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projects: testing this out...

  • so, current projects for stuff I am working, or have built:

    QuadRotor / RoboWasp:
    * Approx footprint: 1.25 meter (4 feet).
    * Approx weight estimate: 15-25 lbs
    * Estimated max thrust: 56 lbs (at 480 watt, or 12v 40amp)
    * Power Source: Have a 9Ah (24Ahr) LiFePO4 battery.
    * Bulk Construction: Wood, Cardboard, Urethane Foam, 3D printed plastic
    * Status: pretty early / slow-moving.
    ** Have some materials;
    ** Have begun experimenting with 3D printed propellers and gearboxes for it.
    * Uncertain:
    ** Switch from batteries as primary power-source to a small ICE
    *** Chainsaw engines are cheapest, but reasonably large/heavy (approx 12 lbs, + fuel).
    **** May imply increasing power-profile to compensate (24v 1.0-1.5 kW ?).
    **** May need bigger motors/... if going to higher power.
    **** Otherwise, need to find a reasonably small/cheap chainsaw engine.
    *** An RC engine would put out sufficient power for the current size range.
    **** However, RC engines are more expensive than chainsaw engines.
    **** RC 4-cycle gas engines are particularly expensive (vs "nitro" engines).
    *** Issue is mostly that a 9Ah battery will limit flight times to a matter of minutes.
    **** Bigger batteries could also work, but:
    **** A large bank of LiFePO4 or LiPo/LiON cells would cost more than using an ICE.
    **** NiMH would be a little cheaper, but have a harder time producing large amperage.
    ***** Would need 3x10 or 4x10 NiMH D-Cells to deliver power, or around $200 worth of batteries.
    ****** So, around similar cost to using an RC ICE.
    **** Should still be cheaper than LiFe or LiPo cells at least.

    CNC Milling Machine:
    * Outer size estimate: 24x24x40 inch
    * Table Size: ~12 inch.
    * Power Source: PC / ATX power supply.
    * Status:
    ** Need to build box and physically assemble it.
    ** Main issue ATM is getting the wood cut up into the appropriate sized panels, and getting it assembled.
    ** Partial Reason: Need tools to cut and drill the wood (out of scope of small hand-tools and a hacksaw).
    ** It is outside what is viable to build out of cardboard.
    ** Spinning motors/etc, not much use without the box and structural parts.

    Cardboard Box Robot:
    * Size: Approx 20x24x12 inch.
    * Weight: about 12 lbs (includes 6lb PbAc battery).
    * Approx power: 1/10HP (uses about 100W of power though during operation, and about 9W when idle).
    * Power Source: 9Ah 12v PbAc UPS battery.
    * Construction: Cardboard, 3D Printed Plastic, Duct Tape and Hot Glue.
    * Status: Built / Works
    ** Has a webcam for remotely seeing from the POV of the robot.
    ** Have a shell for it, want to paint it to look like a ladybug, but don't have any spray paint.

    cardboard box robot was mostly so I could at least have *something*, and to test out some initial technologies for the further-reaching quadrotor project. it is actually the newest of the projects...

    for the box-robot, it uses 3D printed gearboxes which reduce output to 400RPM, which drives the wheels.

    the quadrotor propellers (early test forms) use 6000RPM output, as simulations implied that 6000RPM with a shallower pitch would be more efficient than 4000RPM with a steeper pitch in terms of producing thrust.

    the "new" propellers (still need to 3D print them), will be about 14 inches and have an 8 degree pitch. they should (hopefully) generate some thrust and not break apart.

    (ADD / UPDATE: got some lift briefly with the new propellers, but gearboxes soon failed pretty hard as all the gear-teeth turned to dust... some research: this is apparently way too much power to be running through the small contact areas on ABS gears... would at least need nylon, but even then I am apparently pretty near the point where metal is needed...).

    had tested with some propeller designs I had got off the internet, but the thrust is nowhere near sufficient (and I reach full voltage across the motors and amps level off, meaning the propellers are not converting enough of the power into thrust, and are basically free-spinning).

    sometimes does seem like all this is basically pointlessly frittering time away...

    as evidence of how slowly all this is going:
    when I started the quadrotor project, the newest Raspberry Pi was the Model B.
    now, there is the Raspberry Pi 2 (and the B+ and A+ had been released in the meantime).

    so, yes, very slow project...
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