59592Re: [beam] Re: Headbot
- Aug 3, 2009Combining a headbot and symet is a great idea Martyn!
There are some interesting angles to consider.
A symet is a cross between a slider and a spinning top. WHen
it fires, it spins a bit and then shoots off in a straight
line, ending in another little
spin. The drive comes from the small diameter motor spindle
which has an effective wheel circumference of a few mils in
contact with the floor and which provides sufficient torque
to move the symet without using gears.
A symet is designed to rest on the motor shaft/spindle and
on one of (usually) three sides near its balance tipping
point. A solar cell mounted on the top of the symet would be
nearly horizontal and point nominally to an overhead light
source. No need to adjust the solar cell angle in that case.
In fact, a symet doesn't work very well with a side light
source, unless the solar cell can be adjusted to point to
the source. So when the symet stops moving, a side facing
solar cell is left oriented in a random direction. Then, if
necesary, the head circuit kicks in and adjusts the solar
cell to point to the light source to speed up the charge
With the right mechanical design, it may be possible to use
the symet motor with short pops, to incrementally rotate the
solar cell until it is pointed in the right direction and
take a full charge followed by a long pop.
Seen from a different perspective, a symet resting at a
steep angle, with the solar cell on top actually pointing
sideways, can function as a head by using the small diameter
spindle drive instead of a gear motor to rotate the solar
cell toward the offside light source.
Let me know what combination you are considering and
describe the present head circuit you are using. Note that
the head circuit should consume little power during the main
charging cycle after the head (solar cell) has be properly
----- Original Message -----
From: "martynharris@..." <martynharris@...>
Subject: [beam] Re: Headbot
Date: Mon, 03 Aug 2009 15:04:41 -0000
>Thank you Jab for pointing me in the right direction, looks
>a bit technical but hey, it's all a learning experience.
>Nice bug by the way!
>--- In firstname.lastname@example.org, "jabmechtech"
>> --- In email@example.com, "martynharris@"
>> ><martynharris@> wrote:
>> > Hi guys,
>> > I built the ol' headbot circuit over the weekend. I
>used a playstation 2 controller motor to make it move as
>the other motors I had were none responsive due to a lack
>of power from the bicore I suspect(though I'm still
>> > starting out).
>> > I bought a few 6.7V, 37x33mm solarcells from
>Solarbiotics and was wondering whether it was fairly simple
>to combine the symet and headbot designs to create a
>solarpowered headbot using a solar panel and some
>capacitors? I want to do this mainly to cut down on the
>> > weight of the batteries.
>> > Apologies if this information is elsewhere.
>> > Many thanks,
>> Sounds Like you want to build a FRED head.
>> I think it is in Wilf's files. two versions of it, if I
>> remember corectly. Or you can do the bare bones head, the
>Solarpowered smart head, wich is awesume, Hmmm, the list
>> goes on and on.. Jab
>> > Martyn.
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