Pulsed relay driving

[NigelCG]

Hi, I'm new to EMS-ESP, but have used MQTT for a number of years.
Currently using NTP connected ESP8266 to trigger relay on tumble drier start button at 2 mins past midnight for 2 seconds. This makes use of electric car low tariff (midnight to 07:00).
Having installed EMS-ESP32 module, I would like to eliminate the tumble drier ESP module and use the EMS-ESP32 board with an external relay. I've looked at the schedule section and tried various things, but can't seem to find anything similar.
Any thoughts please.
Regards, Nigel

[proddy]

did you look at https://docs.emsesp.org/Configuring/#controlling-relays ?

If that doesn't work, let us know how your ESP8266 version works. Also, be very very careful with switching 220/240V

[NigelCG]

Thanks for that. I did look at that and have added a "TDRelay" (digital out) on pin 22 under analog sensors, but failed to see how to link it to a schedule and how to set up just a 2 second pulse.
Re your comment on mains, I installed a commercial DIN rail 12V relay inside the drier, so I only need to pulse it externally using an ESP-01 relay board for extra isolation. I'm a retired electronics design consultant, so also understand which end of a soldering iron gets hot :-)

[proddy]

ok! I think I understand now. I would create two Scheduler entries in EMS-ESP, both type "Schedule", one to start 00:02 with a command like analogsensor/<the name> and the value 1 for on, and another entry for 00:04 with the same command with a value of 0 for off. This assumes the relay works as a switch. There's a rough example in https://docs.emsesp.org/Configuring/#conditions

[MichaelDvP]

@NigelCG Is the 2 second momentum switch required, or does 1-2 minute (as proddy metioned) also work.

• You can set the io-port for a minute and add a monoflop with 2 transistors or a NE555.
• I thought of a PWM to generate the pulse, but PWM minimum frequency is 1 Hz, we can't use 0.01 Hz.
• Changing schedule to second resolution will imo lead to many users flooding and blocking the scheduler.
• We had a request before to add a delay for triggering the command (e.g. for trigger on change). This would also help here, but is a lot or work for only a few use cases. Maybe add a delay only for immediate trigger, then any schedule can call the delayed immediate command. But this is difficult to explain to most users.

Sorry, i don't have a simple solution.

[NigelCG]

Thanks Gents, I will have a look over the weekend and see if I can at least trigger the relay.
To be lazy, (and as a temporary trial a year ago!) I put a PP3 (9V) battery in the ESP01-relay box to save multiple wall warts, so a 2 second pulse at midnight gives a long battery life compared to 2 mins.
Cheers

[MichaelDvP]

Have you tried what happend if you press the button a minute. If it is just a start button without any short/long press options it will work.