Updates

2023-09-26

I ordered a new batch of brand new boards (revision 0.0.7). I optimized the board to be more production friendly and added more parts as default, since most of my users want the full featured module with all available connectors and options. This means, there are less options now, because everything is already included. ETA is end of October, just when your buderus starts working ;-)

2023-07-20

I'm out of stock now. Since the orders declined during the last weeks and I do not expect many orders within the next weeks, I'll not order a new batch during summer vacation time. If the waitlist (not the wishlist) has a high number (>50) after summer vacation time, I'll order a new batch. It makes no sense to order smaller batches than 100 since the initial cost is quite high.

2023-03-28

A video about the assembly and flashing is now available on my YouTube channel. (Version 0.0.7 is mostly finished...)

2023-03-17

The new version 0.0.6 modules finally arrived! I started already with testing and when everything works like planned, I'll open the shop again tomorrow.

Important Notice

• If you are searching for the bare PCB, I created a seperate product page for that
• Please be aware, that the firmware is currently still under development...
• Please also read my blog post on this product (see Dokumentation link below)

What is it?

It is a slot card for some Buderus Logamatic (e.g. 2107-type) that connects the serial interface and attaches it to the serial interface of an ESP32-WROOM-32D/U module to be linked into a WiFi network. You can also write your own firmware to make it Bluetooth connected.

Why did you make it?

Because I need to attach my heating system to my Smart Home since the burner raises an error quite often. I'm then forced to commit the error, wait half an hour for the water to heat up or take a shower with cold water.

Now I can connect it to my Home Assistant using ESPhome and send me some pushover message, as soon as the error occurs.

What makes it special?

The original Buderus KM271 module (with a RS232 level shifter) is not produced anymore and costs around $100. And it still needs some additional hardware to lift it to your WiFi network.

Recently I found out, that Buderus is also selling the KM200 (in version 2) for "as low as" 270 bucks. I did not see it in action yet, but I believe it locks you in to the Buderus cloud and you have no chance to get the data into your smart home...

What does the package (not) contain?

If you order the option with ESPhome, you just need to

• plug it into your logamatic (switch it off for mounting)
• wait a minute for the fallback WiFi to show up
• do what you want (e.g. OTA-upload another firmware)

Alternative firmware based on PlatformIO/Arduino from Sven. Read the docs to see, what great things you can do with it. It also provides a full blown WebUI for all people that don't have a smart home system...

Jens and Bascht added many sensors to the latest ESPhome variant. Most of the commands are already implemented. Mostly the scheduling is not supported, but this is not really needed, if your smart home takes over full control :-)

You do not need the EEPROM if you do not write your own firmware for this module (at least for the moment there is no support planned)

Options

I ordered assembled boards that all contain:

• ESP32-WROOM-32D-N4 (4 MB Flash version, the 8 MB version had crazy lead times)
• NO EEPROM
• NO Exhaust Sensor circuit
• NOT soldered THT parts
• NOT beveled edge connector

If you choose the assembly option, I'll solder the THT parts and the chosen options for you.

For tinkering in depth, I recently wrote some hardware description.

Thanks

The 0.0.1 prototype PCBs have been sponsored by PCBway. I totally can recommend this manufacturer for your own PCBs. A reader of my blog sponsored also 10 PCBs of the 0.0.5 version and added the exhaust temperature circuit.