Todays topic is... power saving!!
Now, the GT and VT are in no way low power devices. They both use ESP modules for their wireless connectivity.. this is VERY overkill for what they need, but there are not many wireless ICs which allow such customisation and support BT,BLE and WIFI.
Anyways, I believe the GT uses around 125-150mA, this varies depending on when connected to a wireless connection. I don't expect people to leave this permanently plugged in, but, there will be some that do (Even though we would not recommend it).
For a car battery, the average amp hours of a car battery is around 40-65... this means our 0.15amp tool "Should" be able to be connected to the car for 266hours (11-12days) before draining it. I do feel that number is acceptable.. but... it can be much better.
SAE standards indicate a cas total current draw must be less that 50mA after 1 hour. Thats the TOTAL draw of everything in the car.. so... adding the GT to this means it would be around 200mA. Now, that reduces the total battery time to 200hours (8.3days), now its closer to around a week worth.
Our main power user is the ESP, turning this off drops the power usage to around 40mA ish, so thats around 2-3x less then with ESP on. This would then result in around 90-100mA draw in the car assuming worst case scenario of car current draw.
Realistically, the tool should go into a deep sleep, around 1-2mA. This could be achieved by forcing the tool into low power mode, and to wake up after 'X' seconds. The only main issue I see here is how should the tool know when to wake up. Maybe it could sleep for 5seconds... wakeup.. the search for a pin change state on the support protocols (ALDL,VPW,CAN) for say.. 200ms.. and if it sees nothing, it then goes back to sleep?
Im not sure if we have enough flash to even fit this.. but since its basically just going to a deep sleep.. then reading some pin registers... it 'shouldnt' be too tasking.
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