ESP8266 Community Forum

- Sun Jun 28, 2015 12:56 am #21885 Hi HolgerW,

Can you please share circuit diagram of your board driving relay on ESP12. My ESP12 crashes with Fatal Exception when I switchon relay.

Thanks

- Thu Jul 02, 2015 4:25 pm #22296

I have tried every solution mentioned above, even RST to VCC, but the wire still picks up noise and the ESP resets. If I hook up my oscilloscope with a high impedance probe, i can see the spikes on the RST line. After pulling the RST pin from the header, which was connected to a switch on the main board, it got a little better so i decided to cut the wire near the chip and put a 100nF cap. to GND. Did you try touching the RST line with a screwdriver, i'm almost sure yours will reset too. This solution works fine for me because I flash the ESP on a test board.

What is the 100nF cap good for?! As you cut the line you cannot use the RST pin at all - so why the cap?

I have this very same problem and it is totally frustrating. I'm switching inductive loads (window blinds motor, 0.5A) and get much reboots, sometimes it takes my the esp-01 more than one minute to "recover/reboot".

What I tried without success:
1. Connecting GND to mains ground
2. Connecting RST to VCC by jumper wire
3. Connecting RST to VCC via 5kOhm resistor
3. Connecting RST to GND via 100nF capacitor and
4. Removing the RST pin
5. Cutting the RST trace near to the chip
6. Running the esp off of a battery pack
7. Running the esp off of different psu's

I also have a 220uF cap between VCC and GND (near the PSU - problem?) and GPIO0 as well as CH_PD are pulled up with 5kOhm resistors.

Nothing helped!

- Fri Jul 03, 2015 1:01 am #22318

What I tried without success:
1. Connecting GND to mains ground
2. Connecting RST to VCC by jumper wire
3. Connecting RST to VCC via 5kOhm resistor
3. Connecting RST to GND via 100nF capacitor and
4. Removing the RST pin
5. Cutting the RST trace near to the chip
6. Running the esp off of a battery pack
7. Running the esp off of different psu's

I also have a 220uF cap between VCC and GND (near the PSU - problem?) and GPIO0 as well as CH_PD are pulled up with 5kOhm resistors.

Nothing helped!

Sounds very frustrating. I have one application switching mains through a relay. It was unstable until I cut the RST line on the ESP-01 as per Sweetpants instructions but without the capacitor.
Have you tried relocating the ESP so that you get it physically distanced from the motor?

- Fri Jul 03, 2015 4:59 am #22333 Hey, I can now also add to the not working list: ferrite core around the leads to the esp module.

The problem with inductive loads is not when they run, but if they are powered off. My module always reboots when the relay switches off. To reduce EMI I put an snubber on the relais C and NO terminals so that the peak at the switchoff is reduced. I use a X2 capacitor .23uF in Series with a 56Ohm 3W resistor. This mitigates the problem with crackling/popping sounds in the stereo and relay contact burnoff/welding together. Moving the esp away did not help because it is coupled to the relais board by the wires - I guess.

Actually cutting the RST trace helped most so far, but the problem is: if the module crashes, it takes ages to reboot and as the rst is not there anymore I cannot reboot it via the arduino (heartbeat check). Also how can RST be pulled up when the trace is cut? Someone wrote there is an internal pullup - is this really the case?! What pins have internal pullups on the esp01? Can the pullup be controlled by the software?