Remote Control I/R TSOP4138 Help

Hi thank you for reading.

I have the circuit as below....All software is working fine.

However I am aware the IP Pin on my Processor (16F627A) is being spiked by mains EMI and causing issues. I know this and I can repeat it by jigging a light switch (Fridge and Oven Stat also do same). The circuit is battery powered by a 12v alarm battery then a LDO 5v Regulator. So no physical connection with mains.

The 5v supply has decouplers on in and out as per data sheet.... Also there is a 100nf cap in the socket of the 16f627A.


Any help in stopping my circuit getting spiked welcome.

See attached AndyCad sketch for circuit.

AndyAttachment 8806Attachment 8806

Andy, I would place a 10uF ceramic cap across the processor after the 100 Ohm resistor. I would also replace the 100 Ohm with a 10 Ohm. I have to ask what are you doing with the remaining pins on the processor? Also, what other circuits are you powering from the LDO? I am assuming the regulator is somewhere on the left of the schematic?

A Little bit more :-

The unused pins are set as outputs Using TRISA=00000000 and TRISB=00010000 (RB3 is the i/p for the InfraRed)

Only other cct is a clock DS1307 on RB1 and RB2 (SDA and SCL)

LDO is LM2931

Andy

Andy, What do you mean by " is being spiked by mains EMI and causing issues."? Please explain... What is it doing wrong?