Recently I acquired some samples of IR LED's, and a matching IR Phototransistor.
I was bored, and decided to make something with it!
In order to make the transmitter, you will need
1 IR LED
2 AA Batteries + case
150 ohm resistor (1 watt, or two 1/2 watt 75 ohms)
To make the receiver, you will need:
1 IR Phototransistor, (needs to be the compliment of the IR LED)
1 Darlington transistor Or MOSFET (I used a TIP31, for the MOSFET version I used a IRFP510)
Low ohm resistor (1-10 ohms, I used 2.2 ohms)
And a small heatsink!
1 10k resistor
10k Potentiometer (also optional, allows to adjust sensitivity)
If you have a soldering iron it helps a LOT to have. It makes putting everything together 10x easier. I just made mine on a breadboard.
Step 1: Assemble the transmitter!
If you use a breadboard, just connect everything up the way I've shown below. The transmitter needs to be separate, however, or that defeats the purpose of the circuit!
The IR Phototransistor looks exactly like an LED, though it might be darker (daylight filter, so the sun doesn't turn it on though mine still had issues with it)
The transistor needs a heatsink depending on how heavy your load is, or how long you plan on running it.
I'm going to eventually try and change the transmitter to transmit audio signals, so I can have a wireless audio system! ^^
The issue with this though is that solid objects tend to block the IR.
The diode is used to prevent silly people from hooking everything up backwards (+ to negative, etc)
This circuit is pretty universal, and depending on what type of transistor you use you can make a lot of stuff remote controlled!
The Potentiometer is there to adjust sensitivity to the IR LED.
Step 2: Final NotesAs said before, this can be used for a wide variety of things. You could use it to turn on your computer, your lighting (though, you might need a beefier transistor and a larger heatsink, and a different power supply for the IR Phototransistor)
Have fun, be safe, and don't be sticking resistors in home outlets. :)
So, I figured out that the phototransistor cannot supply enough current to turn on the mosfet or darlington fast enough, so that the square wave output from the IR LED becomes misshapen. I'm currently working on a different way of getting it modulated and amplified so the speaker can be louder.
Subscribe to me, if you want to see how the next circuit I design works! :D