Wow, a long time with no posts – sorry about that!

I have been busy the past week, I wanted to take Thursday and Friday off, so I had to cram a weeks worth of work into the first three days.

I’ve also been racking my brain, trying to figure out how I can integrate a matrix wired LED array into my sensor project. I think I’ve come up with a solution, partly hardware, partly software. Originally I had wanted to have all the LEDs on, and turn them off to do a measurement. This created a lot of problems, mostly due to the current demands. Well, I think I can achieve the same goals, without having all the LEDs lit simultaneously, which will reduce the current demands and should simply the circuit a little.

There is the PCB layout for my latest design… I think I’ll make one to test out, and if it doesn’t work for my sensor array, I can use it as a mini marquee. Sixteen vertical columns, anode connected, each driven by a 74HC595 serial shift register. Seven horizontal rows, cathode connected, each driven directly by the PIC’s analog input / digital output pins. To keep current demands low, I will only illuminate one column at a time. I think that still exceeds the design recommendations of the 595, but heck, its all I can think of at the moment.