Logitech M555B charging dock

 

 

Part 2

Circuit

Quick simulation to see if theory for the charge indication works
Im looking for a voltage drop across a diode, high enough to allow for a small current to be run through base of a PNP
If it works it could source a diode as sonn as conection with battery is made.

LM317 set at 60mA as constant current charger, one can leave it charging
indefinetly since it uses NiMH cells.

Pspice simulation collaborates my thery, voltage levels seems to be ok

 

Components in mockup

Voltage drop over diode 1N4001 connected to base-emitter on BC549 lights the LED when docking mouse completes the circuit.

Proof of concept for the voltage drop sensing BC549

PCB layout

PCB for the chraging circuit

 

PCB build

PCB completed, the circuit fits snuggly inside a 3D printed charging stand

 

Charging stand on next page