Alt-BEAM Archive
Message #12148
To: beam@sgiblab.sgi.com
From: Ben Hitchcock beh01@uow.edu.au
Date: Mon, 20 Mar 2000 07:43:48 +1100 (EST)
Subject: [alt-beam] Re: FRED circuit (beginner)
> Hi everyone,
>
> I just completed the FRED photopopper circuit. I have one problem though. I
> am feeding 9v into the circuit but either only one motor turns on or they
> both just stutter...
>
> Any ideas. When I put a jumper from the collector of NPN to ground both
> motors work, but I am afraid this is bypassing some parts of the
> circuit...Any ideas? I don't think it is a defective NPN, it worked on the
> breadboard...
Yes you are bypassing some of the circuit - ALL of it! *grin* To power
the circuit from a 9V battery, connect up a 1k resistor in series with the
9V battery. This will keep your motors from burning out and stop your
poor little 9V battery from having a hernia. You will still need a 4700
uF or so storage cap.
The motors will kick over pretty quickly with a 4700 uF cap - this might
be the 'stuttering' you were talking about.
To make the circuit 'fire' manually, short out the FLED. This should test
most parts of the circuit. If this doesn't work, put a 470 Ohm
resistor in between the PNP base and ground. If that doesn't make it
fire, try putting the 470 Ohm between the positive terminal of your
main storage capacitor, and the base of the NPN
transistor. Following these tests in this order will help me (and others
on the list) figure out what, if anything, is wrong with the circuit.
hth,
Ben
12149 Sun, 19 Mar 2000 15:49:57 EST [alt-beam] Re: GOLD MINE!!!!!! beam@sgiblab.sgi.com BUDSCOTT@aol.com awesome, let us know how the turn out! wish that happened around here more
often!
-Spencer
12150 Sun, 19 Mar 2000 15:46:30 EST [alt-beam] Re: Funkie Bicore beam@sgiblab.sgi.com BUDSCOTT@aol.com Check your timing caps and resistors! the tolerance ratings can severly
affect the bicore movement! it sucks, but you might need to use some trimpots
in series with resistors to adjust it, or just use rubber bands to assist the
bot in keeping its leg under him!
-Spencer
12151 Sun, 19 Mar 2000 13:00:31 -0800 [alt-beam] Re: The future of robots "beam@sgiblab.sgi.com" "iphotope@botic.com" I apologize. I didn't mean that nobody else should
have their opinion, just that I don't want to get swamped
again by e-mails repeating what someone has already
said. If you would like to continue this discussion with
me, send it privately to iphotope@botic.com
Iphotope
12152 Sun, 19 Mar 2000 11:35:35 -0500 [alt-beam] Re: Yes!! [not for advanced people with no time for beginner junk.....] "William Cox" Hmm ... I first made a different type pvore with a perf board. It was pretty
bad. I sorta balked at freeforming, but I found it quite easy. It looks
great too. I'm using two 2200uf caps in parallel. I forgot to add the 47uf
cap. I'm just using some MPJA pager motors. My bot is also very funky in
that some times it stops responding until I reverse the power briefly.
Weird. It also happed w/ the other pvore, and that was a totally different
circuit. Maybe it's my Rat Shack caps.... Thanks.
-William
PS. I own and operate a webpage abut robotics. You think Kyle would be
interested in writing a little tutorial about how to make a head or
something? I think my readers would like it.
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