Blink camera external battery

Doorbell with no batteries (inside)

This article covers most of information and pictures documenting my road to longer battery life and recharging facility of one of the popular camera doorbell.  

It consist of 4 parts:

1. Battery dummy with connecting points (provides non-invasive way of connecting wires into camera)

Here, I designed and 3D printed AA dummy with room for 2mm diameter 10mm long copper rivet as end terminals.

 
Fig. 1. Rivets 
    
                                                            Fig. 2. 3D model of AA battery

 
           
                                                                 Fig. 3. Model with rivets as terminals

 The way of soldering a wire to this is: remove rivet from its place in this assembly, solder from one side only, being careful not to "wrap" the solder around and trying to concentrate soldering spot to one side, to not colide with printed part. Tricky, but possible.

2. Battery charging and protecting unit

  The battery charging thing is a readily available circuitry named TP4056. Simple and sufficient here.



 It is default set to 1A charging current, just enough to charge doubled 18650. The default cutout voltage is around 2.5V. It may be changed by replacing one of the chips. I have tried it, but: the original one has auto-recovery mode, i.e. it brings the power back to the outputs of the whole module as soon as the battery voltage raise above 3.8V (unsure). The new, 3V-protected chip will cut off at 3V, and allow the voltage on the output of the module only after re-charging battery AND disconnecting it completely from the module (and connecting it back). So, with this one: never let discharge below 3V, or add some circuitry to disconnect the battery before using it again :(

3. Built-in pushbutton battery voltage tester 

Here, I designed simple circuit to do this one test. After pressign pushbutton the tester lights up some diodes which represent state of charge/discharge. The top diode lights when there is more than 4.1V, lowest dims when battery voltage drops below 3.1V 




4. 18650 battery pack 

All sits in my custom-made 3D printed box fixed indoor, on door frame opposite side of doorbell installation place (for minimal wire length and convenience).

 YT video link below:

English version: https://www.youtube.com/watch?v=cdTh-a3N8Zw

 Polish version: https://www.youtube.com/watch?v=64lrRmXyDsM

 

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