Here is an overview of all the most interesting tech projects I've worked on recently, although some have been omitted due to a lack of pictures or an unsatisfactory conclusion.

Water Purification

I was talking with a friend about the water crisis, specifically in Cape Town, and she argued that many of humanity's biggest problems will not be solved unless millions of people can work together and put their individual interests second. Given how unlikely this is to happen, I would argue that only money and science can provide the alternative solutions that we need. This project (which falls under the second category) is my contribution to the solution.

The goal of this project was to distil potable, clean water from seawater, with a low energy cost. Generally, distillation is extremely inefficient because so much of the heat is lost to the environment. However, if the boiling point of water can be reduced to a temperature that can easily be generated by sunshine, then inefficiency would be inconsequential. By generating a vacuum in the still, then the difference between the vapor pressure of the water and the atmospheric pressure will be much lower, and less energy will be required to boil the water. Here is a mockup I did in Fusion 360: Rendering of water distillation device The seawater is stored in one side, the valves are closed, and a pump attached to the vacuum hose is used to decrease the pressure in the apparatus to the about 21 mmHg, or the vapor pressure of water. When this pressure is reached, the water will boil until the pressures equalize again. If one side is heated and the other is not (accomplished by painting one side black and the other silver), then the water in the hot side will boil, reach the refrigeration coil, and condense into the other side.

$100 and a trip to the hardware store later, I have all the components I need. Parts The final parts list was:

  1. 2ft of 2in pvc piping
  2. 6in of 1/2in pvc piping
  3. 2in pvc end cap
  4. 3 2in pvc couplings
  5. 2ft of 2in pvc piping
  6. 3 2in to 1in pvc reducing adapters
  7. 3 1in to 1/2 in reducing adapters
  8. 2 1/2in pvc to 1/2 in steel male threaded adapters
  9. 2 steel 1/2 in Ts
  10. 2 1/2 in to 3/8 in compression fittings
  11. 1 1/2in to 3/8in steel reducing adapter
  12. 1 1/2 in ball and socket valve
  13. 1 1/2in steel pipe nipple
  14. 1 pressure gauge with a 3/8 in male stem
  15. 2ft of 2in pvc piping
  16. 10ft of 3/8in refrigeration coil
  17. 10 ft of 3/8in vacuum line
  18. 1 1/2in to 3/8in barb fitting
  19. 1 1/2in pvc ball and socket valve

I started by assembling the pvc components, allowing them time to dry while I screwed together the metal components, using Teflon tape to seal each of the joints. the PVC assembly the gauge assembly the valve assembly All in all, the project only took one day to complete (excluding testing). the complete purifier Of course, this prototype is not suitable for continued use - the pcv would deteriorate in the sun and the volume is too small - but it will work well for testing. The saltwater side (with the ball and socket valve) will be painted black so it heats up in the sun, and the volume of water in the other side will be used to determine the efficiency over time.

The next step was to create a vaccum pump that could be replicated easily and at low cost. A brief internet search yielded many many results, and I decided to construct a pump using a cheap bike pump. Online, many people had described rotating the valves around to change the flow of air, but the pump that I purchased was too cheap and had the valves built into the plastic.

To reverse the pump, I started by flipping over the seal on the inside of the plunger so that it would allow air to flow in only on the downstroke. the top of the bike pump plunger I could now crush water bottles, but without the one way valve at the bottom, I couldn't get more than one stroke. To fix this, I used NighHawkInLight's design for one way valves with some pieces of an inner tube for a bike, and it worked splendidly! a small one way valve Now I'm only waiting for a new negative pressure gauge: after that arrives, I can begin testing.

The High Altitude Balloon

This project was for an Aerospace class at East High School, which aimed to obtain pictures of the curvature of the Earth and collect data on various atmospheric pollutants on the way.

The balloon project will only be discussed here in its capacity as the most complicated PCB design and fabrication I have ever done. Other information can be found on the HAALO website or through East High School.

All of the electronics for the balloon were custom built and designed specifically for this project. We started by identifying all of the functions that we wanted to be able to perform...

  1. Communicate with the ground station
  2. Read its position using GPS
  3. Measure temperature, pressure, and humidity
  4. Measure ozone, carbon monoxide, and particulate matter levels
  5. Take and transmit pictures taken during flight
  6. Cut down the balloon if necessary, as required by the FAA
  7. Save all flight data to a microSD card
  8. Facilitate easy retrieval (using a beeper or light)

...and then creating a diagram to show the flow of information between each system: diagram of the balloon controller We decided that it would be easier to manage and test the computer if we created a printed circuit board for it, especially given my experience with the breadboard STM. I had only very limited experience with etching PCBs using ferric chloride, and even less with Fritzing, but we were not to be deterred!

Given tight budget constraints (other groups of students were working on obtaining funding, and deserve great praise for their hard work and genius), we created the parts list before we finished the schematics. For those who are interested, it can be found here.

After only a few weeks of planning, the outreach team secured over $2,000 for the completion of the project! All parts were ordered, and we began work on the schematics. After struggling to find parts that were already present in the Fritzing libraries, we switched to Altium Circuitmaker (another free PCB design software) because it had better support for custom components. Here is the schematic, version 10: balloon schematic By using JST connectors for all of the sensors, the computer could be kept warm within the housing while the sensors were exposed to the environment (so they can take data). Unfortunately, the complexity of the board combined with size constraints meant that the PCB would have to be double sided - a unique challenge in alignment.

The general process for creating a PCB is as follows:

  1. Create a design for a PCB on Circuitmaker, Fritzing, et cetera
  2. Spray paint a sheet of copper clad laminate
  3. Use a laser engraver to etch the negative of the PCB design, with careful scaling
  4. Expose the PCB to ferric chloride, which will oxidize the copper
  5. Use a micro drill bit to drill holes in each of the pads
  6. Fit each of the through holes and vias with rivets
The PCB design from Circuitmaker

This is a screenshot of the design from Altium Circuitmaker. I excluded the polygon pour (which means less acid is necessary to etch the PCB) so that the bottom layer (shown in blue) is more visible. I used a plastic based spray paint that I found at work to cover the PCB, and clamped it so that it could dry. the PCB covered in spraypaint I've found that certain spraypaints work better than others when being etched on a laser, and I've found that running the job twice helps to clear up a lot of the residue that would slow down the etching process. the PCB being etched This is the PCB while it was being etched in a 60 watt Epilog Fusion. By cutting a rectangle with the dimensions of the PCB blank, pretty precise alignment is possible. When one side was finished, the PCB was flipped over to etch the opposite side.

After the PCB had been etched, it was possible to see through the laminate in the areas where copper had been removed from both sides (such as around vias and headers). Unfortunately, it was pretty clear that the two sides were not perfectly aligned, and further inspection indicated that the PCB blanks were not really rectangular.

This was only the beginning of our problems - but we did find a solution. By painting only one side of the board, holes drilled in 3 vias could be used to align a vinyl cut negative on the other side. I spray painted over this and peeled off the vinyl before it was dry, then etched the PCB with ferric chloride as usual. The vinyl before weeding vinyl applied to the pcb peeling the vinyl off the painted PCB After etching and assembling this PCB, we realized that our sensors were all digital devices, not analog ones. We are still in the process of creating a new revision.


Scatter cloud logo Scattercloud is, at its simplest, a blockchain. The scatter.cloud blockchain (hereafter SCA) is designed to facilitate fast and byzantine fault tolerant transactions between clients on the network, using a derived consensus model for mitigating forks in the blockchain. Information on the development of SCA will be posted here, as well as code and instructions for accessing and developing on the blockchain.


I love microscopes! I was (and still am) inspired by the things they reveal, and with such simplicity! I've had a number of opportunities to design modifications to a cheap brightfield microscope, and I've compiled them here. These modifications have bene tested on Zenith school microscopes and an AmScope brightfield microscope I have access to at home.

I have also included a discussion of a variant of Dan Berard's STM I built a while ago, and a few other microscope hacks I've found and tested. Most of the images are of tissue paper at 100 to 400 times magnification. a camera mount on a microscope the camera mount with a phone attached These pictures show a phone camera mount for a microscope that I designed in FreeCAD. The mount is inspired by ggoss' Universal Camera Phone/Microscope Adapter on Thingiverse, and was used to take all of the pictures in this section. For those who are interested, the STEP file can be downloaded here.

The first modification changes a traditional brightfield microscope into a darkfield microscope, which provides better contrast by showing an illuminated sample on a dark background.

Brightfield microscopes block the light coming directly up through the condenser, so that the only light that passes the sample would miss the objective lens. However, some of the light that hits the sample is diffracted, and passes into the lens. Only the sample causes the light to be redirected, so the sample glows on an otherwise dark field, hence the name. This design is an improvement on the "One-Penny Darkfield Illumination Filter", described here. a 3D printed darkfield occulting disk The disk is designed to fit inside the diaphragm of a Zenith microscope, so that a user can switch between darkfield and brightfield by rotating the diaphragm. Here are the results: brightfield view of paper fibers darkfield view of the same fibers These images are good for illustrating the differences between the two microscopes, but they are poorly focused (my piece of tissue paper was not very flat). Better clarity can be achieved using a slide and a smaller sample: more fibers under a darkfield microscope a slide of yogurt viewed under a darkfield microscope The details become much easier to see under a darkfield microscope (and they look cooler too!). The file for the occulting disk is here.

The next hack is much more interesting, but the lack of an appropriate sample makes the images slightly less picturesque. By illuminating a flourescent sample with UV light, it can be caused to glow. By using a highpass filter to block the UV light, only the light from the sample is visible, so certain proteins or indicators (like GFP) can be used.

For each of these samples, I used tissue paper that had been marked with highlighter, because it was flourescent (and I could not afford or effectively use flourescent samples). an image of tissue paper fibers in a brightfield microscope This image shows the contrast between the flourescent (highlighted) and normal fibers in a brightfield microscope. The image is poorly focused because the sample was too large, and the highlighter prevented me from using water or a coverslip.

The first iteration of this design was created using a stack of purple plastic rectangles cut from a divider in one of my binders, and a set of safety glasses with yellow lenses. The purple sheets were placed on top of the light beneath the stage, and acted as a filter. the same image, under a flourescent microscope It worked! Sort of. Although the highlighted side is much more clearly distinguishable, ideally, the non-flourescent areas should be invisible. Additionally, using a filter to create high frequency light assumes that the microscope's bulb already produces light of that wavelength. I removed the lens on the bulb on the AmScope microscope, and its tungsten filament bulb worked. The Zenith school microscopes did not work so well.

With this in mind, I purchased an LED from Mouser ELectronics with a wavelength of 475 nm, selected to be the highest wavelength that could (theoretically) excite GFP. I also purchased a 510nm longpass filter from Knight Optical. The acrylic filter itself was only six Euro, but with shipping, handling and tax, I ended up being charges almost $30. With that in mind, the filter was removed from consideration as a possible component in the final solution, but it would still be useful for comparison. the led attached to a battery the led illuminated behind the longpass filter The filter significantly decreases the brightness of the LED, and the datasheet indicates that very nearly 100% of light under 500nm is blocked out, so the remaining light should all be a result of a wider wavelength range coming from the LED. epiflourescence with an led The led did create more contrast (using a different sample, obviously), but light pollution (if you will) from the LED that was not blocked by the filter made the sample hard to look at. Using a darkfield occulting disk in conjunction with the LED did a lot to solve this problem. epiflourescence with a darkfield occulting converter This modification works even without the lense, depending on the sample. More work will be done to create cheaper and more effective longpass filters, ideally with adjustable thresholds for use with different indicators. It is important to note that this microscope only works in the dark, or with a towel or jacket wrapped around the stage and objective lenses.

I have not limited myself to optical microscopes. After trying (and failing) to find instructions online for building a scanning electron microscope, I stumbled upon Dan Berard's STM. Dan Berard had taken a concept originally described by John Alexander and developed a functional and refined STM using a piezo element. I would highly recommend Dan Berard's website for nayone who is interested in this project, his descriptions are incredibly clear and he has made available everything you need to create your own. So that is exactly what I did. piezo elements on a table At the heart of the STM is a piezo amplifier. They are used to build impact sensors and guitar amplifiers and they are extremely cheap: I purchased this bag of 20 on ebay for only $3. The thin white layer on the piezo disk is piezoelectric ceramic, which flexes when electricity is passed through it. John Alexander showed that by cutting the ceramic into four quarters, the disk could be made to flex in a specific way. the piezo disk cut into quarters An atomically-sharp tip is made by shattering tungsten wire with a set of wire cutters, and then mounted on the center of the piezo disk. An oscilloscope sends a sine wave to the piezo scanner, which moves back and forth, and the current flowing from the tip to the sample surface is amplified and measured, which creates an image. I used John Alexander's amplifier circuit because it is simpler, albeit less refined, and remade the circuit on Fritzing to prepare it for breadboarding (yep, I did that). My adaptation of Alexanders' XY controller My adaptation of Alexander's amplifier These are my adaptations of John Alexanders XY Controller (top) and amplifier (bottom) circuits, done in Fritzing. These schematics are ideantical to those published on Alexander's Website, but re-creating them in Fritzing allowed me to manipulate them and alter the layout. I ordered the parts from Mouser Electronics, and started designing the mechanics of the STM.

This is what I put together in FreeCAD: a mockup of the STM in FreeCAD Everything about this design is inspired by Dan Berard's STM, with acrylic plates for vibration isolation and three BYJ-48 stepper motors instead of one for full range of motion. The STEP file for this design is available here.

I learned then that cutting acrylic without a laser cutter (a convienience I had yet to have access to) is hard. The top and bottom plates were not straight, but the edges did not matter as long as the holes were all aligned. I had more difficulty mounting the stepper motors to the acrylic, because the screws would fracture the plastic as I inserted them. Here is the final STM: the assembled structure of the STM To further isolate vibrations, I used sections cut from three drywall anchors to couple the stepper motors to the actuators. Now it was time for electronics: a messy breadboard with the STM electronics A relatively simple circuit became incredibly hard to manage when built on a breadboard. After hours of finding problems and adjusting component positions, I finally recieved a signal. I combined the electronics with the mechanical components, and I was ready to run my first test. the completely assembled STM The Arduino Mega acted as the oscilloscope required to send a signal to the probe, while an Arduino Uno measured the signal from the amplifier circuit. A script written in Processing showed the oscilloscope readings on my computer screen. The BYJ-48 Happy Drivers are disconnected after homing to prevent wobble, an idea suggested by Dan Berard.

These readings are the closest that my STM got to being operational: a screenshot from processing showing STM startup a screenshot showing the tip crashing into the sample The first image shows the readings when power is first sent to the STM, after which it begins scanning. The second shows the reading I received after accidentally crashing the tip into the sample (a piece of flattened copper wire). It is quite likely that these readings are entirely insignificant, or merely due to static.

I have since scrapped the STM for its components, but I really would like to try the project again, armed with a better understanding of electronics and the ability to make PCBs, which would help with debugging and analysis.


Kites are really simple and really fun. Very little beats being outside on a windy day with a kite... except maybe FPV kites.

After being frustrated by the short duration of FPV drone flights, flying a kite seems almost too good to be true, especially when you have two people. The only difficulty is in positioning the camera so that it does not flap in the wind. The first step is building a kite. The parts laid out for a kite The parts for the kite include a few sticks (I had three carbon fiber tubes laying around, but they certainly aren't necessary), a trash bag, some tape, string, and three sheets of paper. Tape the sticks together to form a diamond, and cut open the trash bag. The cross set on a garbage bag Cut the trash bag to fit around the cross, and attach a length of string to the cross spar. The string attached to the kite A piece of tape on the inside of the string keeps it from falling inward. To create a streamer, remove the drawstring from the bag (you might have to cut it in half), and tape it to the bottom of the kite. Cut a sheet of paper in half, and crumple the middle until it forms a bow. Repeat these steps until you have six bows, then tape these to the streamer. The kite is ready to fly! the diy streamer the finished kite The FPV setup is also incredibly simple. I 3D printed a set of VR goggles from Kuutio3D on Thingiverse, and set up a 5.8 MHz reciever for a cheap FPV camera. I crimped header pins onto a battery and onto the leads on the camera, so they can be clipped together easily. the components for the FPV setup The camera was the cheapest I could find on the internet, so the images aren't great, but they are still pretty entertaining: an image taken from the kite an image taken from the kite Of course, it is nice to have control over your direction, and for that, we have drones. Due to the popularity of drone piloting, building and flying all kinds of drones is pretty straightforeward. My best-documented drone project was for an engineering class in 2017. a small 3D printed drone This drone was built from parts scavenged from other drones, fit into a body that was stress tested and designed for weight. The body was designed in an educational version of Autodesk Inventor Professional CAD software. a screenshot of a static stress analysis After 3D printing, each of the parts snapped in, the battery was glued on top, and the drone flew! The drone body on a 3d printer The drone with propellers spinning Recently, I became more interested in building rc planes instead of quadcopters because of greater efficiency and load capacity. I don't have pictures of all the builds, but here are each of the finished planes (not all of which flew). my first foamboard plane It's pretty obvious why this plane didn't fly. The enormous battery on the nose threw it into a dive within a few seconds of launch every time. The Flite Test Tiny Trainer After my failure with the first flying wing, I decided to go back to the basics. My friend and I built the Flite Test Tiny Trainer. This plane glided beautifully, but we did not have a programmable electronic speed controller, so we did not put a motor on it. We still have the plane, and the only thing preventing us from flying it is time. A choroplast glider I designed This was the ultimate glider project. Designed after the Horton H IV, this glider was built out of choroplast for stiffness and waterproofing, and could support a pushed propeller as well. The plan is to tow this plane behind a kite, then release it with a servo and fly it to the ground using a remote control. A view of the airfoil of the glider The glider is built with a steep airfoil and dihedral wings for stability at low speeds, and uses only three channels. Like the flying wing, the elevator and aileron functions are combined using a V-Tail mixer.

Finally, setting all elegance aside, there are blimps. This project is more silly than useful or cool, but in retrospect it was one of the most fun things I've built all year. the happy cloud blimp This project was done with my sister on a weekend with nothing else to do. We removed the electronics from a cheap 2 channel RC car, and replaced the electromagnet used for steering with a small dc motor from a drone. We fixed propellers onto each of the motors' shafts, and attached them, at right angles, to the bottom of a helium balloon we bought at a grocery store. By adding coins, we could make the balloon slightly less than neutrally bouyant, and by angling the propeller downward, we could control both the height and the foreward velocity of the balloon simultaneously. The othe rmotor was used for steering. another view of the blimp The blimp flew remarkably well. The incredibly slow speed and low risks involved with collisions meant that it was not as difficult to fly as one might expect (untill all of the helium leaked out of the mylar).

Rocket Engines

This was probably the most entertaining project I have worked on recently. A series of discussions with my chemistry teacher about the role of iron oxide in dry rocket fuels demanded experimentation, and after researching rocket candy online, I realized that it would be very possible to create solid fuel rocket engines without any expensive materials or special equipment. sugar, corn syrup, postassium nitrate, and Black Iron Oxide These are the only things you need to make rocket candy, in fact, you could probably get away with just the potassium nitrate and sugar. The postassium nitrate is a strong oxidizing agent: when it is added to the sugar (which would burn slowly anyway) it speeds up the reaction to the point where the exhaust gasses produce meaningful thrust.

In my recipe, corn syrup is used as a binder until the melted sugar is added, which results in a pretty gooey mixture until it dries. It is also very popular to add Iron Oxide, presumably as a catalyst, to increase thrust and burn rate. paper mache tubes for the rocket motors I started by making a bunch of paper mache tubes for the motors, each with a capacity of 5ml. This proved to be a mistake, because the tiny surface area of the fuel column caused an extremely slow burn rate. the rocket fuel before adding Iron Oxide the rocket fuel after adding Iron Oxide As it turns out, black iron oxide is the key ingredient in a lot of toners, which explains the inky black color. After adding the melted sugar (outside, wearing PPE and with a fire extinguisher handy), it was time to fill the tubes with rocket fuel. filling the rocket with fuel This was not as easy as I thought it would be. As the sugar cooled, the fuel became hard and chunky, so it was difficult to pack into the tiny tubes. Additionally, the fuel was extremely sticky and it would stain anything it came into contact with. a set of finished rocket engines When all the fuel was packed into tubes, I wrapped them in one more sheet of blank paper, and they were ready for testing. the less than spectacular burn of one of the rocket engines It is illegal to launch a rocket with a custom motor (like the ones I built) in the United States without a liscence, which I am inelligible for because I am not yet 18. It is not illegal, however, to burn these motors on the ground, so I built a small mount using a few bricks and tested them in my backyard. a closer view of the rocket engine As you can see, the motors did not produce spectacular plumes of exhaust. This is a consequence of two things: first, the rediculously small amount of fuel in a long tube yielded a long burn time with very little thrust. Additionally, the paper mache tubes were not completely dry, so they did not burn away as they should have.

I will be rebuilding these engines with different amounts of FeO and Fe2O3, with a larger surface area and thinner tubes.

Biofuel (Pyrolysis)

Returning to the "money or science" solutions to global warming, what better way to prevent greenhouse gasses than by synthesizing oil? During WWII, the British used "syngas" to fuel cars and tractors, and it amazed me to learn that we have been capable of producing oil from complex hydrocarbons for decades, and yet no one was working on producing refined gasses (like petroleum) from waste biomass.

In an attempt to better understand the hurdles we were facing, I decided to build a pyrolysis reactor. The principle of operation is that heat and pressure cause longer hydrocarbons to break down. Lower London dispersion forces in these molecules means a lower boiling point, and when they reach the appropriate size, they flow up through a condenser and drip into a container. the pyrolysis reactor on a grill My reactor was built from a bucket with a refrigeration coil flare-fitted to the lid. This provided an airtight reaction chamber that could be easily opened and inspected, although soldering the flare fitting to the lid of the paint can was not easy. I ran the refrigeration coil through a bucket of water to enhance cooling, but removed it later because condensed gas in the coil in the bucket caused a rise in pressure in the container. a test tube filling with biofuel I managed to extract about 60ml of gas from a few apple cores, dried leaves and sticks, and 30ml from scrap PLA from 3D prints. I did not control for input volume so these numbers do not reflect efficiencies. another tube of biofuel I did note a huge difference in color between the PLA and organic matter - the PLA produced a much clearer oil. This is most likely attributable to the consistency of the material in the PLA trial, and the PLA had already been processed. I will work on distilling and refining these samples with my chemistry teacher.


I have so many more projects that I neglected to document, or that just weren't worthy of mention on their own. I've included pictures and brief descriptions here. a delta 3d printer This is a delta 3D printer I designed for my friend, who I was working with to build a printer capable of printingin aluminum using a MIG welder. We never bought the welder (turns out they are pretty expensive), so we never used it. a 3D printed breadboard I need a breadboard... why not 3D print one? ...because you need clips. Tin foil works extremely well until it falls apart. a cardboard Go set a diy wooden Go set a diy version of the game "Monopoly" a diy chessboard and set Board games are fun, especially Go and Chess. Unfortunately, it's hard to keep a set handy at all times (and nice go sets can cost $30), so I've found myself making my own more often than I'd like to admit. I use the black Go set all the time; all the lines were made in a scrap of chalkboard with a eye bolt and a ruler, and the pieces are knots of rope tied by rope with the ends sealed with a candle. a cnc machine made from MDF running with a 2 foot by 4 foot sheet of 3/4in MDF This project was so much fun! My friend and I decided we were bored with 3D printing and wanted something slightly more dangerous, so we went to Home Depot and bought 2' by 4' sheet of 3/5" MDF, and built a CNC machine. At the time, however, neither of us were old enough to drive, so we had to tie the MDF to my bike, and run it back to his house. The CNC machine worked, but we were both hired by Mindcraft Makerspace within the month and the laser cutters there made our CNC machine pale in comparison. A diy filament extruder for waste PLA Over the last few years I've accumulated several kilograms of PLA scraps from failed 3D prints, and I needed a way to recycle them. PLA filament costs $25 per kilogram, so when I heard that it could be recycled, I built a small single-screw extruder. The rig worked, but to get high quality filament, the pieces of plastic fed into the extruder had to be really small. The next leg of this project will be to design a plastic grinder. a diy soldering third arm The first time I used a third arm for soldering, I knew I had to have one. In true maker spirit, I decided that buying aligator clips on Amazon would be cheaper than buying a third arm. I crimped the clips to two 12 gauge wires wrapped around each other, and covered each of the teeth with heat shrink, and voila! Functional 3rd arm! I bolted three arms to my work surface (an old cutting board), and I was ready to go. a breadboard design of a spectrophotometer a breadboard design of a spectrophotometer a breadboard design of a spectrophotometer This project was, in every regard, my biggest failure (and that is saying a lot). My biology teacher had asked me to build a spectrophotometer for the school, which seemed simple enough. For those who are unfamiliar, a spectrophotometer analyses the concentration of a sample by measuring the transmittance of the sample as different wavelengths of light are shined through it. Seems simple enough...

I mounted a fragment of a CD onto a servo motor, wired an incandescent bulb (for full wavelength) to an arduino set up with a photocell, and measured the absorbance as the servo moved a spectrum across the photocell. Nothing. This first attempt is the topmost picture above. When that didn't work, I decided to pursue a finite number of datapoints by using LEDs. I designed a new circuit to light one LED at a time and measure that absorbance, and I built it on protoboard (having been freshly traumatized by the STM breadboard) and it worked! All I had left to do was replace my Arduino Uno with the smaller Adafruit Pro Trinket!

I did not know that the Pro Trinket does not have serial communication. After a week or so of trying to solve the why-can't-I-access-the-readings problem, I destroyed the bootloaded and never succeeded in reloading it (I needed the very FTDI cable that could have saved me all that trouble in the first place). By that time I had run out of energy and transferred to East High School, so I gave up. If I have time, I would really like to take on this project again, with better judgement and more experience.