I've been looking into designing my own Arduino programming and development board after seeing Ben Heck's episode. Apologies if this is in the wrong area.
So I made a quick Schematic in Eagle using the arduino schematic from the website, I've included support for the ATTiny85. I know this isn't the first time someone has done something like this, or with home pcb manufacture, just wanted to share some of the problems I've had with this design.
So here is the final result, I don't have any form during as I wasn't expecting it to work out. I haven't tested this board as there are a number of shorts, and I don't have a reset from the FTDI header.
I Tried to keep the layout simple as my original plan was to build this on proto-board, but I only had multi core wire and trying to wire that up was a nightmare in itself. So I took the plunge and etched my own board.
I have read of three (at least most mentioned) way of etching a PCB using a laser printer 1) Photo Paper 2) Magazine Newspaper 3) Print n' Peel. So i tried all of them, one of the reasons why i think that the copper on my board appears slightly pitted, removing the toner with fine grit sandpaper. By far the worst method, Print n' Peel, with kept jamming in my printer. Photo Paper worked well, but not all of the traces transferred. Possibly my traces and fills are too close for home manufacture, I plan to have a DRC for eagle best suited for home manufacture. The method I finally used was the Magazine paper, this gave me the best results.
I used Ferric Chloride, the only enchant I can easily find in the UK without online ordering. This worked a lot quicker than I thought it would.
Thing I want to change for next time;
- Better Design board, mainly clearances with the copper fill ground. This made it almost impossible with my equipment to solder without shorting to ground.
- Maybe using Photoresist, I've heard a lot of good reviews of this method
- Solder Mask - I think this is a must, I am no expert at soldering, and it will help to make my boards look more professional.
- Drill Press - I too late found out that I don't own a dremel chuck small enough to fit my drill bits, so all of the hole on this board where done using a old school archimedean drill (not fun )
- Two sided board.
I would encourage anyone who has been tempted to design their own boards, just do it. It can be stressful but worth it.
Ultimately I want to have a process with I well works best and have a small movable workbench to make custom PCB's and solder station. As my flat is fairly small and i don't have room for a full workbench. If manage to do this I will keep the community informed
I will develop these more when i find time. I've also got a plan for this basic idea including a Raspberry pi, but too early to announce that.