The story
A gate that worked fine for years, and then did not.
For years our gate opened with a phone call. You dialled the number of the unit, it recognised your number, hung up and pulled the relay. The call never connected, so it never cost a cent. Simple, and free.
Until it stopped. And not just for us — all over the island, gate openers of every brand went dead at the same time. The cause turned out to be the mobile network: the old 2G network those units depended on was being switched off.
The obvious fix was a newer 4G unit. We bought one, and it half worked: text messages arrived, but calls no longer connected. The chip inside explained why — it does not support voice calls over 4G. What is left is opening by SMS. And every text message costs money.
We were not willing to settle for that. Instead of buying a unit that pushes the problem onto your phone bill, we built a module that simply uses the internet: WiFi at the gate, and where there is none a MiFi or 4G router in front of it. SMS is only an optional extra. That became TapIsla.