Wednesday, January 1, 2014

Personal Experience: Building the MintyBoost v3.0 USB mini-recharger

Happy holidays!

This Christmas, my brother-in-law gave me the best gift: a MintyBoost v3.0 construction kit and associated small electronics components. I set to work right after the holiday rush died down putting it together; my thoughts on the project follow.


In addition to the kit itself (and Altoids tin---Altoids included!), I received a new soldering iron and stand, small flat-Philips screwdriver, and desoldering braid. This would be a good starting kit for anyone interested in getting their hands dirty (for someone who has no tools, I'd also include a multimeter and tin snips; a table clamp would also never go amiss, and decrease the odds of singeing your table working on a project).

Unboxed. Android with Santa hat and napkins not included.


Altoids tin is not included with the project, but Nick provided me one. It came pre-filled! :)
The MintyBoost took me about three hours to fully assemble, from opening the box to testing charge. This was a fast project (especially compared to the interminable 3D Cube project).

Mid-assembly; almost all components soldered on.
I'd definitely recommend this project as a beginner's kit, though possibly not a first kit (depending on your user's level of comfort with soldering and small parts). Not only does it cover a decent set of skills (soldering to circuit board, identifying components, modifying a case), the instructions are really excellent and detailed, willing to throw at least a sentence of explanation into every component on the board. Would that all guides bothered with this level of detail! To be honest, I have almost nothing to add beyond what those will tell you in terms of component assembly.

Fully assembled and installed. There is plenty of room in there.
In terms of assembling the case: the Altoids gum tin that the project was originally designed for is no longer around, but it fits perfectly fine in the slightly larger Altoids mint tin form-factor. In fact, the larger form-factor means that there's room for a third battery in there if you're inclined to swap out the shipped 2-battery clip for a 3-battery clip. The documentation on batteries and the MintyBoost notes that 3 in series is probably fine, though 4 is inadvisable (your voltage will exceed 5 volts, which will be unhealthy for the MintyBoost's regulator electronics). I didn't mod in that direction, so your mileage may vary; by all means, drop a message to me or to Ladyada (via the "Feedback? Corrections?" link on the linked-to page) if you try it and find it works!

The USB port. I used copious amounts of hot glue here, for stability and edge protection.
I lack tin-snips, so I made due with already-damaged wire cutters to wreck up the side of the tin to make room for the USB port. I bent things out of shape a bit, but didn't leave too many sharp edges. The ones that remained: well, I'm a big fan of using hot glue in hobby electronics projects as the universal insulator and stabilizer, and that applied here also. Copiously applied; since this component will be taking the vast lion's share of physical stresses, I don't want it to budge at all (and I want those stresses impacting upon the tin, not the circuit board inside the tin). 
Snapped shut and ready for use.
The great thing about hot glue is that it dries soft and rubbery, so while the finished product that I made won't win any beauty contests, it guarded any remaining sharp edges against wayward fingers. But I could stand to own a rat-tail file for projects like this.


As the assembly instructions predicted, the device gets comfortably warm while charging. The battery guide goes into details on how the MintyBoost works, but long story short is that it stabilizes the voltage and lets the current flow freely, which can do a number on the batteries. The how to use guide also notes that it's best to think of this as an on-the-go booster, not a recharger; it's going to chew through batteries, and when the batteries are drained too far, some devices aren't smart enough to go to low-power mode, so an overnight charge could leave you worse off than when you started.

Charging up!

I gave it a shot with my Moto X, and am pleased to report that it can probably be added to the compatibility matrix. I was able to get it to click up 2% worth of charge in about 2 minutes.

Final Thoughts

This was a fun project. I'm going to have to hunt around on Adafruit and find more fun projects like this one!