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).
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