M30 Capacitive Proximity Sensor

[sich]

Hi, have you tried to test the black wire output manually using multimeter? Also no signal change (HIGH <-> LOW)?

[kenshih]

Please try to detach 660 ohm from your circuit, connect 12V source directly to the sensor. Hope this will help.

the reason why i add the 660 ohm resistor is because the datasheet for the capacitive sensor state that the operating voltage is 12~24V and the current consumption is less than 22mA. if i connect 12V from the power supply directly to the sensor, wouldn't it produce infinite current and fry the sensor? <= learned the lesson after frying a LED...
by connecting it with the 660 ohm, it will only sends in around 19mA of current which is within the accepted range of the capacitor...

no offence, just clearing my doubts

[kenshih]

Woh.... capacitive sensor? Great, what is the application?

the application for the sensor is stated in the datasheet... u can refer to it in from the link i posted in my first post... =)

[kenshih]

Good to see you know how to modify the sample circuit from rotary encoder, at least it is useful .

The code seem to be correct. Maybe the resistor highlighted by hyng should help.

jus giving credit to the original circuit as i don own it... =)
save me alot of work as i did that circuit within minute with paint... lol

[kenshih]

Hi, have you tried to test the black wire output manually using multimeter? Also no signal change (HIGH <-> LOW)?

not actually. aren't it gonna fry the fuse in the multimeter if i measure resistance with a life circuit??

[ober]

the reason why i add the 660 ohm resistor is because the datasheet for the capacitive sensor state that the operating voltage is 12~24V and the current consumption is less than 22mA. if i connect 12V from the power supply directly to the sensor, wouldn't it produce infinite current and fry the sensor? <= learned the lesson after frying a LED...
by connecting it with the 660 ohm, it will only sends in around 19mA of current which is within the accepted range of the capacitor...

Basically, current depends on load, not source. Not to go into complex part.

LED can burn because it has forward voltage, ranging from 1.5V to 4V depends on what LED. In other words, voltage across LED should be 1.5V to 4V to make it forward bias. But once it is forward bias, resistance in LED drop rapidly thus drawing more current over it, further burn it. Therefore we need current limiting resistor for LED if the source cannot limit current.

So don worry about the sensor because it is not LED.

[kenshih]

i've detach the 660 ohm resistor from the sensor and it starts working.(turn out that the LED on the back of the sensor is the indication of "object detected")
there is just one last problem, there is still no response from the LED in my circuit. i've tested the LED and its working, and i've tried connecting ground instead of the black wire(output) from the sensor to the same point, and it works(the LED turned on)... need help here... >.<
nevertheless, thx for guiding me through this... =)

[ober]

Photo of real hardware should be helpful

[kenshih]

this is the photo of the circuit i constructed, currently having nothing on it as it is meant for testing the sensor as well as obtaining the sensing range of the sensor. it is similar to the pic i post earlier.

[robosang]

Em....

I think I will suggest to connect the pull up for sensor and power the sensor only, test the sensor alone.