NE555 reset pin using transistor

[Alec_t]

sensor is high

In that case Bertus' suggestion (post #18) should work.

 

[tomcer34]

Hello,

I would try this on the rest pin of the 555:
Bertus

No, I tried it now and ne555 output stays low and sensor stays high

 

[bertus]

Hello,

How do you trigger the sensor?
Is the magnet strong and close enough?

Do you see the led change when the magnet is close to the sensor in my schematic?

Bertus

 

[Alec_t]

I tried it now and ne555 output stays low and sensor stays high

That's what should happen, until the sensor is triggered. Sounds like the source of your problem is elsewhere.

 

[tomcer34]

Alright, I just found out that when sensor is connected on pin 4 and to gnd through 1k rezistor it's triggering some safety feature on it. So I will try different one. Or has someone any idea how to bypass it?

 

[tomcer34]

Hello,

How do you trigger the sensor?
Is the magnet strong and close enough?
Do you see the led change when the magnet is close to the sensor in my schematic?

Bertus

I'm using diomidium magnet or how it's called in english. Yeah it's strong. Problem is some safety feature on sensor. I don't see led turning on, when measuring with multimeter, sensor is just off, until I turn of and on circuit. I had this exact issue with my first design. I thought it had to do with flyback current, but I guess I was wrong. I will try linear sensor, but I didn't want to use, because its linear and in my application, there is more then one source of magnet pole I can say?

 

[tomcer34]

That's what should happen, until the sensor is triggered. Sounds like the source of your problem is elsewhere.

Yeah, it's the sensor, I will try different one. It's SS40A.

 

[bertus]

Hello,

Looking at the datasheet, the sensor latches until reverse magnetic field is given.

Bertus

 

[tomcer34]

Hello,

Looking at the datasheet, the sensor latches until reverse magnetic field is given.

Bertus

I tried it after my problem started acquiring, but thanks for the tip. I will have to buy appropriate sensor for that I guess.

 

[NMNeil]

View attachment 53495
This it is. Sorry for my transformator, but I didnt had library for that. I cannot upload file with my schematic. It was made in Eagle

What's the circuit to be used for?