I am attempting to build a small IR blaster, for use outside. The idea is there will be one receiver and multiple transmitters, each sending a different ID.
The transmitters will constantly transmit with a repeat of something very short like 45ms. They will be moving, thus only detected as they pass the receiver.
The receiver will be mounted in a tube to reduce glare from the sun and to aid directional detection. I plan on using a simple protocol like the Sony IR one, which I have already implemented.
I am trying to mock this up on breadboard so I can see what speeds realistically the transmitter may pass the receiver at in order for reliable detection. Distance for transmission is actually quite short, probably maximum 2 metres.
My question concerns the receiving method. Basically my choice seems to boil down to:
I bought a bunch of photodiodes thinking they would be the best solution, but obviously they don't have a logic level output. When they detect, a very small current will flow. They are fast, but would require coupling with a transistor.
Advantages of the phototransistors seem to be logic level output (straight to my uC) and no need for a carrier, e.g. 40Khz.
Advantages of the TSOP receivers seem to be the in-built filtering and amplification. In addition, a 1/4 or 1/3 duty cycle signal on top of a 40Khz carrier would actually reduce power requirements. This makes the transmitter software marginally more complex.
So does anybody have any recommendations what to choose? I have never used any of the three, so would welcome ideas on which might work best.
The transmitters will constantly transmit with a repeat of something very short like 45ms. They will be moving, thus only detected as they pass the receiver.
The receiver will be mounted in a tube to reduce glare from the sun and to aid directional detection. I plan on using a simple protocol like the Sony IR one, which I have already implemented.
I am trying to mock this up on breadboard so I can see what speeds realistically the transmitter may pass the receiver at in order for reliable detection. Distance for transmission is actually quite short, probably maximum 2 metres.
My question concerns the receiving method. Basically my choice seems to boil down to:
- IR photodiodes
- IR phototransistors
- TSOP IR receivers
I bought a bunch of photodiodes thinking they would be the best solution, but obviously they don't have a logic level output. When they detect, a very small current will flow. They are fast, but would require coupling with a transistor.
Advantages of the phototransistors seem to be logic level output (straight to my uC) and no need for a carrier, e.g. 40Khz.
Advantages of the TSOP receivers seem to be the in-built filtering and amplification. In addition, a 1/4 or 1/3 duty cycle signal on top of a 40Khz carrier would actually reduce power requirements. This makes the transmitter software marginally more complex.
So does anybody have any recommendations what to choose? I have never used any of the three, so would welcome ideas on which might work best.