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IRNAS / pulseox-hardware

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V2 - battery #5

Open VojislavM opened 7 years ago

VojislavM commented 7 years ago

LiPo battery for powering device.

The battery capacity will be determent later on. This is a low power device so the battery peak current should not be a problem.

VojislavM commented 7 years ago

Battery needs to be rethink because it seems that the current device is powered of a standard AA battery.

VojislavM commented 7 years ago

Because this is a portable electronic device better choice is LiPo. 4.20v = 100% 4.03v = 76% 3.86v = 52% 3.83v = 42% 3.79v = 30% 3.70v = 11% 3.6?v = 0%

LukaBanovic commented 6 years ago

@kostko here is everything you need for charging control.

VojislavM commented 6 years ago

PIN PA1

image

kostko commented 6 years ago

So this has changed from the previous PCB? Because previously A1 was used for power management of the detector (to turn it on/off). So looking at the new PCBs, the detector is now always powered?

kostko commented 6 years ago

Ok, @VojislavM confirmed that this is the case. Previously this was meant for reducing power usage by turning the detector off when it was not needed (but this was never actually used in the firmware).

We should benchmark battery performance to see if we will need to do any power optimizations.

kostko commented 6 years ago

Battery voltage monitoring is now working with my development firmware. We need to find a good way to display this information on the (limited) screen. Any suggestions?

LukaBanovic commented 6 years ago

I suggest keep the size of the "HR" and the bpm number as it is but move both down so that the SpO2 and HR numbers are aligned at the bottom, then there is some space free in the top right corner. You can add in the time and constantly display the calculated "remaining" time of the battery in xH yzM.

VojislavM commented 6 years ago

https://learn.sparkfun.com/tutorials/battery-technologies/lithium-polymer

LukaBanovic commented 6 years ago

I've measured the battery, when full, the voltage is 4.21V. Present BAT LO sign when the voltage drops below 3.5V.

LukaBanovic commented 6 years ago

I suggest using screw terminal for battery pins instead of headers as a universal solution for battery mounting. Currently the pin holes on some LiPo batteries connectors are too small to fit onto header pins.