IR sensor

Ntelos

Hi there!

I designed a circuit (on a breadboard). The circuit consists of an IR led - as a transmitter and a TSOP1740 as a receiver. I want to insert the IR transmitter in a small room, but because of the walls the receiver detects signal all the time. The one pin of IR led is connected to an input in basic stamp 2 (on/off function) and the other pin is connected to an input through a 430 Ω resistance to another input in basic stamp 2.

What could i do so the signal does not detect the walls as an obstacle? Or how could i reduce the emitting distance of the IR led?

Thanks in advance

Mike Green

You could increase the value of the resistor. That will reduce the current which will reduce the intensity of the IR produced. Get a 5K trim pot, preferably one with that takes 10 turns of a screwdriver to go from 0 Ohms to 5K Ohms. Use the 430 Ohm resistor in series with it (so you can't accidentally drop to zero Ohms), then slowly increase the resistance until the range is more like what you want.

Ntelos

I used a 5K trimmer and it worked (at about 2.7 KΩ so it can detect at 2cm's distance).

Thank you very much for the solution!