Progress of my Arduino-based projects and other Arduino news that floats my boat
Monday, July 25, 2011
(F)Light Suit Progress: PWM!
I had a frustrating time trying to get a PCA9685 working-- it wouldn't even reply with its register byte values. I've interfaced with other I2C chips and didn't expect problems, but trouble was all I got.
Poking around the Arduino Forum trying to find any examples with a PCA9685, I found the thread on Elco Jacobs' new ShiftPWM library to drive the outputs of the ubiquitous 74HC595 shift register with 8-bit PWM precision. His demo video is on the right. The example sketch was so straightforward, I had two chips driving-- and dimming-- 16 red LED's in minutes.
Once I saw those red LED's cycling, I considered that part of the project done-- thank you, Elco!-- and started laying out a driver board with a 74HC595, eight outputs hooked up to MOSFETs and test LED's, and screw terminals so they can be daisy chained. With the DorkbotPDX order deadline this morning, I had to stay up late laying it out and getting a final Eagle brd file ready, and hopefully it will work; I wasn't that excited about asking for six copies of a 3.9"x2.1" V001 design and having no time for a second run if they don't work, but... hey, they'll work!
Here's the Eagle schematic: pdf, sch.
And the board: pdf, brd.
There was a problem with the panel my board was on so it's taking a little longer than usual, but I'm hoping to have them by next weekend-- the soonest I can build them out anyway, so not a big deal. The suit electronics programming is going very well-- can't wait to get it all together and present it! I'll post details the last week of August or the second week of September.
Hi,
ReplyDeleteHow did your dorkbot PCB's turn out?
I ordered mine with the 1 Aug batch, I will probably get them in a week. Excellent service for a very good price.
Looking forward to see your finished suit!
There was a problem with the panel my board was on so it's taking a little longer than usual, but I'm hoping to have them by next weekend-- the soonest I can build them out anyway, so not a big deal.
ReplyDeleteThe suit electronics programming is going very well-- can't wait to get it all together and present it! I'll post details the last week of August or the second week of September.