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By MarkBresler
Hi, I am trying to create a battery powered system that will vibrate when certain acceleration limits are exceeded.

I have purchased the following SparkFun products: RedBoard Qwiic, 400 mAh lithium-ion battery, Adjustable LiPo charger, vibration motor, Haptic Motor Driver DRV2605L, Triple Axis Accelerometer Breakout MMA8452Q.

I intend to change the jumper on the RedBoard to set it for 3.3 V I/O. I am intending to use the JST connector on the charger board to connect the battery. I think it is possible to use the charger board solder connections to connect the battery ground to the RedBoard ground, and battery positive to +5 V. This should power the 3.3 V regulator and therefore the I2C bus. A disconnected plug in the barrel jack should prevent the USB jack from powering the RedBoard. While battery voltage will decline from about 4.2 to 3.0 as it discharges, I hope it will be enough to keep everything running.
1) Do you see any obstacles to this hack?
2) Do any of these chips have undervoltage lockout?

Thanks, Mark