For some time now, I have wanted to do some field medical equipment. Among others would eventually be an IV station, a portable X-Ray or mini MRI machine, and included in this was a centrifuge for separating out blood and other fluids. But it would also have uses in geology and other Adventure Team missions.

GOAL

My plan was to create a piece of equipment that definitely looked medical. I did a lot of web searching for medical centrifuges, and a surprising number were white and blue, and I had just gotten these lovely turquoise and teal filaments, and as the Huxter Labs logo is blue (though I lean towards turquoise sometimes) I thought I could make something quite lovely.

I wanted to spin these glass bottles I got for the Save the Endangered Rhino set I created in 2014, and recently revived as a whole new set with Cotswold Collectibles. I wanted the vials to fit into these buckets that would be hinged at the top to spin outward.

A centrifuge works by spinning very fast and causing centrifugal force to act as extra gravity that causes denser particles in a liquid to work their way to the outer part of the circle, while less dense particles are pushed towards the center. Just like gravity, but faster.

So I put the buckets on little hinges (clipped pieces of a paper clip) and they dutifully spun, and when the motor is turned off, they slowly spin and angle back down to rest.

 

POWER

Recently, Dollar Tree stocked some battery-operated mini-fans. These fans had a battery compartment for 2 AA batteries, a switch, and a quiet fast motor. For $1.25 per.

I bought a couple and started measuring out and planning. My first goal was to get the motor to fit into a chassis that would look fairly cool, be similar in theme to my previous Huxter Labs RACCS equipment, and still have room for the switch and battery leads, without having to rewire anything. I don’t like soldering, and if all of it is in place without alteration, that’s a huge win.

The first attempt used two AA batteries, but the bulk of the battery compartment I had to make (from scratch, to fit the metal spring, bump, and rear connector so two AAs can work together) and it worked fine after a fair amount of effort. Then I figured two AAAs would be smaller which would allow me to reduce the bulky base a bit.

And the battery would spin the motor for a while, but soon run out. So I thought of moving to a 9V battery, which should make the motor spin faster.

And that worked too, but for this centrifuge to actually (I mean for real) work, the spinning would have to be done over a fairly lengthy time, and batteries wear out too fast.

 

EUREKA! USB!

I could throw out the bulky batteries entirely if I could buy some USB-C sockets and allow people to power this thing by a USB-C cable.

USB-C? Why? Because the world is moving to USB-C. It doesn’t benefit me much here, as I am using only to get the power output, but the idea of not having to figure out which way up to plug in is quite attractive.

So I found some USB-C sockets and bought a few to test. And they work!

Connect wires to GND and VBUS and you get a consistent 5v power, and when I touched the motor wires to these, the thing spun very satisfyingly.

So I set out to refit the body to take these little USB-C circuit-boards.

 

To RACCS Or Not To RACCS?

RACCS is the Ready-Attachable-Configurable-Component-System, a rack I created to fit on the back of a GI Joe Adventure Team All-Terrain Vehicle so Joe can configure his own adventures using various modules I created. (Search this page for RACCS and you will see a bunch of them. But there are even more I haven’t take time to write about yet.)

When I was creating a prototype for a new Weather Tracker or Environmental Analyzer, I found a way to make RACCS pegs fold up so new units can act either as standalone equipment, or slot into the RACCS slots. So by folding down these hinged pins, you can attach this Centrifuge to a RACCS-equipped ATV.

(Oh, I also created a new version of RACCS that has legs, so it can also act as a table. In fact I made a set of legs that are also compatible with previous RACCS by slotting the legs into the pegs used to attach  the rack to an ATV (or Training Tower).

I will talk more about this project later but for now, I’ll just link these videos I created to show the prototypes in various stages of development.

 

Update – Aug 15

Well that kinda worked, but only kinda. I redesigned the chassis (shrinking it significantly) to accommodate the USB-C port and it worked. For a while. I got the motor spinning and it spun gorgeously.

However, on repeated tries, the motor began to judder and stop. And the USB Power Bank I had shut down every time I tried it after that, and my plug-in USB power block’s blue light went out. Something is reaching the USB charger controllers and saying “Uh, there’s nothing there dude.” or something like that.

I highly suspect I’m burning out the motors. I am not sure what amperage USB-C puts out, and what amperage the motors can handle, so I am pretty sure this isn’t going to work. But it could have been a fluke.

I soldered in another motor and the exact same thing happened. Worked for a while quite nicely, but shutting it off and restarting it a few times resulted in a dead motor.

Oh well.

This, as with most of my new products, is in a prototyping phase, which is when you go down dead ends and find out what works and what doesn’t. 9V works, but the power doesn’t last long. 2xAAA works, but same. I’m going back to my original idea of 2xAAs and recommend buying rechargeable batteries.

At least I learned a little something about USB powering.

And also I bought a bunch of these little USB powered hand-vacuums at Dollar Tree that are wired into a USB (standard) cable and so I may just revisit the USB version of this later, with its own cord, since that motor seems to work fine, probably has some regulator on the circuit board or something I do NOT have with my Centrifuge.

I’ll keep posting updates here.