IR Proximity Sensor

[jada88]

Hi I realise that this thread is a bit old, but on the 25June 2011 post no 28 Eric Gibbs posted a circuit, and I want to know if I need permission to use it? If I have permission to use the circuit I will post mine for your comments and advice.

jada88

 

[ericgibbs]

Hi I realise that this thread is a bit old, but on the 25June 2011 post no 28 Eric Gibbs posted a circuit, and I want to know if I need permission to use it? If I have permission to use the circuit I will post mine for your comments and advice.

jada88

hi,
No problem, any circuits I post, anyone is welcome to use them.

Post yours.
E.

 

[jada88]

Thank you for your quick reply Eric. I will post circuit soon.

 

[jada88]

Following on from yesterday here is the circuit.

View attachment 67183

 

[ericgibbs]

Following on from yesterday here is the circuit.

View attachment 67183

hi jada,
I will look it over, let you know.

Any particular section you are having a problem with.?

 

[ericgibbs]

hi,
The lines marked in Red are incorrect.

E.

EDIT:
A couple of questions.
Do you want to detect a 'beam' break between the emitter and photo diode.?
If yes , what is the shortest break time.??

Actually the circuit is not a IR 'proximity' sensor, its either a beam break or make sensor.??

E.

 

[jada88]

Hi Eric
I think the circuit is a break beam. It is in connection with another post I did about a bathroom mirror IR failure. How do I switch on the SSR?

 

[ericgibbs]

Hi Eric
I think the circuit is a break beam. It is in connection with another post I did about a bathroom mirror IR failure. How do I switch on the SSR?

hi,
I have read thru the other thread, I see that when you pass/place your hand in front of the sensor the light is activated.? is that correct.?

If yes, then I suspect that the IR emitter is pulsing at say 38KHz ??? , so when you place a reflective surface [ your hand] the IR pulses are reflected back into the IR detector.

Its also possible the original circuit works with the emitter in a continuous mode, ie DC drive, the detector senses the illumination level of the IR signal.

So under normal conditions, ie: no reflected IR , the detector will not have an output.

I would say the circuit you have posted will not give the result you expect.

E.

 

[jada88]

Hi Eric
Thanks for your advice. Yes when you place your hand in front of the sensor the light is activated. I have spent a lot of time on line trying to find a circuit so I can make a pcb to replace the original unit. Not very happy with a transformerless unit. Perhaps you can point me in the right direction.

 

[ericgibbs]

Hi Eric
Thanks for your advice. Yes when you place your hand in front of the sensor the light is activated. I have spent a lot of time on line trying to find a circuit so I can make a pcb to replace the original unit. Not very happy with a transformerless unit. Perhaps you can point me in the right direction.

Hi,
Look at this basic circuit, it uses a MOC Triac and SCR, your MOC Triac would work without the SCR, the mains circuit shown is for an SCR.

If you decide to use this method, the circuit needs to be finalised.

You dont need the 12V
E

 

[jada88]

Hi Eric
Thanks for the circuit. I take it that it uses a photo-diode for sensing, could I still use the OPB702, if not what photo-diode would you recommend? Would a C106D Thyristor be suitable to use in this circuit for the SCR? In the circuit it has LIGHT R11 1000 is this the load (1000W).

 

[ericgibbs]

Hi Eric
Thanks for the circuit. I take it that it uses a photo-diode for sensing, could I still use the OPB702, if not what photo-diode would you recommend? Would a C106D Thyristor be suitable to use in this circuit for the SCR? In the circuit it has LIGHT R11 1000 is this the load (1000W).

I would not recommend using a 4Amp C106 on a 1000W Tungsten lamp load, you should consider a 8Amp rated SCR, with at least a 40Amp surge rating.

The actual HOT lamp resistance is approx 53R.

 

[jada88]

Hi Eric
The circuit only powers a LED converter 240VAC in 24VDC out 0.625A. Will the OPB702 work with this circuit.

 

[ericgibbs]

Hi Eric
The circuit only powers a LED converter 240VAC in 24VDC out 0.625A. Will the OPB702 work with this circuit.

The OPB702 d/s shows a optimum distance of only 0.15inch for the reflecting surface.

At what typical distance did the 'old' sensor work.?

 

[jada88]

To switch on the mirror led the distance was aprox 15 to 50mm from the front of mirror.

 

[ericgibbs]

To switch on the mirror led the distance was aprox 15 to 50mm from the front of mirror.

Looking at your other thread I would say the IR emitter is pulsed operation, not DC.

This would give a greater sensing distance and also reduce the problems due to ambient light.

My option would be to find the problem with the original PCB.

 

[jada88]

Hi Eric
Thank you for your advice and time, I will see if I can find the problem with the original PCB.

 

[ericgibbs]

Hi Eric
Thank you for your advice and time, I will see if I can find the problem with the original PCB.

What test equipment do you have.?

Be aware the PCB does not have mains isolation, so it could give an electric shock if handled while plugged in.

E

 

[jada88]

Hi Eric
I have a Multi meter ( not the £5 type ) ,ISO-TECH ICT76 meter and a PicoScope 2202. However I have no idea how to use the scope yet, I will have to look for a tutorial. I fully understand the safety implications regarding mains electricty, that is one of the reasons for new circuit with a transformer.