Sometime in 2017 I gained an interest in basic Printed Circuit Board design. I had been using a Raspberry Pi to control my homebrewery for some time with various software, and was growing tired of trying to arrange components and solder wires on prototyping boards every time I wanted to make a system change. Messy and not that fun. PCB design on the other hand could be perfected on a computer, and ordered/printed for cheap. They are also easy to share with others.
Many prototyping boards like this had been soldered up over the years
The first board I made would do a couple things:
- It would use a transistor array (ULN2803) to increase the effective voltage and current I could output from a Raspberry Pi. The purpose of this is to reduce current draw on Raspberry Pi GPIO, and increase reliability when using Solid State Relays and Relay Modules to control elements, pumps, etc in my brewery.
- It would have circuitry to enable the reading of many 1wire temperature sensors – that is, a pull up resistor on GPIO 4 (Data or DQ pin typically used for interfacing DS18B20 temperature sensors with Raspberry Pi), and 5V and GND break outs.
- A decoupling capacitor, and a big ol ground plane, intended to improve the quality of the 5V power supplied to the Raspberry Pi and reduce electrical interference respectively.
- Screw terminals for everything to simplify installation.
My initial PCB designs were done using Fritzing software, which is very user friendly, and opensource, but development on it has dropped off – the last release was in 2016. As I gained more experience I’ve switched to using KiCad software which offers more advanced features.
I’ve gone through a couple revisions of this to minimize the footprint and implement small improvements. I’ve been using this board for over a year now quite happily. The full design (and history of the design), as well as bill of materials can be found on github here. The design can also be downloaded and ordered from PCBWay here.
The design… the top anyways!
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