The first major hurdle to get over when linking the iPhone to a MegaSquirt ECU is the means of connection. The MegaSquirt has an RS232 serial port it uses for all communication but the iPhone doesn’t have a serial port available. To provide a bridge from the iPhone to the MegaSquirt there were two obvious solutions, the first being a BlueTooth to serial adaptor, the second being a WiFi to serial adaptor.
When this project was first launched Bluetooth wasn’t an option for the iPhone without going through an expensive certification program. Apple, with iOS 6, introduced support for Bluetooth LE, allowing apps to connect to supported modules.
We now have a choice of two routes to connect, WiFi or Bluetooth. WiFi is significantly faster in tests, especially at higher baud rates (MS2 and later) although there’s little difference at MS1 and MS1/Extra speeds.
This is normally seen in the number of log entries per second. In the most extreme case, running against MS2/Extra, the WiFi adapter delivers around 45 per second whereas the Bluetooth adapter only delivers around 6 per second. The data rate is displayed at the top of the realtime data view for reference. For MS1/Extra both Bluetooth and WiFi deliver around 12 lines per second.
Bluetooth is quicker to establish a connection as you don’t need to keep switching your WiFi over and can be found automatically without manual intervention after the initial connection has been made and the name of the adapter saved.
WiFi also has the potential advantage that it can be used with TunerStudio too. I have had some minor compatibility issues but, using the WiFi adapter I have connected with TunerStudio on my Mac.
If you have a “legacy” Roving Networks WiFi module, details of it’s use and setup can be found here.