ir emitter/detector circuit

[gnomeman]

ir emitter circuit

Hi gang, I need your help again.
I'm using this simple ir emitter/detector circuit.

Normaly, the circuit output is 5 volts, when the detector detects the ir light, the voltage goes to 0 volts.

My question is: Is there a simple way to reverse this? In other words, I'd like the voltage to be normaly 0 volts and when the detector detects the ir light, the voltage goes to 5 volts.
Any help would be greatly appreciated.
Thanks
Bill

 

[cameo_2007]

ir detector circuit

which is that transistor and what is the 'Vce' of it?
if you are ok if you get say for eg 3V instead of 5V,
then interchange R2 and T1.

so when does not detect ,Vout = 0,
when it detects , Vout = Vcc - Vce (vce normally used to be 2V)

-cheers

 

[gnomeman]

ir emitter schematic

Cameo, not sure what you mean by vce? I'm new to electronics and am trying to learn.
Ir led and the phototransistor are the pair that radio shack sells. With the circuit I'm using, it senses an object at about 6 to 8 inches depending on room light conditions.
I did change the resistor values from what the schematic calls for.
The schematic calls for: R1= 270 ohm- R2= 10k.
I ended up using: R1=56 ohm R2= 25k
I know that the output voltage of 5v will not run a small motor but will light a white led dimly. Knowing this tells me that the output has voltage but not much amperage. I use the white led in conjunction with a dark sensing relay circuit to reverse the motor on one of my robots.
If I could get the ir circuit to output voltage when it senses an object, then I could continue experimenting and maybe boost the output enough to work a 5v relay.
Any way, I will try what you suggested and see what happens.
Thanks
Bill

 

[gnomeman]

ir emitter detector

cameo, switching r2 and t1 did the trick. I now have normaly 0v and 4.9v when ir light is detected.
Now I have to figure out how to boost the amperage so the 5v output will run a small motor or triger a relay.
Thanks again cameo
Bill