- Aug 6, 2009Hi Wilf,
Apologies for the delay in getting back to you.
Thank you for the extra details. I'm afraid I'm just starting out, and I've only built the symet and the headbot, after which I was sitting there and wondering whether I could put the two together (in a rather child like fashion) ;-)
I was looking at your very impressive smart head, and think this is the kind of circuit I want to use, i.e. I was looking for one where the headbot is completely solar powered, being powered by a similar circuit to the symet in order to avoid batteries and the additional weight they add to the bot.
I like your idea though, with the reverse; a head bot mounted to a symet. Definitely food for thought. May be I could simply glue a small headbot to the symet and have it feed in to the motor of the symet?
As an aside, the 74AC240 IC used for the head bot amplifiers/buffers the signal to strengthen it in order to power the motor, what stops me from using it as an audio amp like the LM346 or Op-amp? Or is it simply not built to handle this kind of input? (Should I raise this as a separate post?)
Thank you Jab and Wilf for your help, I really enjoy sticking things together and seeing what comes out of it.
All the best to you.
--- In firstname.lastname@example.org, wrigter <wrigter@...> wrote:
> Combining 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@...>
> To: email@example.com
> 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!
> >Many thanks,
> >--- In firstname.lastname@example.org, "jabmechtech"
> >><jabmechtech@> wrote:
> >> --- 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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