Alt-BEAM Archive

Message #09853



To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Sun, 06 Feb 2000 20:29:46 -0800
Subject: [alt-beam] Re: Instead of 74x14 for Microcore..


Kelly Petriew wrote:
>
> ... Is there a need to pump the Microcore faster? What
> advantages/disadvantages would this have? Is it more efficient?

Hi, Kelly.

Typically, the "speed" of a logic chip refers to how quickly it can
respond to a change in the input signal. Same idea as a Pentium 33 vs. a
Pentium 233 vs. a "whatever the heck they are up to now".

This is important if your circuit is changing very quickly. In BEAM,
just the opposite is true. A microcore responds vvveeerrryyy slowly. So
slowly, in fact, that we need a Schmitt trigger instead of an ordinary
inverter.

So there is no particular advantage (or disadvantage) to having a fast
Schmitt inverter.

Regards,
Bruce



9854 Sun, 06 Feb 2000 22:04:51 -0700 [alt-beam] Re: Motor specs beam@sgiblab.sgi.com Dave Hrynkiw At 06:50 PM 2/6/00 , Phillip A. Ryals wrote:
>The low rpm and low torque made me think twice. But I've never really
>looked at servo specs, so I don't know how to compare them.

Looks like 11 in*oz of torque, which is about 1/4 that of a standard hobby
servo (about 40 in*oz). I'd jump on them anyways.

Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com



9855 6 Feb 00 23:07:03 CST [alt-beam] Re: Instead of 74x14 for Microcore.. beam@sgiblab.sgi.com Steven Dang I'm assuming the same thing applies to bicores and pretty much most beam
applications right? So faster isn't better?

Steven

> Typically, the "speed" of a logic chip refers to how quickly it can
> respond to a change in the input signal. Same idea as a Pentium 33 vs. =
a
> Pentium 233 vs. a "whatever the heck they are up to now".
> =

> This is important if your circuit is changing very quickly. In BEAM,
> just the opposite is true. A microcore responds vvveeerrryyy slowly. So=

> slowly, in fact, that we need a Schmitt trigger instead of an ordinary
> inverter.
> =

> So there is no particular advantage (or disadvantage) to having a fast
> Schmitt inverter.
> =

> Regards,
> Bruce


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9856 Sun, 06 Feb 2000 21:47:45 -0800 [alt-beam] Re: Instead of 74x14 for Microcore.. beam@sgiblab.sgi.com Bruce Robinson Steven Dang wrote:
>
> I'm assuming the same thing applies to bicores and pretty much most beam
> applications right? So faster isn't better?

For the basic applications ... bicore, microcore, etc. BEAM is very
slow. I have experimented with less traditional applications of
BEAM-type neurons which are much faster, but I have never come close to
the speeds these chips can handle.

The speed of the chip is not a major consideration unless you are
getting into very exotic stuff.

What you will be interested in is things like:

- how much current does the chip draw?
- how much current can it supply to operate motors, etc. ?
- how susceptible to static is it?
- does it have the same pinout as the commonly used BEAM
chips? And if not, are data sheets easily available?

Regards,
Bruce



9857 Mon, 07 Feb 2000 01:12:35 -0500 [alt-beam] Re: My first Photovore beam@sgiblab.sgi.com, dilbertpete@yahoo.com "FCO Enr." greetings Pete,

Actually it turns out that my wiring was perfect since
the beginning, the reason nothing was working was because I
had expected it to take max 5 seconds under a flashlight to
power up the solarengine and trigger! But it takes more like 20
under a 60watt lightbulb.

Problem is, it seems like both sides work cause when
I reverse one IR sensor one side spins and when I reverse the other
the other side spins. I haven't been able to get both spinning!

I'll recheck my connections and I put the + side (long leg)
of sensor to Pot but still only one side works, until I reverse them.
I tried turning the pot from 50k to 0, still same side. 50-100, still
same side. It's weird. I must have something else reversed somewhere.

Andy

*********** REPLY SEPARATOR ***********

On 06/02/00, at 2:18 PM, Pete McCarthy wrote:

>Hello again Andy,
>
>I know how difficult it is to complete a photovore. It was very
>frustrating for me when mine turned out to be a failure (which is now
>sitting in my junk drawer). Usually it turns out that the stupidest
>mistake costs you hours of circuit checking. The first time I tried, I
>had the transistors in reverse and it took me quite a couple of rebuilds
>to figure that out. As for testing motors, just put 3 volts across it.
>(connect 2 AA batteries to it) The pot needs to be configured AFTER the
>robot is working and the middle varies on the pot (It's probably either
>10 or 15 turns). And for the ir sensors, the longer pin is the
>positive. I hope this solves your questions. If you have any more,
>feel free to email me.
>My address is dilbertpete@yahoo.com
>
>Hope you get your first photovore working,
>-Pete
>--------------------------------
>http://members.xoom.com/Star_BEAM
>
>"FCO Enr." wrote:
>>
>> Greetings Pete,
>>
>> Thanks for your reply! I am using parts which were ordered
>> from Solarbotics and I am sure the motors are efficient. I am also
>> pretty sure it is some mistake of mine rather than defective components
>> that is causing me such irritation.
>>
>> I am learning a lot about electronics just putting this little
>> kit together and I guess my question is, if you've put the circuit=
together
>> 4 times already and checked all connections and still nothing.. what
>> do you do then? How can I test the motors.. you know just get them
>> spinning so I know they work? What is the valid range of the 100k pot
>> so I could determine what the middle is (it just spins endlessly in both
>> directions), for the siemmens IR1 sensors what is the leg which goes to
>> the pot? the long or short one? ( I tried one in one direction while the
>> other reversed just to see if one side worked but nothing). etc..
>>
>> Thanks again for the reply.
>>
>> Andy
>>
>> On 05/02/00, at 11:25 AM, Pete McCarthy wrote:
>>
>> >I really think that the problem is your motors are inefficient. That
>> >was the cause of my photovore failure, and could be one reason why your
>> >photovore isn't working. If it were a bad part, then probably only one
>> >half of the robot would work while the other would function perfectly.
>> >-Pete
>
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>Talk to your friends online with Yahoo! Messenger.
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9858 Mon, 7 Feb 2000 18:31:55 +1100 [alt-beam] infra red "HENDO" Hi guys and girls,

I was wondering if anyone had a circuit for a short range remote control
(30cm) that uses only one emitter and one receiver diode with up to 10 (pref
5, less will do) switches.

thanks

James

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