relay chatters when using beam sensors

Thread Starter

DWFerri

Joined Dec 17, 2010
4
The project i have been working needs help. What i have is a proximity switch controlling a set of infrared beam sensors,12 volt relay, and an actuator.

The proximity switch is to shut off the power to the whole system when it does not detect metal. The infrared beam sensors controls the coil of the relay. The relay supposed to turn on the actuator. Now the problem i having is the 12v relay chatters when the beam is broken but the relay does not come in to activate the actuator. Did put a diode across the coil of the relay and also across the actuator leads. Any suggestion to correct the problem. Thanks
 

BMorse

Joined Sep 26, 2009
2,675
From my experience, when a relay chatters, it either is being over powered or under powered..... what are the sensor outputs rated for that actuate the relays? Can you post specs of relay and sensors??
 

NM2008

Joined Feb 9, 2008
135
Have you set up the sensors in accordance to that of the "mini beam" link you gave.
Taking into account mounting, vibration, background, gain...etc

NM
 

colinb

Joined Jun 15, 2011
351
Maybe it's a form of 'bounce' caused by the sensor output. What if you put a low-pass filter on the sensor output to eliminate rapid bounces?
 

GetDeviceInfo

Joined Jun 7, 2009
1,729
altering my post here;

you need a diode across the relay coil. you need to know that the supply has enough to drive the circuit. you need to know that the prox will pass sufficient current to drive the circuit. why are you powering down the circuit with the prox?
 

strantor

Joined Oct 3, 2010
5,291
altering my post here;

you need a diode across the relay coil. you need to know that the supply has enough to drive the circuit. you need to know that the prox will pass sufficient current to drive the circuit. why are you powering down the circuit with the prox?
It's for a varmint trap he's working on. when the trap door is up (unsprung) the circuit is live. if the gate falls, then there will not be any more reason for the circuit to be active.

Don't ask him any sensible questions like "do you really want the trap door to fall on the varmint's back?"
PS I already told him to put a diode across the relay (and the actuator)
Did you try that yet?
 

strantor

Joined Oct 3, 2010
5,291
For potentially confused onlookers...I have DWferri's project here in front of me.

DWFerri:
I disconnected you solenoid and the relay no longer chatters. I think that the relay draws so many amps that it starves the relay, which causes it to open again; once the relay opens, the actuator is out of the circuit, so the relay has enough power to close again, until the actuator comes back into the circuit, and so on... hence the chatter. You need a beefy suuply (car battery) and probably a capacitor.
 

strantor

Joined Oct 3, 2010
5,291
Hey I stole the 220uF capacitor out of your trail camera (hope you don't mind) and put it in there; didn't work, but it did slow down the chatter. the problem is that your prox has 12V going into it and only 4V coming out. When I disconnect it from the circuit, it puts out 12V. I think it wasn't designed for much much output. No markings on it, so I can't look it up. Where did you get it? Might need to use it's output to drive a transistor to drive the rest of the circuit.
 

Thread Starter

DWFerri

Joined Dec 17, 2010
4
Thanks for the help everyone. I disconnected the prox switch and the relay stop chattering. The system functioned like it was suppose but with out the prox. Plan on replacing the prox switch with a limit switch.
 
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