Plenty of Brains but not enough Brawn....Is 12v Possible?

[list=][/list]Well, I couldn’t resist taking Sparki apart and refitting him with larger wheels and a bigger body so that he can serve wine at my wife’s parties… The new ten inch wheels increase his speed dramatically, and, since I increased his height by about 36", I added casters to keep him stable. Programming is simple, go from point A to point B and stop, then go back, so Sparki has plenty of brains to do this. Random wandering with ultrasound sensing is also something I’ve tried.

Unfortunately, the added weight of the new body has proven too much for Sparki’s 5 v stepper motors. They bog down frequently from too much friction and too much weight, and the wine often doesn’t make it to it’s destination.

So, my simple question is, is it theortetically possible to replace Sparki’s 5 v stepper motors and 4 AA batteries with the Adafruit 12 v stepper motors and a 12 v power supply without burning up Sparki’s board? I’m looking at adafruit.com/products/918. Looks like the connections, form factor and stepper configuration are identical, just a more powerful motor.

Thanks in advance for any help. If I make any progress, I will upload the video and the design details.

omg that sounds amazing! Unfortunately I have no technical help to offer but I would love to see it and invite you to guest blog at ashbotandsparki.wordpress.com/

Hi Dave,

The steppers motors you listed are the same power. Stepper motors rate their torque based on current pull, and the coils in those stepper motors have a higher impedance to match the current of the 5v motors at 12v.

More simply, higher voltage/higher resistance = same current = same power

You’d have to install some new geared motor type to make it more powerful. Sorry, Sparki wasn’t designed with a lift-kit in mind. :wink: (Although I’d love to see pictures of this monster!)

Thanks, I know nothing about motors or electronics, so I really appreciate the input. The motors do look identical, but I am confused because the 12 v version says it has almost twice the holding torque rating at 12 v than the 5.5 v version (25 Nmm vs 15 Nmm). However I assume hooking up a 12 volt power supply would probably blow Sparki’s circuit board so that probably isn’t a viable solution. And, even with twice the power, it might not be enough. SOOOO,

I was wondering if I could use the expansion port to add a stepper motor driver for a higher powered motor. I was thinking the Adafruit Stepper motor - NEMA-17 size - 200 steps/rev, 12V 350mA (adafruit.com/products/324) might work for my purposes. Any thought on that Idea?

Anyway, here’s a quick pic of my project. Also tried to upload a quick video, but I’m not sure if it went or not.


I think you’re getting a little beyond the scope of Sparki, but that’s exciting! I might have a solution for you, but its a bit hush-hush for now. Email me at joe@arcbotics.com