Skip to content

20. Project Development

We are closing in to the final weeks of Fab Academy. This is the last week before final project presenations. I need to evaluate my project plan and apply some time management to make sure I finish everything.

Completed Tasks

When making this list I feel like I might be tricking myself because I feel like I have most of the core elements of my final project done.

Power Tower

During Week 8 - Computer Controlled Cutting I designed a wooden tower to power the robots of my final project with metal cables. The towers were cut on the shop bot and take one sheet of plywood.

Bearing Power Bus

The cables on the power tower are connected to the positive and negative terminals of a 5 volt power supply. I wasn’t sure how much resistance the cables would have and if the bearings would seamlessly connect to the cables to transfer power. I tested one prototype robot on some cables and it worked great. The resistance on 8 feet of cables is just a few ohms and can power multiple robots at one time.

Wireless Communication with ESP8266

In Week 14 - Networking and Communication I was able to get wireless communication working with two ESP8266. It was actually pretty easy to connect to a wifi network and send a variable back and forth.

Custom NEOpixel Propeller

I prototyped first with a purchased light strand. The pixels were an inch seperated and didn’t create the effect I was going for. I was able to mill a simple board with traces for the +, -, and signel pin. I 3d printed a mounting plate to connect the propeller to the slip ring. The LEDs on the custom propeller are right next to each other and make a nice circle of light.

Remaining Tasks

Parse website for Data

Until I get the custom build water sensor finished I think it will be quicker to parse the water level from an exhisting website that monitors the lake. I think I can get the value from this website . I have used processing to parse HTML pages and it can communicate with hardware via serial, like I did in week 16 .

Build ESP8266 board with LED and Motor Control

In the week 16 I built a ESP8266 board that can power an LED and now I need to add another output to that board to control a motor. The board outline also needs to be adjusted avoid the bearing and slip ring.

Make Multiple bots

I took this project to SOLIDWORKS World 2019 like I mentioned last week. At the conference I worked in Fab Lab Houston’s Mobile Fab Lab to make 8 robots. We tested them with store bought ESP8266 arduino boards. Once I make one in the Fab Lab I will need to add them to the hardware we put together at the conference.

Things that worked well

Slip Ring

These slip rings are amazing! I am interested in trying to make my own but it would be hard to recreate the small package of these. There is no loss of signal as the LED spins.

Threading the Acrylic

I made some parts out of 3D printed PLA and some parts out of laser cut acrylic. I struggled to figure out how to combine multiple materials because more adhesives are made for specific materials. I found some Taps and laser cut some holes the same size as the drill bits that came with the taps. The acrylic threaded very nice and the screws are very sturdy when tightened down.

Things that aren’t working

Bearing for Moving Power Bus

When I started I wanted to have the robots move up and down the cables and use the bearings to transfer power. I thought maybe the cable would touch the bearing and the energy would transfer through the bearing. Then, I could connect a wire from the screw at the center of bearing to the ATtiny. Turns out the grease inside the bearing doesn’t conduct electricity.

Robots slipping

The robot worked great on the cables due to the tension of the cables. When I put more than one robot on the cables it helped space them and reduce the tension. This caused the robots to slip down the cables.

I need to redesign the bearing holders to prevent the bearings from moving and connect the ATtiny to the cables.

Questions that need answers

Stream Data

How can I get updated info to the robot and will people be able to understand the connect between the data and the color/patterns?

Slip Ring Lifespan

The slip ring is a fun solution but I’m not sure how long it will last spinning all the time. It is nice because when the robot is off the propeller stops and what was a circle of light just becomes a thin line.


Below is the schedule I am working from, based on what Neil posted. ------Finish remaining assignments & prepare for final presentation (now)

June 14: Be prepared to present final project ------Finish remaining assignment

Jun 19: have every week submitted for evaluation ------Start making edits

Jun 26: receive all feedback ------Know all edits to be made ------Finish making edits by July 3

July 3: last date to submit review feedback

July 10: last date for decisions in this cycle post-evals did present, didn’t finish: rolling reviews up to December 1 didn’t present: present at start of January cycle

Lessons learned

I have learned tons of technical skills throughout this. I’ve used Arduino for years and never really understood TX/RX pins. Arduino does a good job of putting black boxes around things. This makes things easier to get working but harder to learn deep.

Several times I’ve purchased blank Atmel chips and have been unable to program them. Fab Academy helped get me over the hump by presenting resources for setting the fuses of the chips.

Beyond the technical skills one of the toughest things I learned was to do a better job documenting on a backed up system and don’t procrastinate. Neil has said not to document last every week and for students to document and push online as progress is made. I thought if I at least documented everything as I went I would be in good shape. Unfortunately, all my documentation was on my cellphone and my cellphone crashed. I took it to the Apple store but they could not recover anything from the phone. Now I am weeks behind and need to re-document a bunch of things for the weeks projects.