Alt-BEAM Archive

Message #02567



To: Jakub Pietracha whraven@free.com.pl
From: Chiu-Yuan Fang chiumanfu@home.com
Date: Thu, 22 Apr 1999 15:32:20 -0700
Subject: [alt-beam] Re: PNC problems.


Here's how the PNC is supposed to work.

Vcc
|
|| 2.2M ohm resistor
|
| signal diode
--(1)----inverter--(2)--|>|---(3)--- PIN 1
|
= 2.2 uF electro capacitor
|
Gnd

At power up, the cap is like a short to ground so the input to the inverter (1)
is a low. That gets inverted (2) to a high and passes through the forward
biased diode (3). The high is applied to one neuron in the microcore and it
eats up all the processes going around the loop.
When the cap charges above the inverters threshold, the inverter output (2)
flips to a low. This is blocked by the diode which effectively cuts the PNC out
of the microcore loop. The process that was held at the neuron is released and
starts it's merry journey around the microcore.

Chiu

> Jakub Pietracha wrote:
>
> To all of you around the world. Help !!!
>
> I am a beginer in BEAM. I've just built my thirst BEAM bot - a two motor
> walker driven by a microcore of four neurons. And as you might expected I have
> a problem with it. The microcore worked for the thirst time and the walker
> walked perfectly but when I conected the PNC my problems begun. I've built my
> PNC this whay:
>
> gnd
> |
> ||
> || 2,2M ohm resistor
> | signal diode
> ------inverter----|>|------ PIN 1
> |
> = 2,2 uF electro capacitor
> |
> vcc
>
> It did something like this: at power up when the output of the PNC was high
> two pulses were runing around the net and when it turned low two neurons
> stayed high. When I changed the polarisation of the diode at power up two
> neurons stayed high until the output turned low and then two pulses started
> runing around the microcore.
>
> I've tryted everything: duble checked all components, used new ones, I've
> checked all the conections, replaced the IC (74HC14), played with polarisation
> of the diode and capacitor, tyed conecting C to gnd and R to vcc (in this
> configuration at power up the output was low and then turned high), removed
> all of the flux from the PCB but nothing helped. I've also tryed all types of
> diodes that I hapened to have in my part box but they all had the same efect.
> The timing is also not the problem I've used capacitors up to 100uF and
> resistors up to 5 M ohms. I just dont have any clue what could go wrong. I am
> rother advanced in electonics but it is the thirst time I am whourking with a
> microcore and I am realy confused.
>
> Afthur some time I've built completly new microcore and PNC from new
> components and a new PCB and even that didnt helped. Can anyone tel me what's
> wrong with it? <:o)
>
> Afthur some time I got fed up with that PNC design and decided to find my own
> solution:
>
> vcc
> |--------------------------------
> = 2,2uF electro |
> | |<---
> -----inverter-----------| PNP transistor
> | |----------------------------ex. pin 1
> ||
> || 2,2 M ohm
> |
> gnd
>
> It whourks but I steel dont know why I had the problems with the previous
> circuit.
>
> Jakub Pietracha
> whraven@free.com.pl
>
> Ps.
> Please excuse my english it is not my native lenguage and I dont use it as
> often as I would like to. Sory for all the mistakes.
>

--
Chiu-Yuan Fang
chiumanfu@home.com
ICQ=5614919
http://www.geocities.com/SouthBeach/6897/beam2.html

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