Instructables

electronics remote control

could anyone suggest how to build an electronic system for using a radio signal to turn on and off another circuit. what i mean is a transmitter with a button you could hold and press a switch and a reciever in the circuit you want to switch on and off which prevents power reaching the circuit unless you are transmitting. i would want to be able to transmit over atleast 20 metres and through thin walls, aluminium foil and clothing. thanks.

Check out Ebay. Search for remote control relay. You can find everything from 1 to 4 channel units. A one channel unit that will reach at least 30 to 50 meters cost about $10.00 and operates on 12 vdc.. They all come with small key chain remotes. I used one of these on my remote control coffee maker and it has worked great for a couple of years now. Foil should not be a problem unless it completely surrounds the receiver unit and is grounded. The receivers do have small coiled wires that serve as an antenna. You could easily put a hole in the foil and stick the antenna wire through it for an external antenna. Best of luck.
cbm1042 years ago
As Caitlinsdad said, radio could be shielded by the foil, if you have a couple of bluetooth phones you could test it but I suspect the range and shielding would be prohibitive. Light (eg. infrared) would be easy to use with an Arduino but blocked by the walls.
If your remote will always be in the same place then a long wire is easiest for a guaranteed-to-work solution. However as you are passing through clothes i'm guessing mobility may be required. So how about ultrasound? It should pass through thin walls, aluminium, and clothing. A quick google finds lots of ultrasound rangers,they seem to go up to 5-6m but that is sending a signal and receiving anything which has bounced back. It doesn't seem unlikely that only a small fraction of the transmitted ultrasound is bounced back to the receiver so the range of a separated transmitter/receiver would be more than double. Might not be 20m through walls though?
i'm looking for a cheap option, going through walls is not really necessary but would be nice. i was thinking about having the transmitter hidden in my pocket so i could control a circuit elsewhere in the room. the aluminium foil is mentioned because the circuit will be inside a thin walled metal box, i do not think i could mount the receiver outside this box but it might be possible. i am not great with electronics so think i might be best off salvaging the circuitry from somewhere else. this reply is aimed at caitlinsdad as well as yourself. thanks.
caitlinsdad2 years ago
Aluminium foil would block or interfere with most radio signals... You might want to look into an arduino with Xbee shields, a microprocessor with wifi or bluetooth signal transmitters and receivers to control your circuit. A radio system from scratch might be difficult. Good luck.