receiver tk19 749
Here are some things to keep in mind.
1. Both emitter and detector shoul be rated at the same wave length and the detector should have a IR filter to keep response from ordinary light down.
2. Drive the emitter with the full rated current.
3. The amplifier following the detector should be of the transconductance type. Use an op amp with the + input to ground, a resistor from the output to the - input and the detector diode from the - input to a supply voltage. This should be oriented so that the diode is reverse biased.
4. There may be pick up of the light from artificial sources operating from the utility mains. Check for this in your receiver. Two ways to get around this is to use physical barriers to keep the lignts from shining directly on the detector. The other is to use a high pass filter (series capacitor) after the first amplifier stage and use a signaling scheme which does not have any low frequency components. One of these is to use FSK. Exar compnay makes many good ICs in this area.