# Overview

Here are links to the different board designs together with a short summary.



## HAN_ESP_Simple (Was: Board 1)

The project's original [board design](HAN_ESP_Simple). It

* is based on the ESP8266 chip.
* is powered by USB.
* uses a very simple voltage divider to demodulate the M-bus signal.
* has shematic and pcb design only available as finished pdf/png files.

### Status

Prototypes have been made and some people have started using them(?).

## HAN_TTL_TSS721 (Was: Board 2)

This [board design](HAN_TTL_TSS721) is a newer alternative to the original. It

* is an Arduino shield.
* uses the industry standard TSS721 chip to interface the M-bus.
* is optically isolated.
* has shematic and pcb design available in editable [KiCad](http://www.kicad-pcb.org/) source files.

### Status

Unfinished, just started.

## MBUS_Simulator (Was: Board 3)

This [board](MBUS_Simulator) is a M-bus master simulator to be able to develop and
test the other boards without being dependent on having and using a real
AMS unit.

### Status

Implementation done.


Please also see [Getting started building or modifying](GETTING_STARTED.md)