Crazy idea? 3V in as a trigger?

[wandererrob]

After much mucking about trying to find a way to make a beak break trigger for the Prop-1, I've had no luck.

Tonight I had an idea, but I need to find out if it's going to do anything ugly to my Prop-1. Here's the idea...

Use the guts of a solar patio light as the trigger. It turns on when light goes away, powering a single LED off of 2 AA batteries. If I were to chop the LED and wire the leads to a couple of pins as a trigger, will it fry anything? I know the pins can put 5V out, but I'm not sure how or IF they can handle any voltage coming in.

Or for that matter, if 3V is too much, what CAN it handle? A resistor or 2 could bring that down to a reasonable level quite easily I think.

If this actually will work, this would make me a breakbeam trigger that acts, codewise, as a simple switch.

[JonnyMac]

DANGER, Will Robinson... be careful, please.

The Prop-1/2/SX can take an input up to 5v (on the W connector of the WRB header pins); anything over 1.5 volts will be seen as a "1" on an input pin.  You need to make sure that the ground side of your solar device connects to ground on the Prop-1.  Take one of our our extender wires and cut off one end.  The white wire (signal) goes to the output that's supposed to be 3v.  The black wire goes to the ground side of that circuit.  Do not use the red wire. 

Make sure you observe the WRB polarity markings on the Prop-1 and by all means make sure that the IO pin you're using is configured as an input.

[wandererrob]

Thanks Jonny. Good to know it won't fry it so long as I follow your directions. I'll post back with my results.

[wandererrob]

We have a Prop-1 Breakbeam trigger!!!  ;D


Thanks for your help Jonny! You've just made a lot of lives easier. :)