Hi and a HNY to all,
I am still doings bits on an Arduino driven model train project for my BIL and last night I had a loco shuttling up a test mainline track and back via a little runaround loop (with two sets of points working in parallel).
I was testing driving the 'solenoid' type points / turnouts using a 2A (3A peak) 'Dual H bridge' (very cheap on eBay):
https://preview.tinyurl.com/lktzzp3
and a pair of diodes and a capacitor to ensure the solenoid coils aren't burned out. The circuit looks like this:
**broken link removed**
My question is please, should the back-EMF diodes that are on the bridge module itself be sufficient (to protect the bridge IC), or would it also be prudent / possible to fit some additional diodes, like this? Or maybe because of how the circuit works they aren't needed?
**broken link removed**
If it will still work with those additional diodes in place, I was thinking of making a 4 - way PCB that would go between the H bridge and the points and I could fit all the components on there (in case I use an H bridge that doesn't have them fitted), rather than nearer the points themselves, as I (or another) might (accidentally) wire the points a different way round and thefore the diodes could end up being fwd biased.
All the best for 2015 and thank you for your time in any case. ;-)
Cheers, T i m
I am still doings bits on an Arduino driven model train project for my BIL and last night I had a loco shuttling up a test mainline track and back via a little runaround loop (with two sets of points working in parallel).
I was testing driving the 'solenoid' type points / turnouts using a 2A (3A peak) 'Dual H bridge' (very cheap on eBay):
https://preview.tinyurl.com/lktzzp3
and a pair of diodes and a capacitor to ensure the solenoid coils aren't burned out. The circuit looks like this:
**broken link removed**
My question is please, should the back-EMF diodes that are on the bridge module itself be sufficient (to protect the bridge IC), or would it also be prudent / possible to fit some additional diodes, like this? Or maybe because of how the circuit works they aren't needed?
**broken link removed**
If it will still work with those additional diodes in place, I was thinking of making a 4 - way PCB that would go between the H bridge and the points and I could fit all the components on there (in case I use an H bridge that doesn't have them fitted), rather than nearer the points themselves, as I (or another) might (accidentally) wire the points a different way round and thefore the diodes could end up being fwd biased.
All the best for 2015 and thank you for your time in any case. ;-)
Cheers, T i m