Web cuffs

[justDIY]

A rather old idea, finally close to complete

web cuffs

Network / Internet controlled self-bondage cuffs / shackles

A plastic plumbing tee holds a pair of round electromagnets, designed to hold fire doors open.

The center where the wires are coming out will receive a short tube to contain the circuit board and battery. I'm using a small radio control 12v battery. I would like to upgrade to an 18 or 24 volt battery, to increase the strength of the magnets... right now the holding strength is about 60 lbs, which I can easily pull apart.

The circuit board has two switches, one for the magnets, one for an accessory, like a vibrator, enema water pump, e-stim trigger, you name it.

web cuff control 1

web cuffs control 2

The programming is simple for now. The lock has three modes and the accessory has four.

Lock and accessory modes:
1. Manual Control - On until someone turns it off or the battery dies (magnet at least 8 hrs) with this little battery.
2. Time Duration - On for a set time (in minutes), turns off automatically
3. Time Interval - Cycles on/off for a set time on, set time off

Accessory-only mode:
4. Random - Cycles on and off randomly constrained by minimum and maximum time

It cost about $120 to build, most of it being the magnets... need to find a cheaper source for this diameter magnet.

[DrPerVECT]

Just a thought: electro magnets are current-driven devices. Although a higher voltage battery might push more current through the magnet, have you considered DC2DC conversion or using an inverter and a transformer to raise the current? It might make the magnets stronger.

[Area51]

Very cool, can you give a rundown on the hardware you used and where to get it?

[Leopard99]

Just a thought: electro magnets are current-driven devices. Although a higher voltage battery might push more current through the magnet, have you considered DC2DC conversion or using an inverter and a transformer to raise the current? It might make the magnets stronger.

All electromagnets are indeed current driven devices. But all have resistance (unless you're dealing with superconductors which are bit out of our league), so to drive the current you need voltage, all according to Ohm's law. It doesn't matter how you get that voltage, whether by a bigger battery or some clever electronics. Unfortuantely there's a little thing called heat. The power dissipated in the magnet's coil is equal to voltage multiplied by current. If you push up the voltage and/or current at some point the coil will get too hot. If you're lucky it will just fail open circuit. If you're unlucky it will set fire to something.

It's all a bit more complicated if you're using AC rather than DC (eddy current losses, reactive power etc) but heat is still heat.

Whatever setup you're planning to use, give it a realistic test while you're not locked into it. For an electromagnet based device just run it for the longest period you might be locked in it and see how hot it gets. A smell of overheating electrics is bad enough if you're free and able to deal with it. Not at all funny if you're locked up at the time.