Using OpenGrab as SFX

Hi! I’m interested in using the OpenGrab as a theatrical special effect. We’re trying to make a prop shelf fall on cue while out on stage away from anyone. My thought was to find some sort of “always on” magnet and trigger it with a DC relay via Arduino to “OPEN” the circuit and make the shelf fall. Would this OpenGrab do the trick? Is it as simple as sending it a 5V DC signal to OPEN this circuit and break it’s magnetism?


Hello Marcelo,

Sure may I suggest to use PWM signal, there are plenty of tutorials for arduino and the like. The EPM works just like a regular RC servo with 3 states


Thanks for the info!! Any idea any other location to purchase the OpenGrab? There’s got to be some place other than Amazon…

Yes we sell on Amazon as well; … qWzF&psc=1

Marcelo, you can order it from NicaDrone here … er=product

I just checked out their website - Thanks!

I sent them an email - I need to get (5) magnets in my hands by next week though… I hope they have more product in the US!

Thanks again!

Got my toys!!! Thanks! Having trouble activating the magnet. It appeared in the video that it was just energized with voltage. Do i need a PWM to activate the magnet?

Currently it’s wired as follows:
7.2v RC battery > DMX relay board > Open Grab

The DMX relay board takes lighting control signal and outputs it into (3) control channels (RGB)

In theory, can’t I just activate the magnet with a battery?

You can activate the magnet using RCPWM, CAN, or a button. See … _interface