Preparing the serial module

RS232 to TTL (UART) module male DB9
Additional (red) wire added to provide power for the modules.

If you want to power the connection from your MegaSquirt ECU, you will need to make a slight addition to the module you have bought.

The ECUs supply a 5 volt output on pin 1 of the DB9 connector and that pin needs to be connected to the VCC terminal of the serial adaptor’s PCB.



On the module I have used, most of them will be similar, that’s easily achieved by soldering a wire between the DB9 connector and the PCB. You can see the red wire I have added in the picture. The pin numbers are moulded into the plug with pin 1 being the furthest right of the row of 5 pins as you look at the connector from the back. If your connector uses a pcb mount with 90 degree pins to the PCB you may have to follow the pins or use a meter to check you have the right one.

Once you have the DB9 RS232 module prepared, move onto the Bluetooth module…

WiFi Module builders, go here…