Hardware
Firmware
Software

This is a WindSonde, a device carried aloft by a weather balloon that reports altitude and GPS location back to a base station. My client uses these prior to launching their rockets to check wind direction and speed at various altitudes. The design started on a breadboard to test the interfacing of the various off the shelf modules, let me develop firmware, and gain overall confidence. This design combined an Arduino Micro, Adafruit GPS module, XBee transceiver, SparkFun barometric sensor, Pololu motor driver, and a bit of custom circuits.

I hand wired two perfboard designs, one for the client to test and one for myself. Perfboards are great if you need something fast, or something simple, and at the time it served the project needs. With the low cost and fast turnaround of prototype PCBs, perfboard projects like this are rare.

Once the client and I had completed testing of the perfboards, I moved the design a circuit board. The board on the left has all the modules soldered directly down (wouldn't want parts coming loose during the flight!). The board on the right was for testing and has sockets. I built up about a dozen of these for the client. Ideally, the WindSondes are recovered, but not all the time.

This design was for a differential drive robot that also had a tool (a weed whacker). An ST Micro Arm Cortex development board was interfaced to custom motor driver modules I designed based on a Texas Instruments low voltage, high current brush motor driver. You may also spot a Spektrum R/C remote receiver and an ST Micro accelerometer/gyro development board. The firmware for this project, which I also wrote, was started on mbed and then moved to a local gcc-arm toolchain.

A CNC milled daughter card integrating all the connections for the ST Micro development board (ok, it's actually two boards because the mill I used had a maximum milling area of 3" x 2"). You can still find the Spektrum R/C receiver, along with three custom motor driver modules, and an ESP8266 WiFi module. The popular yellow gearbox has a custom encoder on the back of the motor (CNC milled circuit, 3D printed housing).

And here's the final result... all assembled on a custom designed 3D printed robot chassis and a vacuum formed outer shell (googly eyes required!). Follow this link for a video of the robot: Robot Video.

Need an Arduino compatible processor board cheap enough you can give them away, yet complete with mosfets to drive motors, LEDs, buzzers, and it has an on board battery to boot? Then the EB1 is what you want. I co-designed this with Tully Gehan of Samurai Circuits to fill a very specific niche. Tully has much more information and his world famous paper robots at Robot Maker Club. I have some video demos of the EB1 along with my really inexpensive foam core robot being controlled by an EB1 here. The EB1 is in full production, in China.

Yet another robot controller. This one is a full custom 4-layer circuit board with an Atmel Arm Cortex-M0+ processor. It includes USB battery charging, solar charging, battery fuel guage, multiple high current load switches, four brush motor drivers, and a slew of I/O connectors for expansion (mainly serial or I2C). As with most of my low volume projects, I had steel solder stencils made, hand placed the components, and reflowed the boards all in my lab. This design certainly tested the limits of my lab assembly line with 0402 passives and a large number of very tiny QFN packages. Besides designing the hardware, I also modified the necessary code so that this board came up under the Arduino IDE. The processor is the larger pin-count version of the one used on the Arduino Zero.

Enough hardware already! My client had a robot that looked for a reflective tape along the ground to help figure out where it was. Unfortunately, the detectors they were using didn't have a very wide field of view, and the robot had to travel slower than they wanted in order to find and track the tape. I was brought in to try out some tape finding techniques using vision instead of simple sensors. The Homer Bot shown has an iPhone with a custom app (Objective-C) detecting a tape with a pattern. I also created another series of tests using a webcam with vision software running under Javascript in a browser (yikes! but it worked!).

This client's main business was after school STEM classes and summer camps. They started hacking up an R/C car to add an Arduino as a platform to teach programming. Unfortunately, they ran into some hardware issues and called me in to help. The original plan was to use these to teach soldering, electronics, and software (which I hope explains all the through hole components).

Along the way we determined we couldn't use the car bodies that came with the R/C car kit (umm, licensing?), so I designed a custom body that we could vacuum form. Here the body prototype is 3D printed in blue ABS. I had to print it in two halves due to the size of my printer. Even though the print wasn't perfect, it sure was a helpful reality check.

In the end, I designed the circuits, came up with the car chassis modifications, designed the laser cut plate to hold the interior electronics, designed the vacuum formed body, created video assembly instructions, and worked with multiple Chinese suppliers to get it all done and delivered (phew!). Oh yeah, and I took this through FCC compliance testing, which it passed after slight modifications to the transmitter's circuits.