Dear experts
I have designed a Bluetooth+IR based home automation system with Atmega328p,ULN2003 relay driver and some 5v relays.The unit is being fed by a small 5v/1A SMPS from Hi-link.Normally the unit is running fine.But sometimes,when turning on/off inductive load(In this case,my AC ceiling fan),the micro is getting hanged.The power output from the smps(5v line) is filtered & decoupled with 470uF + 0.1uF cap.Also the clock lines of the Atmega is decoupled as per the datasheet with 27pf caps.I also tried adding snubber (with a 39R+0.1uF in series)at the relay terminals but that didn't change anything.So i thought to use a bidirectional TVS diode at the 5v power line.What should be the value of the TVS diode??Also,part no is much appreciated..Please help!!
I have designed a Bluetooth+IR based home automation system with Atmega328p,ULN2003 relay driver and some 5v relays.The unit is being fed by a small 5v/1A SMPS from Hi-link.Normally the unit is running fine.But sometimes,when turning on/off inductive load(In this case,my AC ceiling fan),the micro is getting hanged.The power output from the smps(5v line) is filtered & decoupled with 470uF + 0.1uF cap.Also the clock lines of the Atmega is decoupled as per the datasheet with 27pf caps.I also tried adding snubber (with a 39R+0.1uF in series)at the relay terminals but that didn't change anything.So i thought to use a bidirectional TVS diode at the 5v power line.What should be the value of the TVS diode??Also,part no is much appreciated..Please help!!