Create a Pulse

[George Sephton]

Hi,
This isn't really to with a PICAXE but Im using a 4017 decade counter and many know this isn't "userinputfriendly" ie Click a button and it'll pulse about a million. This is overcome on the picaxe with a simple "pause 500" but how can I do this the analogue way. So I can have a push button connected directly o CLK of the 4017?
Thanks,
George.

 

[eclectic]

George.
Just checking.
Have you read

http://www.kpsec.freeuk.com/components/cmos.htm#4017


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[George Sephton]

Does this mean something?
The ÷10 output is high for counts 0-4 and low for 5-9, so it provides an output at 1/10 of the clock frequency. It can be used to drive the clock input of another 4017 (to count the tens).

Ive read it but maybe I didn't understand it.

 

[Andrew Cowan]

Say you want a two digit display. The tens digit needs to count 10 times as slowly as the units. Thus the 4017 has this output for driving another 4017. Ignore it if you don't need it.

A

 

[sketchy]

Hello
Please take this with a pinch of salt but it may be worth looking in to.

Is the reason for the lots of pulses this thing called bounce. Because i have just been reading about button things and somone said that if you put a capassitor across te switch it can stop bounce.

I hope this is of use.

Joe.

 

[George Sephton]

I have heard that, I'll look up a debouncer circuit.

 

[eclectic]

Here's the page from the book
of magic spells.

http://www.datasheetcatalog.org/datasheets/320/499984_DS.pdf

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[sketchy]

Woo Hoo

Did I get it right
That is the first advice i have ever given

i read it here

http://www.picaxeforum.co.uk/showthread.php?t=10864&highlight=button+beaniebots&page=2

post number 20

joe

 

[George Sephton]

Ive got it, my mums a genius in all this too:
http://www.all-electric.com/schematic/debounce.htm
See the first circuit and use it.
Then: Time = Capacitor value * Resistance
0.6 (seconds) = 0.000001 (10uf) * X (resistance appears)
The next picture shows the graph showing capacitance and how it all works.

Thanks.

 

[MFB]

General ripple counter tip

On the subject of driving simple ripple counters, it’s also worth remembering that their clock inputs require minimum rise/fall time for reliable operation. I was alerted to this when trying to drive a ripple counter directly from a rail-rail opamp. Although the opamp was configured as a comparator and gave nice bounce-free pulses, output slew rate limitations meant that the binary counter divided by different numbers depending on how hard the opamp was driven. All very puzzling until I looked at the counter specification in more detail!