Lpg gas detector

[mohd ezwan]

My friend have problem with his final year project. The problem is gas sensor (MQ-9) cannot detect gas. What is the problem with this circuit. Can anyone tell me or solve this for me. Please.

 

[KMoffett]

What circuit? Post a schematic of their circuit...how they are trying to use the detector.

Ken

 

[mohd ezwan]

hi

The schematic diagram and how do they work have been sent. Can you check for me Ken.

 

[KMoffett]

What have done to verify operation? Does the 5-minute-disable timer work and time out? Have measured the voltage at the junction of the 1K resistor, 20K pot, and detector output when LP is applied?

Ken

 

[mohd ezwan]

we already connected the sensor but the output is zero. we try to connect the buzzer as a output of the sensor but nothing happen. can u tell me what we suppose to do with this that.

 

[KMoffett]

You can't hook a buzzer directly to the sensor.

You can check the sensor independently by assembling the simple test circuit shown on page 2 of the data sheet in your first post.

Did you build your alarm circuit exactly as shown in the schematic you attached earlier?

Ken