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EMX vs G120 Power Consumption


#1

I’ve just done some current draw tests on our EMX and G120 boards, with interesting results. The boards are basically identical, except for the modules. They have a 16x2 LCD with back-light, microSD card, Hi-Res A-D chip, voltage reference and a couple of LEDs.

Tests were done with LCD back-light at around 25%, LEDs off.

Running identical code and current SDK.

EMX (running) 170mA
EMX (hibernate) 28mA
G120 (running) 179mA
G120 (hibernate) NA (crashes)

Surprising, as I thought the G120 was going to be faster and use less power, while it actually seems marginally slower and consumes slightly more power.

We use a 4000mA lithium cell and a LDO linear regulator (switchers don’t work in our magnetic field), so assuming we can get approximately 50% capacity out of the cell, we should get around 11 hours runtime, or 70 in hibernate. Just have to get the G120 to hibernate now.


#2

That makes sense. Something like a Pi calculation would use on-chip/cache RAM, while my timing was for boot-up, which would of course be reading in from external memory, and so slower.
I wonder why the power consumption is up, though? I read a post from Gus predicting the G120 would draw 50-80mA.