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matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10572

Posted: 09:32am 26 Jan 2019

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Now I've got a standalone PCB for the Armmite L4 I've been experimenting with low power battery operation.

This has revealed a numbers of interesting things:

In IR receiver takes 700uA when installed on the PCB

You can't measure supply power with anything else external and separately powered connected: Power usage went down from 290uA to 250uA when the USB/UART was connected, presumably through parasitic supply through the Console pins

Oled current is completely dependent on the number of pixels lit (obvious really) but the display pictured on an OLED would draw 10mA (30x greater)

Supply to the Winbond W25Q128 is negligible but I have included putting the chip to sleep when CPU SLEEP is operative

The battery charger/protection circuit causes no discernible current draw.

Choice of linear regulator is critical otherwise the quiescent current will be way above the current draw of the circuit (LT1117 = 10mA)

Given all of the above, my simple test environment pictured above should run for between 6 and 12 months on a single 3000mAh 18650 Lipo

New version 5.04.06
2019-01-26_200454_ArmmiteL4.zip

Changes:
SSD1331 display supported: OPTION LCDPANEL SSD1331, orientation, DCpin, RESETpin, CSpin
General tidy up and bug fixes
W25Qnn chip put to sleep with CPU
CPU SLEEP nn command can now take fractions of a second as in the example

Option explicit
Option default none
Dim float a,c
Dim string b$
CPU 24
TEMPR START 25
CLS
Do
Timer=0
b$=Time$
a=TEMPR(25)
TEMPR START 25
Text MM.HRes\2,8,Str$(a,3,1),cm
Text MM.HRes\2,22,Time$,cm
Text MM.HRes\2,36,Date$,cm
c=(998-Timer)/1000
CPU sleep c
Do While b$=Time$
Loop
Loop

Edited by matherp 2019-01-27

viscomjim
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Joined: 08/01/2014
Location: United States
Posts: 925

Posted: 05:30pm 27 Jan 2019

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This is perfect for a solar project I'm working on and this will keep my power concerns to a minimum. I found a cool little MPPT solar charge module here that should be perfect for an 18650 and a small solar panel. Thanks to matherp for this tremendous effort!

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10572

Posted: 06:58pm 27 Jan 2019

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Quote This is perfect for a solar project I'm working on and this will keep my power concerns to a minimum.

Glad it will be useful

Performance improvement in version attached

2019-01-28_045642_ArmmiteL4.zip

Now equivalent/faster than MM2 at 48MHz when running at 80MHz

paceman
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Joined: 07/10/2011
Location: Australia
Posts: 1329

Posted: 12:52pm 28 Jan 2019

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To complement a low power project and thinking of using one of cheap MT3608 boost converters in it, this YouTube link is very interesting. A simple hack drops the boost modules no load quiescent current from the usual 1mA down to around 60uA.

Greg

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