Introduction: Hydropower From Reuse

Picture of Hydropower From Reuse
Last fall we were staying at a holiday cottage generating its own electricity from a water wheel. We reproduced that in a little workshop with the kids, powering a LED with a miniature water wheel.

We made several attempts, a number of which worked, but those based on a stepper motors from a discarded printer proved to be the fastest an easiest to make. Furthermore, apart from some glue it was completely built out of discarded parts, thus combining the demonstration of renewable energy with reuse.

We had a great time building and playing. Check out the video to see the result in action:

Step 1: Reusing Parts and Materials

Picture of Reusing Parts and Materials
a small stepper motor as found in a printer
2 discarded CD-ROMs
a foam tray
some long stick (I used a piece of 20mm diameter  PVC tube from demolition)
one or two tie-wraps
a small piece of scrap paper

Non-reused: The only non-reused part is the hot melt glue (I recommend the low temp type, especially when working with kids).

Tools: scissors, screwdriver to disassemble the printer (not shown), cutting pliers or desoldering tools for (optional, not shown).

Stepper motors make very easy generators, as they produce relatively high voltages (I’m talking 5V range) at low rpm. Small DC motors (toy motors) need high rpm and still produce only a low voltage (1V range). Stepper motors do not need gears and/or electronics to power a LED (compare it to my junior wind turbine). I was worried about blowing up the LED at first, but that did not happen. The current generated being pulsating very probably contributes to that.
I doe not bother to waterproof anything (motor or electronics). Repeated use for several minutes, on several occasions, showed no need for that.
If found two stepper motors in an old Lexmark inkjet printer for which first the ink heads were no longer available and which later did not survive more than a couple of refills of the last ink head. I guess most inkjet printers will have two stepper motors, one for moving the paper and one for moving the head. The way to disassemble the printer will differ for each model. As in this case the printer should be a discarded one and there is no need to put it back together, you can’t do much wrong by simply unscrewing al screws you can find until you can free the stepper motors. Just keep the pinion gear and the connector they come with on the motors. To give you an idea on what to disassemble, you can go looking for an exploded view of your printer, like this one.

With a bit of luck the LED can also be found in the discarded printer. With even more luck you can find some discarded electronics with a LED standing tall on a printed circuit board, with most of its legs still intact, instead of mounted flush on the board. This makes it easier to remove from the print (leave the legs as long as possible) and easier to connect to the stepper motor by simply inserting it in the plug. As alternative you either us a new LED or desolder one and solder it to the stepper motor leads (I guess it is hard to tell if the ecological impact smaller for using a new led or for (de)soldering).

To keep within the spirit, you can also reuse tie-wraps: when you cut them loose carefully near the “ratchet”, you end up with a shorter, but still usable tie wrap.

Now to start building, see the next step.

Step 2: Wheel to Motor Connection

Picture of Wheel to Motor Connection

The wheel is made as light as possible. This makes any unbalance or eccentricity less critical.

One of the discarded CD-ROMs is put flat on the working surface. The glue will stick best on the printed side. Taking this in account we started with the printed side facing downwards.

The working surface as “seen” through the hole of the CD-ROM should be completely covered.  With the working surface protected like that, put a good blob of hot melt glue. The stepper motor is put with its pinion in this blob and kept in place by hand, while the glue sets (takes a minute or so). Before it has set look from above to check if it is positioned in the middle of the CD-ROM. Check from several sides to check it is level.

When you are two to do this, it is not hard to achieve a reasonably good alignment this way. The pinion gear helps and we found no spacers or templates were needed.

When the glue has set the scrap paper is peeled off.

With one stepper motor with a metal pinion gear, the wheel came off when using it. The pinion gear was glued back in the hot melt glue cavity, with superglue.

Step 3: Sandwiching the Vanes

Picture of Sandwiching the Vanes

8 vanes, roughly 3 by 3 cm are cut from the flat parts of a foam tray. You could try to use the curvature of part of the foam tray to your advantage (as a kind of scoop type vanes) but I chose not to and kept the water wheel and bidirectional.

The vanes are glued to the CD-ROM already on the stepper motor. We did not mark their position beforehand. Following the pattern show in the pictures, each time putting a van “in the middle” works accurate enough.

Some practical testing showed a second CD-ROM on top is needed to make the wheel-vane construction robust enough. When the glue has set, check the “height” of all vanes and trim those that are longer than the others. All vanes get some glue on top (working quickly) and the second CD-ROM is put on top.

Step 4: On a Stick and Into the Water

Picture of On a Stick and Into the Water
One or more tie-wraps are run through the stepper motor mounting holes and are used to attach it to the end of a stick. Take care the tie-wraps d not hinder the wheel of moving freely.

Connect the LED to two leads of the stepper motor by either inserting its legs in the plug or by soldering. The polarity of the LED does not matter as the current will be alternating. You will need to check which two leads work by spinning the wheel by hand. Several combinations will work, but (depending on the type of stepper motor) not all.

We were able to test our build in the feed to a real water wheel, but you can use any water running at a reasonably high speed. Be careful at the bank: don’t risk falling in the water.  :-) 


sonnyp99 (author)2016-10-05

Hi! I'm a senior in highschool and doing a project related to this as a part of a project. For mine, I am making a portable hydropower generator that can be used to charge mobile devices when camping. I was planning on making a stator and rotor to produce the electricity but seeing that I could use a motor, I am thinking of doing that. I am just confused about the motor getting damaged from the water because to generate enough power to charge a phone, the generator will have to be in the water for a very long time. You seem like you're much more knowledgeable on this topic so I was basically wondering if you had any tips on how you would go about doing my project. If so, please respond to this or email me at Thanks!

masynmachien (author)sonnyp992016-10-06

Hi Sonnyp99,

Cool project!

First, using a motor as generator is much simpler than build your own stator and rotor. Even commercial small charging devices (think crank torches, some of which can charge cell phones) are often based on an existing motor used as a generator. For a more high end applications it is very often a device specifically built with specs as a generator, but still with the same technology and on the same production lines as motors.

Most low voltage motors, including stepper motors do keep working in clean sweet water for days, weeks and even longer.
It does depend on the type of motor and it is hard to tell in advance.
But most do last quite a while, so if you only need to explore and demonstrate a working principle you can omit any waterproofing.
Dirty and in particular salty water will probably shorten the motor's lifetime considerably.

If however you want to demonstrate how a real reliable product could be made, you should waterproof your motor.
An accessible approach is using waterproof prop shaft assemblies as sold for RC model boats.



CristinB2 (author)2016-07-19

Hi. How long should each of the stator coils be in length? Thanks.

masynmachien (author)CristinB22016-07-20

Sorry, no idea.
I just scavenged a printer and used the steppers available from that.
I think it is not very critical if you just want to power an LED.

BorgesG (author)2015-10-20


masynmachien (author)2015-04-23


Hot melt glue is pretty common in DIY and in crafts shops. And Amazon is very reliable.

But you can use other glue, as long as it is water resistant, reasonably gap filling and doesn't attack the foam. If you use another light material instead of foam, you don't need to worry about the latter. You could make even use Duck Tape for the wheel and attach a piece of wood in the middle, with a hole that fits the motor axle or pinion.


sciencerobot (author)2015-04-23

Hi there,
Great instructable! Indeed..
Can u give me an alternative for hot glue as it is not available here. And i do not rely on and etc... No online shopping..

Kaine_KoG (author)2015-03-08

Great Instructable. Have you ever looked into the Tesla Turbine? This would be a neat project for it.

masynmachien (author)Kaine_KoG2015-03-11

Indeed, you could also use that type of turbine, but it is more adapted to flow in a confined conduit.

NicksonB (author)2015-02-21

Doesn't matter if the motor get wet?

masynmachien (author)NicksonB2015-02-22

Indeed, most motors will survive being wet, even being immersed, for a long time.

And the current lost through the conductivity of the water is negligeable at these low voltages.

4score (author)2014-03-06

Hi just a quick question.

Do you think it might be possible to attach 3 LEDs and have them light up when a different voltage is reached so kids can see how much energy is being generated and how fast the water is moving?

Oh yes thanks for the amazing instructables! Great ideas!!

masynmachien (author)4score2014-03-06

Thank YOU!
Great idea! That shoul probably work. If needed you can increase the difference in minimum voltage for different colours by adding diodes in series, like I did in this project:
Please keep me posted on your results.

AnnMarie Ha (author)2014-02-18


I'm not sure If this is too late but my daughter is making this for her school project and I was wondering if I could find such stepper motor on I was also wondering what type of foam tray I needed since we do not own any foam trays in our home and if we could buy any on Also, how long would this project take? My daughter has about a week to complete it.

Thanks, AnnMarie

masynmachien (author)AnnMarie Ha2014-02-19


you can probably find a stepper motor on Amazon. Make sure is is not a geared one, those are less suitable.
If a bottom price is not required, I would recommend this one:
At only $7 it not that expensive and I used that model with success.
The same product is also available through amazon, but at $9:
The shipping options might be better, but amazon and ebay are usually more expensive than buying directly from online suppliers. In this case Sparkfun is a certainly a serious company.

Once you know how to do it, building a working example takes only about an hour. But experimenting, improving and rebuilding it, can keep you busy for days.

As for the foam tray: you need a light and stiff material, that is water resistant for at least a while. So cardboard would not do. Any stiff foam in thin sheet or that you manage to cut in sheets under 1 cm would do. Foam board (stiff foam covered with paper) can work if you carefully peal off the paper. Light wood (balsa or poplar) will work too and should last a while at least.
Stiff plastic sheet, like cut from sturdier plastic bottles should work to. The curved shape can work well.
Please experiment. Anyway, be ready to repair the wheel once in a while. keep the glue gun at hand when the time for a demonstration is ready.



AnnMarie Ha (author)masynmachien2014-02-19

Thank You so much for replying so quickly! You're a lifesaver. Thanks!

AnnMarie Ha (author)AnnMarie Ha2014-02-18

Also, If I can't find a foam tray is there any other alternative as to foam? Like cardboard or maybe plastic?

abifabi (author)2013-11-24

Hello!, So this is my first time playing with electronics therefore struggling a little, I think i brought the wrong component ----> could you please recommend one with a pinion gear as im finding it difficult, without having to ruin my printer?! Would this be suitable? - Many thanks, Abi.

masynmachien (author)abifabi2013-11-24

Hello Abi,

The stepper motor you bought would be useable if only the gears didn't slip when you turn the axle. I altered one once, but that is not a beginner's job.

The maplin motors aren't stepper motors, so they will not do in the concept of this Ible.

this one will work:
I used one exactly like it once.

You do not need a pinion gear. If you have a piece of plastic or wood with a hole that fits the shaft tightly you can work from that. Or drill a hole. Even a drill bit with a diameter equal to the shaft will probably work to make a hole tight enough, if needed with some glue carefully added.

Still, if you ask around there is a good chance someone has a discarded printer lying somewhere.



abifabi (author)masynmachien2013-11-25

Hi Yvon,

Thanks alot for the response, help and link to the website. Yep the axle on the original stepper motor doesn't move. I was shown a miniature gearbox and brought that before i saw your comment from a local-(ish!) shop, would that be ok?! (trying to not open it, as im a student so funds are tight!!).

I was going to solder or wrap some bell wire to the end of the motor then wrap it around the LED.

Thank you


masynmachien (author)abifabi2013-11-25

Hi Abi,

The idea of this kind of generators is using a stepper motor, because stepper motors give enough power at relatively low rpm, so you do not need any gearing.
So to keep it simple you need a stepper motor and NO gearing.
What you show there is a DC motor (not a stepper motor, if not clear, look up the difference) with a lot of gears. That is another approach. You can make that work as a generator too, but it is mostly harder. The problem is that gearing is good to go from high rpm at the motor shaft to low rpm at an outgoing shaft. But the other way around (low rpm shaft to high rpm at motor/generator) only works well under certain conditions. As with increasing speed, the torque goes down, the friction become more and more of a problem. Keeping the friction down is not impossible, but not easy. If you still want to go the way of a DC motor approach, check out this ible: “”. As you can see it is in any case more complex. I did make a variant without joule thief and more gears with this motor: It is fairly simple, but mechanically rather fragile. And in contrast to most other motors, this type of “solar motor” breaks down when exposed to water.

As for the electrical connections: wrapping can work if you do it firmly. Soldering obviously gives a more reliable connection.



abifabi (author)masynmachien2013-11-25

Thanks alot for your reply and help.Will try the DC as a test model whilst im waiting and order the stepper for a nicer final one (third time lucky!)



brando134 (author)2013-08-27

I made a small hydroponic system for my wife in the kitchen, and this instructable made me think of a way to add it into the hydro system. As the water drains from the plants root container have something similar like this to convert the falling water into electricity. Would need a decent size motor but the aquarium pump only needs .03 watts to power, so this could be used to power the pump after fine tuning the fall rate of the water. Or could be used as a backup if the power went out, maybe?

masynmachien (author)brando1342013-08-28

Thanks for your interest. However I'm not clear on what you are proposing to do?
The energy you can get out of the drained water will be completely dependent of the height you can have it drop/flow (I suppose the drained water is not under pressure and has not much of flow speed).
A 0.03 Watt pump seems extremely low. Are you sure it is not 0.03 kilowatt i.e. 30 Watt, which is still low power, but beyond the approach I described. Maybe check the rated or measured voltage and current?
You're not suggesting to power the pump of the system from the water drained from the same system I suppose?
If you want a backup, I suggest a large water reservoir above your hydroponics.

tcase6 (author)2013-05-18

actually, ive never thought of it until now, but, if someone were to work this into their downspouts on their house, and depending on the size of generator possible,, may be extra electric on top of other systems like solar and such,,, if someone was brave enough to make numerous models and redesign a downspout to use these, could put them in a row creating even more... or even just something with enough power to charge your cell phone while on camping trips...." if you get service unlike we do "....

mosquemouse (author)2013-04-13

I will be doing this project soon. Just a question, though. I browsed online for "stepper motors" & I came across motors like this, so I just want to make sure if this would be right?

masynmachien (author)mosquemouse2013-04-14

Actually, that one isn't very suitable. The reduction means it needs a high torque to drive it (at low rpm). That could be used with a larger water wheel, but then I found out the output shaft quickly starts to slip in its gear, and the forces are no longer transferred to the actual stepper motor.

You can hack it, but then the actual stepper motor needs very high rpm. I managed to use one in a wind turbine by adding my own gears to the hacked stepper motor, but it became complicated and fragile build.

As far as I know. The cheapest you can buy and that do the trick
But it does need quite high rpm and therefor a fast water stream. Under a tap it just about works with good water pressure, full open and about half a meter below the tap.

The steppers stripped from printers actually work a lot better.

I've recently had good results with these geared DC motors powering a LED in a wind turbine:

It should work in a water turbine too. You will need to protect the motor from water, as in contrast to many other motors, these ones break down after having water inside.


camdog7d (author)2012-05-03

I have led underglow on my skate board and I thought I could power it by putting the printer motor by attaching it to my wheel so when I go the wheel will spin which will make the power light up the LEDs.

marcintosh (author)camdog7d2012-08-02

Dremel used to make a small mag powered light that went on the business end of the drill and would light up the work area. You could modify that to power your lights plus it's really tiny and wouldn't present any balance, drag, or size issues.
It's just a quick thought.

Stefanyk (author)2012-06-03

hi, i'm grateful to have found this site, i have a little project (for fun) but i don't have any skills on purpose.

i want to create a self powered "shishi odoshi" (a sort of japanese fountain).
by recirculating the same water with a recirculation pump powered by a hydraulic mill.

i made a gif to explain it:

my question is:how do I connect a mill to a circulation pump?
and more generally: how energy (in this case mechanical) can be canalized and used?

here i want ask if my project is possible, cause i don't know if such little turbine or with so little amount of water a recirculation pump can be powered.

thanks in advance

masynmachien (author)Stefanyk2012-06-03


Do I understand correctly you plan to drive the "hydraulic mill" with only the water pumped up? That can not work, as it would be perpetuum mobile.

Stefanyk (author)masynmachien2012-06-03

thanks for response.
mmm so i missed a little detail :P
then it's impossible to do it perpetual but for me it would be good in a finished perspective too, if it can go on for a few minutes or hours, it's ok.
what's the main problem? to what point the energy fails?
can work if I add water from time to time in the bottom tub?
or accumulating energy in some way: manually turning the turbine might accumulate energy, for example in a rechargeable battery then leaving it play for a few time.

can you explain better or reply to my questions?

masynmachien (author)Stefanyk2012-06-08

The bottom line is you will always loose energy at different steps and you can not win energy from nothing.

Adding water at the bottom makes no sense, as this brings no energy in the system. Adding water to the top could work. There are systems that use the energy of a large water flow to pump up a smaller amount of water to a higher altitude.

Obviously, powering the pump with a charged battery will have it run for som time, and you could recuperate a part of the energy with the turbine. Feeding this energy back to the battery or the pump would however need some decent control. My guess the energy gained would be rather limited.

I would suggest using an off-the shelf solar powered pump.

poofrabbit (author)2012-04-26

Hey congratulations on winning Scoochmaroo Challenge: Reuse!!!

masynmachien (author)poofrabbit2012-04-27


Lotusfalls (author)2012-04-27

Awesome instructable! Comprehensive, self-explanatory, and highly upgradable!

masynmachien (author)Lotusfalls2012-04-27


Kasm279 (author)2012-04-26

How dare you destroy that poor windows 2000 CD, what did it ever do to you?
Anyway, cool instructable and a neat idea for old CDs, it's given me some ideas on making a siren...

ehudwill (author)2012-04-22

Great project. I will have to try this one with my kids this summer.

masynmachien (author)ehudwill2012-04-26

Thanks! keep me posted on your success.

skelley4 (author)2012-04-26

I am going to make one..thanks for sharing

masynmachien (author)skelley42012-04-26

Great! I'm curious to see your result.

yeschiro (author)2012-04-26

Great instructable! If you could get this to have application in recharging electronics wile camping near a stream (cell phone, tablet, ipod, gps). That would be cool.

masynmachien (author)yeschiro2012-04-26


The stepper motor should be able to give enough power to charge such devices when using all coils and a rectifier. The wheel will probably need some upgrading.

Dave_DC2 (author)2012-04-26

You could also add angled vanes on the front, to become a wind turbine...! Great project, well done.

masynmachien (author)Dave_DC22012-04-26

A win turbine is actually how I started out :-)


rimar2000 (author)2012-04-21

Good project!

You could have more effectiveness gluing the vanes at an angle.

masynmachien (author)rimar20002012-04-22


In this case I wanted to keep it as simple as possible and have it work in both directions of rotation.

By adding the measurement of voltage and current it would make a good start to experiment on what works best.

How you hold it in the stream is also an important factor. Actually, when holding it with the "edge" only in the water flow, my guess is straight vanes aren't bad. For that kind of use the vanes could be made more narrow (run less deep towards the center), but of course it should remain strong enough.

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