Voltage drop

As an efficient way of powering both the Pi + 4 x CAMJAM (6v) motors we are experimenting bespoke power board.  This operates in a similar manner to the ASTRO Piz-Moto HAT, we’ve tried last week.  The board fits neatly under the chassis – attached to an H-bridge/

 

The H-Bridge / 5v regulator module is constructed on a Vero board using a dual L9110S H-Bridge module and a standard 7805 5 volt regulator IC. The H-Bridge is rated at 800mA continuous with input voltage from 2.5 to 12V. The regulator input is supplied from 7.4v LiPo battery via a terminal block at the bottom and provides an output of 5 volts at up to 1A via a second terminal block at the top. The 5 volts is used to power the Raspberry Pi via pins 2 & 6.

Motor power to the H-Bridge is provided by a direct connection to the raw battery input at 7.4 volts.

As yet we’re not sure whether we’re using Li Ion batteries (hacked from PoundLand) or the LiPo alternative. Both work well in recent tests – but there is an obvious cost implication in needing to get a balanced charger for the Li Po batteries.

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