Want to make a 14 channel transmitter and reciever any idea'

RF control

I am just putting together a radio transmitter and receiver to control some camera gear - I'm using a microcontroller to read and encode a 7 by 8 keyboard matrix and send an RS232 code to the radio transmitter. The receiver passes this code to a second microcontroller which decides what the code means - energising one of 18 relays or sending a command string to a video multiplexer via an RS485 link. I am hoping to get a range of about 100 metres out of the radio link when it's finished (through walls and trees).

The radio modules I am using are from EasyRadio (they take RS232 directly, nice and easy, and LEGAL in the UK and Europe)
**broken link removed**

This sounds something like whay you want ? to add an analogue joystick would just mean a bit more code for the microcontroller to read its A to D port. I only need to transmit a keycode when a key is pressed or released, you may want to transmit everything 20 times a second or something - depending on robot speed, accuracy, amount of data you want to send ???

reply

I want this to be protable, like a handheld device and nothing to big.

I am limited on space.

What you could do is buy two FRS radios (they have exactly 14 channels, but you will only need one) off of Ebay (You can get them for REALLY cheap).

Next rip their insides out so that they take up less space. Then, if you are using a microcontroller, you can use the microcontroller to send DTMF tones through the radio (i.e. hook the PIC up to the mic in jack, or to the actual internal microphone).

You have DTMF tones 0 to 9 which you could transmit over the radio and each tone could represent a different command. If you wanted more commads you could use more than one DTMF tone at a time.

On the recieving end you could hook a second microcontroller up to the second radio's speaker out jack (or just take the two wires that go to the internal speaker) and program the microcontroller to do whatever depending on the DTMF codes.

I also suspect that there is a way (though not readily apparent to me) that you could simply send RS-232 over the radio.

I hope I've been clear and that this is helpfull. If you have any questions e-mail me at: micah.hurd@gmail.com