Alt-BEAM Archive

Message #12931



To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Sun, 2 Apr 2000 07:54:11 -0700
Subject: [alt-beam] Re: Wisker Circut


Hello Andrew,

Nice idea to use a piezo element for input, I imagine that the solder joint
is a little fragile. Tried a little epoxy?
But I have some questions about the circuit.

1. Do you need a transistor and the HC buffers?
2. Can the piezo be directly (with a series resistor) connected to an HC
input?
3. could you go straight (with a series resistor) from the transistor into
the PIC input?
4. What size capacitor do you use on OUT?
5. Try a different diode connection to give a dual time constant : fast
charge/slow discharge

regards

wilf


> -----Original Message-----
> From: Andrew Hooper [SMTP:andrew@best.net.nz]
> Sent: Saturday, April 01, 2000 6:53 PM
> To: beam@sgiblab.sgi.com
> Subject: Wisker Circut
>
> I have tested it and it seems to work on a PIC based robot, have not
> tried with a uCore yet.... thats the next job on the list :)
>
> If anyone sees any problems or can see a better way of doing this
> please let me know.
>
> The Peizo mods can be found at....
> kiwi.forge.cc/bots/
>
> Regards
> Andrew << File: feel02.gif >>



12932 Sun, 2 Apr 2000 13:27:39 EDT [alt-beam] Re: Ideas................. was --- Biped beam@sgiblab.sgi.com BUDSCOTT@aol.com In a message dated 4/1/00 10:49:11 PM Central Daylight Time,
SkavenArmy@cs.com writes:

<< Not an LED
Not a 22uF CAP
Not a photovoric unit with the hunger add-on
Not SPENCER
Just Jay-z
>>

hehe, i like that!

-Spencer

<http://www.botic.com/users/beamstop>

not a robot scientist
not a college major
not a grad student
not a professor
not a very organized person
just Spencer (isn't that impressive enough?)



12933 Sun, 2 Apr 2000 13:10:07 -0700 [alt-beam] Re: Reverser "'beam@sgiblab.sgi.com'" Wilf Rigter Simple case: Between the bicore outputs and a HC240 or HC245 motordriver.

H-bridge case: If you use a 6 transistor h-bridge, then buffer the reverser
output with an additional 240 stage or drop the reverser 47K resistor value
to 4.7K - 10K range in order to increase the drive current when in the
non-inverting mode.

wilf



> -----Original Message-----
> From: BUDSCOTT@aol.com [SMTP:BUDSCOTT@aol.com]
> Sent: Saturday, April 01, 2000 11:48 AM
> To: beam@sgiblab.sgi.com
> Subject: Reverser
>
> Okay, one quick question, how do you hook up a 240 Reverser to the motors!
> i
> got the circuit and i have a good understanding of how it works, but how
> does
> one hook up this circuit! Thanks a ton!!!!
>
> -Spencer
>
> <http://www.botic.com/users/beamstop>
>
> not a robot scientist
> not a college major
> not a grad student
> not a professor
> not a very organized person
> just Spencer (isn't that impressive enough?)



12934 Sun, 02 Apr 2000 17:26:28 -0700 [alt-beam] Almost Complete Walker alt-beam@egroups.com David Simmons Hey All,

Almost complete walker complete, almost.

I mentioned last week that Kyle (9 going on ten for those that don't
know) had started to breadboard the almost compete walker circuit of
Beam Online fame. I expected several failures the first time round due
to the pure number of connections. Consider, the addition of the two
H-Bridges, and LEDs to indicate gait. However he made only one mistake,
missing a pin with one of the .22uf caps, which didn't long for him to
debug.

The same day he started to layout the circuit on pref. board, was nearly
complete when he had to put it to the side for a few days. The week was
nuts so he wasn't able to get back to the project until yesterday.
Yesterday he completed the pref. board and the frame work and hooked it
all up with jumpers. At that moment he was ready failure, or at least
major problems. At first it just wiggled around in one spot, with a
quick flip of the connections for the back servo and it started to walk
across the table. He tested the reverse, and the started to finish off
the body etc.

Today he was busy right from the morning to get everything just the way
he wanted it so it will ready to show off to a few friends, grandparents
and so on. Making the tactile sensor, mounting it, mounting the battery
pack and so on.

For the entire project my involvement was limited to a little dremel
work, and paying for the parts. This one he wanted to do all on his own.

O.K. the proud Dad part is over.

There is some work left to be done, he plans on making some better legs
once he finds a better way to mount to the servos and gluing down the
power switch. Just little details like that.

Thanks to all the talk about the almost complete walker over the past
few weeks that I've been passing onto Kyle he was well prepared for the
problems that occurred and to avoid most of them all together.

Regards,
Dave

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