I have a simple digital logic circuit using xor gates and a few inverters that basically triggers an attached LED to come on. What I am looking to do is somehow trigger an led wirelessy to come on when the output of my digital circuit is high. What could be used to do this correctly. the distance between the circuit and the LED would be a foot or two.

Eric

 

Use an IR LED to send a high, use a phototransistor to receive it. You only really need the phototransistor, current limit resistor for the LED and the LED on the receiver and a DC voltage.

The transmitter needs a high source and a current limit resistor for the IR LED if the digital output can source voltage. It has to be wired differently if it can only sink voltage.

 

There is no line of site between the transmitter and the reciever, so I would need to use something else other than an IR transmitter. Anyone have any other ideas?

 

ekafrawy,

A very cheap RF remote control can be created by modifying a micro RC car transmitter and receiver. Sometimes you can find these for less than $10US. The transmitter has 4 buttons: Forward-Back-Left-Right. These could be interfaced with your logic. The receiver has two open-collector outputs and an H-bridge (I think) output. 8 possible output combinations of single or double button presses are: F, B, L, R, F/L, F/R, B/L, B/R. I've used one for a remote control gag gift, and was able to get about 12 feet range with a longer wire on the receiver than the original car.

Ken

 

basically all i want is if the transmitter gets a High input signal(+5v) then the reciever should output the same high(+5V). Can i get a specific part# or website that could supply these? I thought this would be pretty staightforward.
thanks

 

eric,

I just posted a logic interface for a Radio Shack 49MHz ZIP-ZAP (not an SE model) car receiver on another thread:

http://forum.allaboutcircuits.com/showthread.php?t=8515&page=2.....#14 post

All you would need is the output circuit for the Left (R5, R9, R11, and Q4), and put your LED in series with R9.

I haven't done anything with the transmitter, but the buttons just pull 3v logic lines to ground, so it could be done with a single transistor and a resistor to an external logic circuit.

Ken