This project is impressive, I really like it. Pity it is so silent about it. After all this work, are you not willing to finish it?

Hello,
This module is finally available to buy assembled. Now our project is complete, you can run the whole RS485 system after some shopping here, on openhardware.io. See details on the project pages.

Cheers,
feanor-anglin

@kimot in theory you might be right, but in practice... it just works. The propability of collisions is extremely low and this is, as far as I know, the only problem you can worry about. After all, it was not my idea to use MySensors with RS485:
https://www.mysensors.org/build/rs485

@tiana thank you for your interest. Reffering to your questions:

1. Technically 32 with SP485EE. Soon we will try to check out different transceiver, e.g. ST485ECDR. According to the datasheet, it allows 256 devices.
2. You mean by the manufacturer? No. To use FOTW updates you have to use Sensebender micro bootloader.
3. We are still working on this feature, we have no tutorial yet, but we plan to write one. For now, the only instruction how to do it is here:
   https://www.mysensors.org/about/fota

Hello rozpruwacz,
Thank you for your comment. This idea seems quite interesting for me and certainly I will look into it in the future. But for now you need to know the best way to power up this modules is by using one PSU for the whole bus. It is very important to have common GND on every module on the bus. To do this you will need 4 wires though.