Hi everyone.
I'm trying to control a relay with Sharp IR sensor

Relay and sensor can be powered by 5V. The problem is that sensor's output varies between 0.2V-2.5V (depends on distance from reflective surface) and this is too low or too high for transistor's base.
Any other solution?
Thanks for any help.

 

What is the part No? Or do you have a spec sheet?
Often these retro-reflectors are Open Collector and switch 0-5v, unless the output is directly from the sensor itself.
Max.

 

Using comparator as LM393 and to set a reference voltage as 0.2V or othe r voltage you want, LM 393 needs a 10K pull up resistor, this is a trigger signal.

1. Adding a NE555 monostable to get a delay time.
2. Adding a CD4013 flip flop to get a toggle switch.

If the current of relay less than 70mA, then ne555 can sink or output the current, if you using CD4013 then you have to using a bjt to drive the relay.

 

What is the part No? Or do you have a spec sheet?
Often these retro-reflectors are Open Collector and switch 0-5v, unless the output is directly from the sensor itself.
Max.

Here is data sheet

http://www.sharpsma.com/webfm_send/1542

Thanks Max

 

how about a comparator with an adjustable reference from a pot, so you can adjust the trigger distance?

 

You really need a N.O. or N.C. type output, with analogue type output you will need one of the solutions already mentioned.
Or a LM311 comparator set for the minimum signal.
Max.