Hi,
I have recently built the radio controlled switch circuit shown in the link below Fig A.
It works fine on its own driving a relay operating an air horn, but when additional servos are added to the receiver things change.

I noticed that when initially powering on the transmitter the servos jump, this in turn causes the switch to latch for about 2 seconds causing the air horn to sound, this at times also happens when turning the transmitter off.

What I am wondering is, is there anything that can be altered within the circuit to prevent this.
I also added a 220uF cap across each servo motor. This steadied things but, made the problem intermittent.

Thanks for your time.
Regards NM

http://www.uoguelph.ca/%7Eantoon/gadgets/rc-sw.htm

 

Hello,

How did you connect the horn and servo's together?
Is there a resistor at the input of the 4013, like in the second schematic?
The input resistance of the 4013 is very high and sensetive to pulses from the powersupply.
Did you put a capacitor (of about 100 nF) between pins 7 and 14 of the 4013?

Greetings,
Bertus

 

It sounds to me like you have a transmitter problem, rather than a problem on the receiver end.

You might try switching your transmitter's antenna to a dummy load before powering it up or down.

BTW, instead of the IRFZ24, an IRLZ24 should've been specified. An IRFZ24 requires Vgs=10 to be fully turned on, where an IRLZ24 was designed to work at logic level voltages(Vgs=5)

 

Is the problem solved by always turning the transmitter on first and off last?

John