I now have a functioning WiFi to serial adaptor built from three components that are freely available as ready made modules. All that is required are a few wires to connect them together and to load the software onto the WiFi module using a USB cable and the Arduino IDE. I’ll be putting together a complete description and a list of the components once I put the Arduino sketch on github.

The adaptor uses a NodeMCU WiFi development kit to supply the WiFi access point and to run the sketch that provides the connectivity. This is then connected to the MegaSquirt ECU via an UART to RS232 adaptor module. In order for the complete module to run from the 5V supply from the MegaSquirt serial port, it needs to use a 5v to 3.3v dropper module in the TX line from the RS232 module to the NodeMCU.

There are a number of advantages to using this unit over the RN and WiFly devices in addition to the obvious price advantage (a fraction of the price of those modules)…

• The module (via the firmware) provides a web interface to allow it to be configured for MS1 or MS2 (change baud rates).
• You can define the WiFi Access point name and also secure it with your own password.
• You can continue to use the internet via 3G while connected to the access point.
• The open source firmware will allow those who want to to add their own functionality to the link.
• Total cost for the complete module is around £12 GBP from Amazon