Evolution.jpg (1641374Bytes)
Just had a rummage through one of my boxes and found *most* of the different revisions of the board that I use as my main controller, just thought some of you might be interested in how things evolve as needs change.
On the far left was my very first PCB, with a PIC16F88, a dual h-bridge, RS232 interface, ADC, Current Monitor and Tri-colour LEDs,
Next was a very 'analog' version, this time with a PIC24EP256, two dual h-bridges, real time clock, sd card and 10 channels and USB.
Thrid is another attempt, this time with protection against short circuits etc, added bluetooth short range, dual can, dual lin, dual RS232. Note the two much bigger 30A hbridges now :)
4 and 5 are the wrong way around, as you can see the strappng on '5', when I discovered that my adc's were backfeeding through the hbridge power supplys and causing noise. The solution was to add some diodes on the hbridge inputs and buffer the adc inputs. Changed to a dsPIC33EP256
Six, a bottom up redesign of the board, now with RELAYS too :) added programmable voltage outputs, more capacitance for the h-bridges, changed to a 100meter bluetooth module, added some port expanders, onboard temp senders, quad encoder inputs - 2 PICS now with a high speed data bus between them, forgot to connect some of the wires (expensive mistake) so more strapping.
Se7en, this is currently the current state of play, all of the above goodies, some more protection, better filters, more I/O and dual 16-bit dsPIC33EP512s running at 70MIPS each (280MHz PLL).
Obviously this is not designed to be a robot controller, but it really does a great job of it.
I think the point of this post is that with some effort and determination cool things can happen. I would also like to point out that I was a complete noob at electronics when I started this project (I used to manufacture windows and doors), so any can learn this stuff too. :)