Before choosing any Bluetooth module for the MobiSquirt app you need to check a few things to make sure it’s compatible. Not all modules are compatible with iOS and not all those that are will talk to the app ! If you have a module that falls into that second category, let me know and I may be able to fix that.
There are two routes to go down for Bluetooth connectivity based on your budget and if you can wield a soldering iron. If you want to “build your own” from modules, this page is for you.
There are a number of “off the shelf” connectors available, some of which support BLE and iOS. The problem currently is identifying which is which. I may have a source for a suitable module in the UK and, if that comes to fruition, I will post the link here.
If you have a connector already, it MUST support BLE (Bluetooth 4.0). Without BLE your iOS device will not be able to communicate with the device. If in doubt, power up your connector and install the “LightBlue” app from the App Store. If your device is compatible you’ll be able to use that app to connect to it and see the services it offers. It’s possible that a screen shot of the device service information is all I require to modify the app to connect to your device. The example below shows the details from an HM-10.