Step 6: PCB Design

Picture of PCB Design
The Pingbot uses a single sided circuit board with wire jumpers soldered underneath. It was made with a type of circuit board that is coated with a light sensitive film, a devolper for that film, ferrite chloride to etch the board, and a tining solution kit. The components were then soldered to the board by hand using a fine tipped soldering iron.

Drawing the Circuit Board
Using Adobe Illustrator I created different layers for the traces, components, the grounding plane, and the part labels. Using the component's data sheets as reference I then drew out all the components to their actual size and arranged them to fit within a 37mm diameter circle. Traces were drawn according to the schematic to connect the components.

I used Illustrator because I am familiar with it, but the most common way to design circuit boards is Eagle PCB, a free software from Cadsoft . This program can be used to draw out a schematic that can be converted into a PCB layout. The designs and files that it generates can be printed out or sent to a manufacturer to be fabricated.

Charge LED, I'm Doing it Wrong
While designing this PCB I had assumed that the MAX1555's charge LED should be connected to ground. After I had finished soldering I did some testing and found that the LED wasn't doing anything. It should have lit up when the robot was connected directly to a USB port and the battery was charging, but that didn't happen. Turns out the LED should have gone to +V...

To fix this I desoldered and lifted the LED's lead, the one that I thought went to ground, from the PCB and connected it to +V with a jumper wire above the board. I stuck a dab of hot glue under this LED to make sure the lead didn't touch the ground pad. This error was corrected in the schematic, but I have not fixed it in the PCB layout. Instead I've just shown the jumper wire.
Do you have a larger version of the PCB and Schematic I can download from somewhere? I am having trouble making out the writing. Cheers!
Tomdf (author)  IBreakHeavyStuff3 years ago
No problem at all. Hover your mouse over the image and in the upper left hand corner you will see a small white box with an "i" in it, click that box. when the next screen pops up you will see the image and right under it will be something like this: "original file: (1942x2383) 375 KB"
Click on that and you will be able to download the full size image.
Oh, thanks - found it. I don't suppose you have the original Illustrator file (clear - without the components drawn in) so I can use it to print off a PCB?
Oops, never mind. Just found this:

Thanks for all your help. Now I know how to look at different pictures too. I look forward to seeing more of your work - this is awesome!
Ah - Turns out I do need your illustrator file if at all possible???