Final Tests and Code
Listening to OthersI've made no secret that I took my inspiration from Lior's Alarmino project, and I was quite pleasantly surprised when he contacted me on one of my posts. He suggested that I take a look at the value of the filter cap I'm using on the 4V rail supplying the SIM900.
In his design, the bulk storage cap was charged by a linear regulator that delivered a maximum of 1A, but as my design uses a switch mode that's (nominally) rated to 3A I figured I could go smaller with my filter cap as my circuit can deliver a higher rate of charge - even with the substitution of the eBay sourced LM2596 circuit.
Thank You eBay!