“It works well for my use case (I am only sending SMS with it). The Raspberry Pi has the ability to turn the mobile chipset on and off. However, while there is an LED to say it is on to the user, it doesn't seem connected to the Pi such the Pi has no idea if the hat is on or not.”
“I bought this mainly for the HAT form factor and GPS as it has an external antenna connector...with the hope of playing around with the gsm/gprs at some point (which I haven't done yet). The gps works just fine but there are a couple of idiosyncrasies with the board. When power is applied, the board doesn't actually turn on. You have to either push the power button on it or luckily you can toggle gpio4 and that turns it on as well, so you can add it to a startup script. Also the gps module isn't powered by default so you have to send a serial command to turn it on, then any setup msgs you might want to send. Again, easily done with a script. A potentially bigger issue is that the PPS signal isn't routed to any of the gpio pins. So you have to solder a wire to the PPS led on the board if you want that signal. Not a big deal if you are used to soldering, but potentially off-putting if you aren't. But then most folks that buy this board probably aren't all that interested in the timing functionality given all its other features. In the end, it does what I bought it to do and I'm happy with it :) Hopefully I'll get around to trying out the gprs!”
