Accessories - do they need a .........?

All,

I'm thinking of making my bot a cop-bot

I've made up some flashing blue and red LED's to run on 12v, along with a siren ;-) I'm looking to use a servo to flick a switch to turn the lights/siren on and off.

As they run on 12v and my drive and weapon run on 18.5v I'm going to run a seperate circuit with a 12v battery, however will these need a removable link? They are not dangerous in anyway and they will be dead with the servo/switch and when the Tx is turned off with the digital failsafe.

Also can anyone suggest a good switch that a servo can flick on and off for a 12v circuit?

ta
billy

you could just use a remote controlled switch such as a battleswitch or a turnigy one:

http://www.ebay.co.uk/itm/RC-Turnigy-Re ... 1129wt_907

They really should have a removeable link as if there is a short there is no way to break the circuit, hot batteries are never good! The way around it would be to put a small relay into the circuit. Have the coil side paralleled up to the main power circuit (ie link goes in and it is activated) with the light circuit on the load side.

jonny thanks for the switch link that would be better.

good you suggest a relay for this idea?

thanks
billy

Something like this I would imagine;

http://www.ebay.co.uk/itm/SOLDERLESS-RC ... 1c1cf5d4d8

as a relay?

To operate a switch from radio gear you need 2 things. The switch itself (relay) that can handle the current of the circuit your powering, and something to turn that switch (relay) on and off via radio gear.

What I linked you to is both of those things in a compact unit (I believe). Never had a need to turn lights on and off!

that link is a rc switch like the one i gave you the link for. i think gary's saying that you could have a relay so that when you put the main robot link in power goes to the relay turning lights etc on, when link is removed no more power goes to relay and lights etc are turned off.

Oh I see, so you could have them on a different power source.

I think any Transistor, MOSFET or relay will do that, providing the lights don't draw a huge current.

I think you can get MOSFET's from the trigger assembly on cordless drills.

mosfets would be a bit trickier as you have to match up the right voltages. Just use a car relay like this one,

http://www.ebay.co.uk/itm/PCB-Automotiv ... 2eb6b17cbd

Over rated but will happily do the job.