Quote:
Originally Posted by Chatouille
Do you mean to use the pull down resistor in case of power loss to the controller? (so that the LED’s don’t go to full power?) From what I’ve read, if you remove power to the arduino, the PWM output is already held low, and the lights will not come on. It would be a great safeguard if the physical connection is lost though, and very easy to add to the LDD boards.
Chris
|
Yes, in case if the physical connection is lost (all it takes is one loose connection). For the sake of engineering rigor and user experience, when dealing with logic or PWM values you should always use pull-up/-down resistors so that devices default to a desired state when they're unplugged. It's kinda silly for the lights to turn on 100% if you need to unplug your controller to do something, right? Imagine the amount of online bitching we'd hear if Radions did that
If the Arduino does lose power, the PWM pin should also go to ground because the -ve/ground of the Arduino is connected to the -ve of the driver, but there is also the possibility of the PWM pin of the Arduino just floating. The pull down resistors are an added safeguard in that situation as well.