For a long time now I’ve been wanting to make my own microcontroller-based prototyping board. My original motivation was the unjustified high costs for even the simplest boards (a basic Arduino for $30 – why???) and the challenge of designing something that anyone can make at home within a few hours, with parts that can be cheaply obtained on eBay.
Eventually, I came up with the PICMAN. It is:
- Based on Microchip’s PIC18LF4553 – a 12MIPS microcontroller with 12-bit A/D, plenty of I/O, built in USB transceiver and tons of other coolness.
- A single-layer PCB design – ideal for DIY toner-transfer etching fabrication.
- Small form-factor that nicely fits on a solderless breadboard.
- Can be powered by USB/external 5V/external 8V-35V using on-board 1.5A regulator.
- Has a reset button, a user button a power LED (blue) and 3 user LEDs (red, yellow, green).
- Needs zero external components to work.
- Programmed with a bootloader, making it possible to download a program via USB.
- Can implement any USB device using Microchip’s USB stack.
- Less than $7 total with easily obtainable parts (not including shipping costs, which are usually low if not free, and assuming that some of the small parts are bought in quantities).
I made two pieces so far, each took a couple of hours’ work, requiring some SMD soldering experience. I did the initial programming (bootloader image) with a PICKit2 programmer, after having to struggle a little with the Microchip provided bootloader firmware code. It really works nicely – I like it much better than most Arduinos that cost 5+ times as much and it was really fun to build.
Some ideas that I used in the design:
Some ideas that I used in the design:
- Mount the PIC at the bottom of the board, between the header pins.
- Use the copper layer for text to make it easier to locate individual pins.
- Use a mini-B USB connector for smaller form factor (than B) and availability of cables.
For more detail: PICMAN prototyping board using PIC18LF4553
