QT PY with STEMMA power and LiPoly charger BFF

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jcurryhydro
 
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QT PY with STEMMA power and LiPoly charger BFF

Post by jcurryhydro »

Hi everyone,
I have an Arduino MKR NB 1500 connected to a QTPY SAMD21 using a STEMMA cable. The QTPY runs using the power from the Arduino. Is it safe to use the QTPY with BFF charger and a battery at the same time it's connected to the Arduino? Thanks,

Mike

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dastels
 
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Re: QT PY with STEMMA power and LiPoly charger BFF

Post by dastels »

Not likely. You'd have 2 power sources connected together which is never good.

More concerning is having the two boards connected via I2C/STEMMA. How are they wired?

Dave

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jcurryhydro
 
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Re: QT PY with STEMMA power and LiPoly charger BFF

Post by jcurryhydro »

Hi Dave, thanks, it sounds like I will need to find a different approach - When the Arduino is powered on, I want it to communicate with the QT PY and also be able to remove power to the Arduino for short periods while the QT PY stays on. I wired them using Adafruit item #4483 - QT to Arduino MKR 100mm cable.

Mike

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dastels
 
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Re: QT PY with STEMMA power and LiPoly charger BFF

Post by dastels »

You can have them communicate via I2C (one side will need to be in peripheral mode) but not powered. Just connect SDA, SCL, and ground.

Dave

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jcurryhydro
 
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Re: QT PY with STEMMA power and LiPoly charger BFF

Post by jcurryhydro »

I am using the same battery to power both the Arduino and the BFF charger. The QTPY controls the EN pin on an Adafruit powerboost 500 that powers the Arduino with a USB cable. The wiring from the battery will connect in parallel to both the powerboost 500 and the BFF (see image). Removing the power wire from the I2C cable is a good idea, thanks,

Mike
qtpy.png
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