Hi Albert,
With respect, I would suggest you write your response to the OP and not me.

I am fully aware of the TSOP solution, but I am trying to help the OP understand the problems with the circuit that he has been assigned by his 'prof' tutor.

Is my theory correct? But my prof. tell me the output will be "HIGH" when something between it. Or can someone briefly explain it to me

Eric

 

Hi Albert,
With respect, I would suggest you write your response to the OP and not me.

I am fully aware of the TSOP solution, but I am trying to help the OP understand the problems with the circuit that he has been assigned by his 'prof' tutor.

Is my theory correct? But my prof. tell me the output will be "HIGH" when something between it. Or can someone briefly explain it to me

Eric

OK, out.

 

Hi Albert,
With respect, I would suggest you write your response to the OP and not me.

I am fully aware of the TSOP solution, but I am trying to help the OP understand the problems with the circuit that he has been assigned by his 'prof' tutor.

Is my theory correct? But my prof. tell me the output will be "HIGH" when something between it. Or can someone briefly explain it to me

Eric

Some of my senior helped me out and it works now. But how is this even works? Can explain more details to me? The red wire from collector is connected to trigger.

 

hi T,
That circuit photo you have posted is not the same as I posted as a PT test circuit.

1. What is the purpose of the 10K to +9v.?
2. R1 should be a 47k, it looks like a 470R
3. R5, a 1k is missing.
4. Why is a 1k2 resistor connected from the transistor to 0v, with the collector out to the 555 trigger.?

You are making it impossible to help you,if do not follow my step by step advice.

E

 

hi T,
That circuit photo you have posted is not the same as I posted as a PT test circuit.

1. What is the purpose of the 10K to +9v.?
2. R1 should be a 47k, it looks like a 470R
3. R5, a 1k is missing.
4. Why is a 1k2 resistor connected from the transistor to 0v, with the collector out to the 555 trigger.?

You are making it impossible to help you,if do not follow my step by step advice.
E

But my senior made it happened. I just want to know why? but when i removed the phototransistor. The buzzer and relay start working. After that, when i reconnected back the phototransistor and it start to sense ir beam. The sound gone.

 

hi T,
That circuit photo you have posted is not the same as I posted as a PT test circuit.

1. What is the purpose of the 10K to +9v.?
2. R1 should be a 47k, it looks like a 470R
3. R5, a 1k is missing.
4. Why is a 1k2 resistor connected from the transistor to 0v, with the collector out to the 555 trigger.?

You are making it impossible to help you,if do not follow my step by step advice.

E

Seems it is connected in reverse active mode btw..

 

hi T,
That circuit photo you have posted is not the same as I posted as a PT test circuit.

1. What is the purpose of the 10K to +9v.?
2. R1 should be a 47k, it looks like a 470R
3. R5, a 1k is missing.
4. Why is a 1k2 resistor connected from the transistor to 0v, with the collector out to the 555 trigger.?

You are making it impossible to help you,if do not follow my step by step advice.

E

 

hi T,
That circuit photo you have posted is not the same as I posted as a PT test circuit.

1. What is the purpose of the 10K to +9v.?
2. R1 should be a 47k, it looks like a 470R
3. R5, a 1k is missing.
4. Why is a 1k2 resistor connected from the transistor to 0v, with the collector out to the 555 trigger.?

You are making it impossible to help you,if do not follow my step by step advice.

E

After 1 day of hard-worked finally found out why haha. The vcc is actually connected to collector. and the pin 2 is actually connected at the emitter. Because my senior connect the transistor in reverse active mode. So it made me confused.Thank you anyway haha. Next time i ask question might be when i'm studying degree certificate.