Send serial commands via Homey

I own a receiver that only listens to commands via a serial interface (RS232). There’s no IP connection or app to control this device and also infrared is not ideal due to location of Homey. It’s only 4 commands that I need for now and feedback from the receiver to homey is not required.

What options do you see to let Homey control this device? I believe there are some apps that use serial commands over IP (P1 smart meter?).

These are the options that I see:

  • Purchase serial to IP converter (like this one). Still Homey needs to be able to send the commands to an IP.
  • Get started with arduino and homeyduino. I don’t have any experience with arduino, so this might be too challenging.
  • Homeyscript?

I think it’s going to be difficult without writing a Homey or an Arduino app (I initially thought that a combination of a serial-to-IP converter and HomeyScript could work, but it turns out that it’s not possible to create generic TCP/IP connections from HomeyScript).

If I understand correctly, the receiver can be controlled through IR as well. If so, you could look at the Broadlink RM devices. I have no experience with them whatsoever, but the Homey app states that they are WiFi-to-IR devices.

Ik ben ook opzoek naar het zelfde alleen dan voor mijn beamer. Ik doe het nu met een WiFi IR controller alleen ik vind dat nog niet mooi werken.

Ik blijf dus echt opzoek naar een manier om via RS232 te werken. Ik ga nu proberen het te doen via een paspberry pi en daar Domoticz op te installeren.
Ik kan wel een commando sturen naar de beamer doormidden van pyserial alleen ik kan geen script starten.
Het heeft eerder gewerkt alleen toen is mijn pi gechrasht en moet ik weer opnieuw beginnen.
Ik moet er nog verder in duiken maar dit is opzich wel een stabiele en goeie oplossing.

NL: Waarom geen ESP32 of ESP8266?

Eng: Why not using an ESP32 or ESP8266?

If you could please keep the conversation in English as much as possible, then more people will be able to participate and help you. If you would rather not or can’t communicate in English then please check out Non-English boards/catregories:

Maar dat is een WiFi module voor de arduino? Wat moet ik daarmee?
Ik begrijp je niet.

Sorry, we have to talk English here.
Homey can communicate with ESP devices (HomeyDuino or webhooks), see:

in the ESP you can translate messages to a serial output.

Best solution would be a IP to serial box.

Building your own with an ESP32/8266 is possible but requires a logic level shifter some other components, time and coding skills.

There is a a good working SSH App available for homey so if the IP/serial box supports SSH then you’re golden. If it only does telnet then you’ll need to either use homey script or build a simple App. Telnet is the most straight forward protocol possible so that shouldn’t be to difficult to get working.


I have a couple of these laying here around. Still had no time to properly test them. I Wanted to make a couple of wifi to serial adapters for work.

I’m not sure that these boards use 5v on the rs232 side while using 3.3v on the ttl side. (Esp logic levels are 3.3v) there’s no voltage regulator on the board.

A logic level shifter is still required. Not that that’s an issue.

RS232 used weird voltages if I remember correctly (something like ±15V).

By the way, ESP’s are 5V tolerant on the I/O side (but not on the power side), at least that’s what the Espressif CEO publicly stated a few years ago.

Just digged a bit deeper and your statement is correct although there appears do be a wide subset of different voltage levels. Where i got the 5V idea from is a mystery. I double checked the PCB’s i have here and the shared image from @JPe4619 . It includes a Maxim MAX-323 IC that handles this internally. So it should be a one stop shop.

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I made a arduino controller with a NodeMcu Lolin esp8266 v3 and a rs 232 board to control my amplifier by using the homeyduino library and mqtt. I used this controller. I can now control my amp by homey.

Maybe the eport E20 is something to use. I already see applications with the DSMR P1 port of the Dutch electricity meters.