First Homemade PCB – Binary Dice
I had an interesting evening last night. I gave this another go but using my own art work for a simple binary dice that I designed a few months ago when I was just getting to grips with EasyPIC6, Microcontrollers and Mikro C. It is only simple, you press a button and it gives you a ‘random’ number between 1 to 6, displaying it in binary. It also has a simple circuit so with little effort I could make it on a one sided PCB layer with no jumpers. I really need to learn how to use the polygon tool to make a ground mask but I couldn`t get it to work and was despirate to give the pcb making process a try…another ‘something’ for next time.
This was the design. I`m sure it could be a better layout. I started off during the last week learning how to use CADsofts EAGLE but I found it a real PITA. I must have clearly been using it incorrectly but I found the schematic layout fine but actual laying traces seemed so rigid, I just couldn`t get it to do what I wanted it to! I then tried the free version of Proteus, – Proteus Lite and it was excellent. It only took me a few hours and I had nearly designed my board:
I then printed it off, exposed my copper board it for 3 minutes in my UV box, developed for 1 minute and started etching:
Then to the part I had feared. I actually thought I was going to leave it there as I didn`t have a drill that could run at 5000rpm or great. I came across this which had been given to me at a shop clearance, it came in a little box with tiny drill bits and I knew the guy who owned it made pcb’s as he had a UV exposure unit (didn`t know what that was at the time!). It says 10.5v on the front so I plugged it in DC 10v and expected it to fly around – it went quite slow, relative to what I was expecting and certainly not 5k RPM!! Anyway, I couldn`t go any further as I had no drill stand, then I realized it was small enough to clamp in my milling machine. With little effort a 0.8mm drill bit went straight though and was very accurate. I experienced no snapped drill bits or wandering holes. The only issue was that the drill had very very little torque and consequently grabbed twice and got stuck so I had to twist it off.
Here is the board with components soldered. You don`t get a peak at the back side now as my soldering has a little to be desired!
It got late when I had finished and need to re-programme the PIC with the correct pin for the button and then should give it a test. I may have done something wrong on the board design but the concept of making a PCB at home has worked! Next time I need stronger tracks but as I mentioned above, I think doubling up the artwork transparency will help a great deal as there are currently clear areas of the track that are not sharp enough. Practice I guess..