Finished the VU. Changed the name to a 32 LED Driver as that is what it really is. The idea for the VU is to sample the sense line via an ADC a couple times and average the value. Then the MSP430 will look up that value on a table and light up that many LEDs. Should be fairly straight forward.
Great project! Looking forward to seeing it alive! However, there are a few things about the PCB that I am curious;
1. If this is not going to be a home-made PCB, and it will be double-sided with silkscreen, then, why didn’t you fill bottom layer with a ground plane? That would be better!
2. Would it look better if all of the labels were in the same direction?
The bottom and top both have ground fill. I just had it turned off for the picture as it is hard to see what is going on with it displayed.
The labels are running two directions depending on the orientation of the part. The only one that deviates from this is the “sense” pins. I will probably rotate it.
Ah, couldn’t notice that ground plane, that’s great if you have them. About the labels, you should put them ALL in one direction so one can read them without turning his/her head. That is my two cents though.
Hmm, what is wrong with the various bargraph drivers like LM3914? (good project here: http://www.eevblog.com/2011/09/29/eevblog-204-designing-a-li-ion-battery-gauge-with-the-lm3914/)
It is a lot cheaper and requires fewer components than using a micro + expanders for driving the LEDs.
Cool! Never knew that existed. Saving that datasheet for future reference. I wanted microcontroller support so I could run through different light modes (all on, chaser, ect). Probably could easily do this with a small PIC but I already have lots of MSP430 stuff lying around.
The bargraph drivers have usually two modes – a bar and a running dot. Micro is, of course, more flexible.
BTW, those chips are from the 70s or so …