The Almost Useless Machine

Posted by on Sep 24, 2012 in misc | 13 Comments

We all know, we should use more renewable energy. Here is my contribution. Use solar power if you want to cut 20mm wooden rods. And plan ahead because it may take a while.

This little machine uses a so called solar engine to drive the motor. This solar engine is able to collect tiny amounts of energy over time and stores it in large capacitors. When the voltage reaches a certain level, it opens up and uses all the stored energy at once to drive a motor. These engines were used to drive tiny BEAM-bots and were quite popular a while ago. A lot of information can be found at beam-wiki.org on how to build them and how they work.

Parts

Operation

The machine works fine. That is … most of the time. Sometimes the solar engine locks up in the state where it dumps all the energy to the motor. It works like this:

  • The two solar panels charge the capacitors until they reach ~2.85 V.
  • The 1381 drives the transistor open and the motor starts turning
  • The voltage drops until 1.1V, the motor stops turning
  • Now there maybe a balance between the solar panels to provide enough current to hold the voltage and the motor on the other hand, not consuming enough.

In the video, there was bright sun light. With that, the machine runs quite well, even without having to pause to collect more sun light. In that condition, I’m quite sure, it would have worked without the solar engine.

To solve that, there are a couple of other solar engines on the BEAM wiki, that I can try, even if most of them were not designed for this high power use case. If someone has any tipps or hints, please add a comment below.

Links and Downloads

13 Comments

  1. florinc
    25. September 2012

    Great contraption!
    You should offer it as a kit, I bet there are many people who would be interested (me included).
    (Same for the 2 euro machine.)

  2. The Almost Useless Machine « adafruit industries blog
    25. September 2012

    [...] tinkerlog.) We all know, we should use more renewable energy. Here is my contribution. Use solar power if you [...]

  3. Kevin
    25. September 2012

    take a while, how long, even in full sun? looks like there’s very little pressure on the blade, might take months?

  4. Alex
    25. September 2012

    Yes, months at least. Especially in rainy Hamburg.

  5. MAKE | Solar-Powered Dowel Cutter
    25. September 2012

    [...] love this elegant if “almost useless” machine that Alex Weber created: This little machine uses a so called solar engine to drive the motor. This solar engine is able to collect tiny amounts [...]

  6. Sam Juvonen
    26. September 2012

    Brilliant! I have to build one… and thanks for the link to BEAM wiki, I didn’t even know this was a Thing.

  7. chriss
    27. September 2012

    hi from Frankfurt,

    can you give a tipp how to create/construct this gears you use? i am a portal cnc newbie and would love to are able to create this by my own.
    cool project ;)

    regards
    chriss

  8. Alex
    28. September 2012

    Hi Chriss,
    I used this one http://www.thingiverse.com/thing:3575 and then extracted the outline with OpenSCAD and imported it into QCAD.
    There is also a gear tool in inkscape that you may want to try.
    Cheers,
    Alex

  9. Zack
    1. October 2012

    I’d definitely buy this in a kit. You could test the waters by making a kickstarter project.

  10. Mike
    3. October 2012

    I’d buy it as a kit, or constructed. It would be the coolest gift for my dad.

  11. MattWPBS
    3. October 2012

    Want this to go with my Ultimate Useless Machine: http://frivolousengineering.com/?page_id=750

  12. Chad
    3. October 2012

    Awesome just Awesome !!! Really cool display would love a kit of this this is just too great !!

    keep up all your cool projects

  13. Vik Olliver
    5. October 2012

    So this could power what kind of water pump? :) Seriouslky, though, it might power an Archemedes’ Screw well enough to pump some water before it evaporates :)