Introduction: OpenFuge

The OpenFuge is a relatively low cost open-source centrifuge for DIY biolabs and biohackers. It primarily uses commercial off the shelf parts with a few custom electronics. It aims to enable anyone to perform biological experiments, not just those with access to specialized labs.


Specs (Observed):
G-Force: 6000 G's
RPM: 9000 RPM
Size (closed lid): 15cm x 24cm x 20cm
Weight: 1.6 kg
Power Source: Four 18650 Lithium cells
Material Costs: $200


Features:
Adjustable speed and power
Can hold up to 4 Eppendorf tubes
Portable
Safety Interlock
Cleanable
Live RPM monitor and countdown



For DIY people head over to http://www.thingiverse.com/thing:151406/#files  and cut out the attached panels. Check out the Bill of Materials (BOM) for the list of parts needed. WARNING: LASER CUTTER REQUIRED (40 min)


For non-DIY people head over to https://www.tindie.com/products/CopabX/openfuge/ and purchase a kit. It comes with all electronics pre-soldered and pre-programmed.



Step 1:

Step 2: Creating the Frame

Laser cut the files from Thingiverse. Make sure you have the smooth side of the wood facing the right direction.

If you do not have a laser cutter, you can print out the .dxf templates on paper. Tape the templates onto the material specified for the pattern, then cut the pattern on a scroll saw.


An optional step before assembling the frame is to apply a hydrophobic coating onto the parts of the hardwood frame that could be exposed to liquids. This makes for easier clean up in the event a tube shatters or aspirates. If you cannot find a hydrophobic coating, a heavy coating of enamel spray paint will also work.

My layer sequence:
3x Black Enamel Spray Paint
3x Hydrophobic Base Coat
3x Hydrophobic Top Coat

Step 3: Frame Assembly

Attach the base plate, front plate, and back plate via the slots. Take special notice to the way the base plate is oriented in the pictures, IT IS IMPORTANT! Then screw the panels together. Do not tighten them fully as it will make it difficult to attach the side plates later on. 

Notice the way the nut slots into the base plate and the way the panels attach. This is how almost all of the frame is assembled. If you have difficulty inserting the nut, use a plier or tweezer.

Step 4: Frame Assembly

Attach the side plates. Before fully tightening all the screws, slide the kill switch and battery pack wires through their designated slots.

Step 5: Battery Attachment

Using double sided tape, attach the battery pack.

Step 6: Frame Assembly

Attach the hinge plates as shown. Then add the endstop screws, making sure to fully tighten them. Make sure to push the endplates as far toward back (away from the back plate) as possible as this will cause the lid to lock into place when closed later on.

Step 7: Electronics- ESC

Attach the electronic speed control.

Step 8: Electronics- Control Board

Remove the nut and washer from the rotary switch. Then insert the board as shown. After the board is aligned, screw on the washer and nut from earlier to hold the board in place.

After the board is secured, insert two screws into the holes on the upper left and right of the LCD. Use lock nuts instead of regular nuts, and be sure to not tighten the screws fully: the screws are not the main attachment method.

Add the rotary switch dial pieces. There should be two of them.

Once done, attach the ESC signal cable and power cable. Be sure to follow markings on the board (black -, white signal, red +).

Step 9: Electronics- Motor

To assemble the motor module, you will need a Phillips (+) and flathead (-) screwdriver. Attach the motor mount and motor collar as shown. Do not worry if the motor looks backwards, it is an outrunner motor which means the outside of the motor is meant to spin, not the inside axle.

Add a piece of black tape to the outside of the motor. This will serve as a contrast so that the RPM sensor can function.

Step 10: Electronics- Motor

Attach the motor to the base plate as shown.

Step 11: Electronics- Motor

Attach the bullet connectors as shown. The order does not matter.

Step 12: Hub Mounting

Attach the hub to the motor as shown. Do not forget the washer.

Step 13: Electronics- RPM Sensor

Attach the RPM sensor as shown (nuts not necessary, the plastic should be threaded). Use a piece of tape to block half of the sensing area to block the IR light being emitted. 

Adjust the sensor position until it is about 3mm from the motor. Lock the position by tightening the mounting screws.

Step 14: Lid Assembly

To assemble the lid, first attach the front and back plates of the lid to the top plate of the lid.

Step 15: Lid Assembly

Attach the side plates of the lid, they are identical. Screw the lid together.

Step 16: Electronics- Safety Switch

First thread the socket end of the touch switch through the slot in the base plate as shown in the picture.

Mount the switch. Before fully tightening the screws, slide the switch position so that it triggers when the lid is closed.

Step 17: Frame Assembly- Lid

Attach the lid to the hinge plates on the back of the frame. Use lock nuts instead of regular nuts and take care not to fully tighten the screws so that the lid freely rotates.

Step 18: Electronics- Wires

Simply attach the wires as shown. If desired, zip-tie unruly wires using the mounting holes in the left frame plate.

Step 19: Frame Assembly- Bottom Plate

Attach non-slip pads to the bottom plate in the configuration shown. Then attach the plate to the frame as shown.

Step 20: DONE!

That's it! Your centrifuge should be fully functional. Charge your batteries and take it for a spin (no pun intended).

Comments

author
Pier PaoloB (author)2017-06-02

Hi, great work!

I want to try to make it, or to make something similar with 25.000 rpm.

I don`t know how I can calculate the right power of the motor if for example I want rotate 100 grams with 25.000 rpm.

How have you calculate your one? I saw your motor has 2.200kv and for 11.1V the rotations would be 24.420 (100%), and your centrifuge can rotate for 9.000 rpm (36%)

Which is the weight you calculate to put over the motor? Is there a way to calculate how many rpm lose a motor with a particular weight?

Thank you in advance

Shadsu

author
skybluecat4000 (author)2016-04-08

Great instructable! Thanks!

A large part of the cost is for the motor (Approx $34 US) and speed controller (Approx $30 ) . I wondering why you chose those parts. I'm thinking of substituting a cheep DC motor and motor controller (Approx $5 each), do you see a problem with this.

Thanks again for the excellent instructable!

author
2937214 (author)skybluecat40002017-05-24

Yea, I was thinking that too.

author
silm (author)2017-04-22

Impressed with your work good technique to create this one

author
kyle brinkerhoff (author)2013-11-06

it would be cool to see it equipped with some sort of vibration sensor to stop a catastrophic failure if its unbalanced

author

That's a great idea.

author
wikd (author)2015-08-28

Thank you

author
vandumas (author)2015-04-08

Great work

author
toddadams (author)2015-04-06

Wooowww.... Keep it up..

author
undanganpernikahan (author)2015-03-22

Low cost lab tools. Awesome <3

author
jthomson3000 (author)2015-03-09

Impressed art work. Thank you.

author
jthomson3000 (author)2015-03-09

Impressed art work. Thank you.

author
stett (author)2013-12-12

This is really cool! But I'm wondering if there's anyway to make something with more capacity for separating things in the kitchen. I'm really getting into modernist cuisine and they use a centrifuge for things like separating out the "tamari", oil, and "miso" from these nut fermentations (http://www.ediblegeography.com/the-misofication-of-manhattan/). It wouldn't really be practical to do in such small amounts. If I did a ferment it would probably be the capacity of a mason jar. Any ideas in how to build something at a reasonable cost with larger capacity?

author
CopabX (author)stett2013-12-13

I doubt that there is any way to spin a mason jar as the largest centrifuges I've seen spin samples half that size. I was thinking a disc or handcrank design, but I would need to know how many xG's are needed to separate the oils. You could always make a jig for a car wheel or washing machine and spin the jars that way...

author
mdeblasi1 (author)2013-09-17

Just yesterday, in the Kitchen, trying to separate tomato "plasma" from tomato solids, I said to myself, I wish there was such a thing as a kitchen centrifuge.

author
gumby_kevbo (author)mdeblasi12013-09-20

When I asked the GF where the lettuce centrifuge was, she didn't know. Then I found it. Turns out is called a salad spinner. If you could find some containers to fit, it might work for the tomatoes.

author
Bill WW (author)gumby_kevbo2013-11-23

From now on it is a "lettuce centrifuge" in our house. Until complaints from the GF become too great.

author
toyotero (author)2013-10-22

I just saw an article on popsci blog covering this device and your work.
Congrats on developing a great device.
http://goo.gl/RlC6pr

author
GS104 (author)2013-10-09

This is one of the best things Ive seen on this site. Concept+directions+problem solving together with your support comments/logic are all A1. Great Job.

author
CopabX (author)GS1042013-10-10

Thanks!

author
dlebryk (author)2013-09-17

Great instructions. The build looks really cool.

I didn't notice a mention of safety concerns with this build. It has been a million years since I bought or used one of these - I used to use them every day. I recall that the commercial versions of these Eppendorf centrifuges usually have a cast circular body around them. In the event the rotor flies apart they can contain the parts. They also have a limiter for out of balance - oddly way too easy to get them out of balance accidentally (whoops I forgot a test tube, or I didn't add the 1 mL water to the counterbalance tube). I'd hate to see this ramp up and the motor go flying off the mounts.

Kudos on a really nice looking instructable.

author
CopabX (author)dlebryk2013-09-17

Thanks! I'm glad you like it.

Concerning safety, I've stress tested the fuges for up to 15 minutes fully loaded and haven't experienced anything problematic. I've also purposely destroyed the petals (poking sticks or running REALLY off-balance loads) to test the frame and center hub (which is why it only holds 4, not the usual 6 tubes) and found the wood and 5.5mm acrylic sheets hold fine. I have a safety switch to make sure it doesn't power up without the lid being closed, but I'm sure someone will just put a piece of tape over it. I'm also sure that the motor will hold since it is usually used for helicopters and gigantic rotors. I've seen these things smash into the ground and only have a slight wobble afterward.

I do have a backup plan, though, if problems do arise. I have plans for an adhesive mylar film to act as further protection on the acrylic sheets. The film is usually used for hurricane windows, so I'm sure it will work, too.

As for the balance sensor, I haven't come up with a way to sense an uneven load without having expensive sensors. It's a great idea, though, and I'm open to suggestions.

author
ecochran3 (author)CopabX2013-09-18

Have you thought of using an accelerometer as a balance sensor? You can get them for under $2 (not including shipping) from DigiKey, for starters. Just monitor it for spikes of excessive lateral acceleration, and especially spikes that gradually increase, such as those due to resonance. Of course, you'd need to determine a good baseline for normal readings due to vibration, but that should be enough to get you started.

author
yellowcatt (author)CopabX2013-09-18

I wonder if polycarbonate or PETG would be a better choice for the cover? Much more shatter resistant than acrylic.

author
CopabX (author)yellowcatt2013-09-18

Honestly, PETG is my favorite plastic.The only problem with it is that it burns when lazed and turns yellow. Then it isn't dimensionally accurate. I also thought of using Delrin, but then the lid wouldn't be clear.

author
biotoscano (author)2013-09-18

Hi! Have you considered to use a reed relay and magnets to control RPM?

author
CopabX (author)biotoscano2013-09-18

The speed is already controlled by a PWM signal.

author
juliamorley (author)2013-09-17

You should approach someone who is involved with medicine in developing countries - an affordable and almost flat-pack centrifuge could be something that their clinics could probably use :-)

author
spylock (author)2013-09-17

Well done,Im impressed.

author
jtechian (author)2013-09-17

Nicely done.. I was thinking of doing one a little bigger. What I have in mind is for reclaiming cooking oil by centrifuge to remove all solids from the oil.
Thank for re-inspiring me to get busy :)

author
Nickson Yap (author)2013-09-16

Man, I've been trying to find ways to measure RPM from non-sensored brushless motors.
There are ways to use hall sensors.
I've thought of using an optical sensor but I've never thought of such a simple way!

author
CopabX (author)Nickson Yap2013-09-16

I'm glad you like it. It was really easy to test sensor setups using the MSO-19 from Link Instruments. I tried a bunch of different ways of optically sensing the RPM (reading petals, reading center hub, etc.) but a passive IR sensor reading the main body ended up being the best.

http://www.linkinstruments.com/mso19.htm

author
spyder2021 (author)2013-09-15

looks cool, but what is it? Can you include a video of it working?

author

A centrifuge is a machine used to seperate organic matter of different densitys by centrifical force. Ex. Red blood cells from plasma.

author
diy_bloke (author)2013-09-16

I am all for DIY, even if sometimes you can't make it much cheaper yourself, but considering that laboratory centrifuges are available starting at around 50 USD, you got to be really dedicated to spend 200 USD on a DIY, espcially if it is a kit :-)

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