View Full Version : Split 595's - Reliability Issue?

02-04-2008, 10:01 AM
I've been running my display lights all from 1 595 board that has 32 channels. I put it together myself, not using any of the premade boards. Knowing I wanted to run it all off of one board, I didn't put in any expansion headers.

This year I have to remake the board (for numerous reasons), and some of my displays are going to be further apart. I was thinking about splitting out each of the 8 channels per 595 on their own little board, and link them all together, so they'd be closer to the individual display parts (to save on cords). I'd have probably 4 boards this year that will be daisy chained.

Anyone see an issue with this? I know it was designed for this type of expansion, but I don't know to what extent. Think there'd be any reliability issues?

02-04-2008, 10:48 AM
You ma run into voltage issues with your control signals if you remotely locate the 595 chips. The 595s work off a high signal or positive voltage. Their trigger voltage is directly related to the supply voltage as their reference. The issue you may run into is that you supply the chips with 5 volts but by the time the control signal gets out to the chip from all the cable in between your voltage may drop and not been seen as a high since the resistance in the wire has dropped the voltage.

The 595 should be kept in a relatively close proximity to the controlling pc.

You may be interested in the 595 coop I just posted about in the Coop forum.