambitious with our current electrical skills, but pretty cool nonetheless.

Sound Level Meter

No idea if this is doable, or too easy, but sounds pretty cool!
UVB Meters

It would be really cool to build something like this. I think it may be on the easier side though I’m not sure!

electric vacuum pump-

IR Thermometer-

Colorimeter to determine concentration of solution

UVA sensor to detect UVA radiation

Hey! so I’m not sure if this works and if it would be within the necessary work needed, but I was thinking of maybe designing a motion sensor. Here is the URL for a possible make it yourself sensor:

I found this website, Instructables, that teaches people how to make different types of gadgets or devices. I looked over the instructions and process of designing a voltmeter and it seems to be a pretty manageable project given guidance.

These two websites go more in depth about the different parts needed and seems to be a more advanced  and digital model of the voltmeter compared to the first one. There will be circuit boards and chips needed, which would give students more experience with electronics.

This website offers a cheap design,  using a total of less than 4 dollars  to build. He encompasses the use of a pedometer in his design, which I found very interesting.

Stir Station (Vernier):
This device is a combination of a magnetic stirrer and a ring stand and consists of a small platform attached to a stirring ring stand.  The platform is lit by LEDs to allow for better visualization of the liquid being stirred.  I think that this would be an achievable project.

Color Mixer (Vernier):
This device studies the mixing of RGB light by additive and subtractive mixing. The kit comes with intensity-controllable LEDs a lens, and a double sided screen.  I believe that this kit can be easily replicated, and we could possibly incorporate use of a colorimeter in later experiments.  For example, sending “mixed” light into a solution and measure attenuation of light.

A possible idea for a project is a basic temperature sensor similar to the one sold by pasco.
Vernier has a lab which vaguely explains one approach.
And here is a very low cost tutorial on how to create a temperature sensor.

describes how to build a photo gate timer using an Arduino board which I thought would be useful since the Arduino board was what we had decided on for our micro controller.

also another design for a spectrophotometer, looks fairly simple, also seems to work well with the couvettes we were given.

2014 May 2

Video of Designing Courses talk

Filed under: Circuits course,freshman design seminar — gasstationwithoutpumps @ 15:51
Tags: , ,

A week and a half ago, I gave a talk titled Designing Courses to Teach Design, after posting the text of the speech on this blog.  The talk went fairly well, though the time limit meant that I had to read the speech, which I’ve never done in 32 years of teaching.  It was kind of weird having a set speech to give, rather than extemporizing as I usually do.

The whole forum was videotaped and is available online (as a 784 Mbyte downloadable .mov file) from So you think your lecture course is better than a MOOC? April 23, 2014.

I was the second of six speakers and got some good questions.  Of the forum speakers, I think I liked Michael Chemers’s presentation best—he’s a theater teacher and has had more training in connecting with an audience than most faculty, but the content was good also.  (I don’t think the Prezi added much to his presentation, though.)

Next Page »

%d bloggers like this: