IR relay circuit malfunctions when touched

I have made this circuit once before and is working fine in my room and now when i have built a new one again using same circuit, it malfunctions when touched with bare hands. On touching the circuit, the relays start triggering automatically in random manner. Previously when this happened, a 10uF capacitor solves the problem when connected between atmega328p reset pin and ground. Please help. Circuit board’s pic is attached below.

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sorry for not providing circuit diagram for standalone atmega… its attached below. I have connected a 10uF capacitor between reset pin and ground and also a 10k ohm resistor from reset to +5V. I don’t know about AREF before… Is there I have to put a capacitor?

Anybody?

Rishabh8721:
I have made this circuit once before and is working fine in my room and now when i have built a new one again using same circuit, it malfunctions when touched with bare hands. On touching the circuit, the relays start triggering automatically in random manner. Previously when this happened, a 10uF capacitor solves the problem when connected between atmega328p reset pin and ground. Please help. Circuit board's pic is attached below.

If you are shocking it with static electricity, you are going to have to shield it somehow. I have found that high Kohm (200k ... 600K) resistance between frame ground and logic ground mutes this problem. Give the energy somewhere to dissipate.
Also you can adjust the environment (increase humidity). Where I live, High Desert Western USA, during the Winter outdoor humidity hovers at 75% at 20 degree F. But indoor 70 degree the humidity is 20 to 30%, I can generate a 1 1/2 inch spark, just draging my stocking feet across the carpet, somewhere around 15kV. At night in the dark, if I rustle the bed sheets I shock myself. Feels like ants biting!

Chuck.

Yes.. i agree, Here in india, its winter, and previously when i had made one, it was summer. But the problem is that now the circuit don't even recognise the IR signals. Is this problem possibly occur due to static charge problem? My other room's circuit is working fine. I have made two circuits and both have same problem i.e. not triggering relays from ir remote and the touch problem... Although switching relays from push button is working (i have also coded the relays to trigger with its respective pushbutton s).

Rishabh8721:
Yes.. i agree, Here in india, its winter, and previously when i had made one, it was summer. But the problem is that now the circuit don't even recognise the IR signals. Is this problem possibly occur due to static charge problem? My other room's circuit is working fine. I have made two circuits and both have same problem i.e. not triggering relays from ir remote and the touch problem... Although switching relays from push button is working (i have also coded the relays to trigger with its respective pushbutton s).

post a schematic.

when you say 'same' circuit, do you mean functionally the same or composed of exactly the same components?

You could be experiencing a 'corner' condition. The circuit is nonfunctional unless an out of spec component is used. Your first circuit maybe should not be working, but it is. and your copies are functioning to spec and not working?

based on your description, your IR receivers are blind? most IR remotes use fm transmission or fsk. both use a carrier frequency around 40khz (38-41) are you using Sharp IR modules or bare photo diodes/transistors?

Chuck.

On making the same circuit on breadboard I find out that I malfunctions when I touch the reset pin of atmega with hands. I have made a simple blink led circuit on breadboard and there also the led blinks abnormally when reset pin is touched. I had connected the 10k resistor from reset to +5V and also a 10uF(25V) capacitor between reset pin and ground. Although the circuit works perfectly when driven with battery i.e. when connected with laptop. What should I do?

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Rishabh8721:
On making the same circuit on breadboard I find out that I malfunctions when I touch the reset pin of atmega with hands.

Well don’t do that.

Seriously, have you noticed how most electronic devices are equipped with a cover? So the pins can’t be touched while in operation.

While I’m surprised that it was causing the level of bad behavior you observed, your body does act as an antenna. If you have an amplified speaker, unplug it from your audio source and touch the end of the cable - note the noise created when you touch it.

Unless your application requires the user to stroke the pins of your creation, I’d suggest just boxing it up…

Oh - and yeah, if you don’t have bypass caps, definitely fix that. Without them, anything can happen.

I have capacitors between pin 7-8(0.1uF), pin 21-22(0.1uF), power supply output(10uF) and one between reset pin and gnd. LED Blink schematic circuit attached below. Obviously I had covered my previous circuit pcb with tape and is working till now perfectly. But this time its behaving very annoyingly. Although I will cover the whole circuit with tape or put it in some box but is there any other solution to fix this because its working magically alright when power is supplied through battery. Please check out my circuit for any mistakes I have made.