Hey. I have more or less the following circuit controlling a relay: . I've deleted the values because I can't open it up to read the data precisely now, but the circuit works to some extent. The control is provided to me by the GPIO25 output on the ESP32 Vroom 30pin chip. The RM84-2012-35-1003...

Test on Tasmota. If you have resets it means a problem with the power supply. If none - a problem with your code.

>>21523731 .This is ESPHome, so in the code I did not create.

. One and two, you haven't shown the workmanship of the whole thing and what power supply you don't know if the AC is far from the cables and board. But the problem is with the power supply peaks on the esp.

First verify that the EN pin is properly polarised and protected against external interference.

. Add a circuit quencher to the relay contacts, then the ESP32 reboot problem disappears 95% of the time. . The latter. They are generated due to sparking of the relay contacts.

>>21523857 . I won't draw out the schematic now but I am posting a picture which may be enough for some: The power supply is a Chinese YINGJIAO with voltage regulation (as pictured). I should mention that there will eventually be two contactors in the box, with one 3f. So as you can see the environment is somewhat toxic. I'm considering a gasifier circuit, but on the other hand I'm thinking of taking the low voltage electronics outside because even the 5% unreliability mentioned by @khoam will annoy me greatly. On the other hand I'm thinking of replacing the ESP32 with something else without wifi with ethernet hooked up to the chip, something more resistant to the interference mentioned. After testing what I've built for myself, I have quite a bit of confusion.

This 5V relay has a coil with a large number of turns. There are interference-generating components nearby. This coil acts as a very effective antenna. As far as simple solutions are concerned, in addition to the gasifier circuit, you can try connecting the relay to 5V through a diode. Also observe if the problem occurs when the contacts are opened or shorted.

Or an optoisolator, it will get rid of interference from this side to gopio 100%.

. This will do nothing. The relay is fed from the same voltage as the ESP.

Yes. Supplying the 5V power supply from the same source on which the contactor was standing, generated the problem, as a surge to another supply reduced the effect by 90%. Nevertheless, there were still occasional reboots, so I was forced to take the ESP32 out of the box which has already eliminated the problems definitively. Thank you all for your comments and feedback. Regards

[Solved] ESP32 Vroom 30pin resets when controlling MC-25M20 relay via GPIO25

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#1 21523725 18 Apr 2025 23:30

nkznkz nkznkz

Level 9

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Post #1
21523725 18 Apr 2025 23:30

Hey.

I have more or less the following circuit controlling a relay:

.
I've deleted the values because I can't open it up to read the data precisely now, but the circuit works to some extent.

The control is provided to me by the GPIO25 output on the ESP32 Vroom 30pin chip.
The RM84-2012-35-1003 relay on the other hand controls the MC-25M/20 single phase contactor.

In contrast, I have a problem with the ESP32.
When switching the state on the GPIO25 pin, 4 times out of 5, the relay, and at the same time the contactor, switches on/off. On the other hand, this one time out of five, the ESP32 feels like it reboots, at which point it loses connection to WiFi.

.

When I have only the relay connected, the ESP32 works stably and does not lose WiFi connection. The trouble starts when I add the aforementioned contactor to the whole thing.

Should I focus more on the interference from the power supply side of the ESP32, or should I pay attention to the electromagnetic interference though?
Many thanks for any suggestions.
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#2 21523731 18 Apr 2025 23:35

xury xury

Automation specialist

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Post #2
21523731 18 Apr 2025 23:35

Test on Tasmota. If you have resets it means a problem with the power supply. If none - a problem with your code.
#3 21523756 19 Apr 2025 00:17

nkznkz nkznkz

Level 9

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Post #3
21523756 19 Apr 2025 00:17

>>21523731 .
This is ESPHome, so in the code I did not create.
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#4 21523857 19 Apr 2025 07:31

jarewa jarewa

Level 32

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Post #4
21523857 19 Apr 2025 07:31

nkznkz wrote:
Should I focus more on interference from the power supply side of the ESP32, or should I pay attention to electromagnetic interference though?
.

One and two, you haven't shown the workmanship of the whole thing and what power supply you don't know if the AC is far from the cables and board. But the problem is with the power supply "peaks" on the esp.
#5 21523885 19 Apr 2025 08:15

TvWidget TvWidget

Level 38

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Post #5
21523885 19 Apr 2025 08:15

First verify that the EN pin is properly polarised and protected against external interference.
#6 21524018 19 Apr 2025 10:26

khoam khoam

Level 42

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Post #6
21524018 19 Apr 2025 10:26

nkznkz wrote:
When switching the state on the GPIO25 pin, 4 times out of 5 the relay, and also the contactor, switches on/off. On the other hand, this one time out of five, the ESP32 feels like it reboots, at which point it loses connection to WiFi.
.
Add a circuit quencher to the relay contacts, then the ESP32 reboot problem disappears 95% of the time.

nkznkz wrote:
Should I focus more on the interference from the power supply side of the ESP32, or should I pay attention to the electromagnetic interference though?
.
The latter. They are generated due to sparking of the relay contacts.
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#7 21524938 20 Apr 2025 00:10

nkznkz nkznkz

Level 9

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Post #7
21524938 20 Apr 2025 00:10

>>21523857 .
I won't draw out the schematic now but I am posting a picture which may be enough for some:

The power supply is a Chinese YINGJIAO with voltage regulation (as pictured).
I should mention that there will eventually be two contactors in the box, with one 3f. So as you can see the environment is somewhat toxic.
I'm considering a gasifier circuit, but on the other hand I'm thinking of taking the low voltage electronics outside because even the 5% unreliability mentioned by @khoam will annoy me greatly.
On the other hand I'm thinking of replacing the ESP32 with something else without wifi with ethernet hooked up to the chip, something more resistant to the interference mentioned.
After testing what I've built for myself, I have quite a bit of confusion.
#8 21524989 20 Apr 2025 06:33

TvWidget TvWidget

Level 38

» | Helpful post? (0)

Post #8
21524989 20 Apr 2025 06:33

This 5V relay has a coil with a large number of turns. There are interference-generating components nearby. This coil acts as a very effective antenna. As far as simple solutions are concerned, in addition to the gasifier circuit, you can try connecting the relay to 5V through a diode. Also observe if the problem occurs when the contacts are opened or shorted.
#9 21525017 20 Apr 2025 08:04

jarewa jarewa

Level 32

» | Helpful post? (0)

Post #9
21525017 20 Apr 2025 08:04

TvWidget wrote:
When it comes to simple solutions, besides the gasifier circuit, you can try connecting a relay to 5V through a diode.

Or an optoisolator, it will get rid of interference from this side to gopio 100%.
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#10 21525032 20 Apr 2025 08:26

TvWidget TvWidget

Level 38

» | Helpful post? (+1)

Post #10
21525032 20 Apr 2025 08:26

jarewa wrote:
Or an opto-isolator, will get rid of interference from this side to gopio 100%.
.
This will do nothing. The relay is fed from the same voltage as the ESP.
#11 21527875 23 Apr 2025 09:34

nkznkz nkznkz

Level 9

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Post #11
21527875 23 Apr 2025 09:34

Yes.
Supplying the 5V power supply from the same source on which the contactor was standing, generated the problem, as a surge to another supply reduced the effect by 90%.
Nevertheless, there were still occasional reboots, so I was forced to take the ESP32 out of the box which has already eliminated the problems definitively.
Thank you all for your comments and feedback.
Regards
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Topic summary

An ESP32 Vroom 30pin module controlling an RM84-2012-35-1003 relay, which in turn operates an MC-25M/20 single-phase contactor, experiences frequent resets and WiFi disconnections when switching GPIO25. The issue does not occur when only the relay is connected, indicating interference related to the contactor. The problem is attributed to power supply disturbances and electromagnetic interference caused by relay contact sparking and the coil acting as an antenna. Suggested solutions include verifying power supply stability, ensuring proper EN pin protection, adding a snubber (quenching) circuit across relay contacts, using a diode in series with the relay coil, and employing optoisolation to eliminate interference on the GPIO line. The environment with multiple contactors and a Chinese YINGJIAO regulated power supply is electrically noisy. Relocating the ESP32 outside the interference-prone enclosure and powering the relay and contactor from separate supplies significantly reduced resets. Ultimately, removing the ESP32 from the box eliminated the reboot problem, confirming that interference and power supply spikes were the root causes.
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ESP32 Vroom 30pin resets when controlling MC-25M20 relay via GPIO25