Dr.EM

Hi. Does anybody know of a counter circuit, or even better, a counter chip. What I mean is, a circuit that counts up according to clock input signals, ie, when 2 clock inputs are fed in, it lights 2 LEDs, OR better, displays 2 on a 7 segment. I can make one using 4 NAND gates and a dual JK flip flop, but that will only count up to four. I am ideally looking at one which will go up to 100, or possibly more. As you can imagine, 100 quad NAND and another 100 flip flops would be crazy. Also, the circuit needs to be able to deal with very fast clock signals (100khz+), but I doubt that will be a problem.

k7elp60

The CD14553 also known as the CD4553 is a 3 digit will count up beyond 1Mhz. I needs a display driver such as a 4511 or 4543 plus some digit driver transistors to run the 7 segment displays.

__________________
The great thing about electronics is unlimited ways to do the job. The only limit is one\'s imagination. I generally think my way is best.
Show me a different way. I have an open mind.

Russlk

A serial in - parallel out shift register, such as the 74xx164, can do the job. You would need 13 of these 8 bit registers to light 100 LEDs in sequence. The master reset will allow you to shut them all off and do it again.

__________________
see my website: www.geocities.com/russlk

jrz126

http://www.electro-tech-online.com/v...ic.php?t=12872

This what you are looking for? You can easily multiplex a couple of 7 segments displays to get more digits

__________________
Jeff Zimmerman
To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.

Dr.EM

Thanks for the help

I think that shift register sounds feesable. Perhaps i'll use a few less LEDs coming to think of it though, 100 might be expensive.

If you want to know there purpose of this, its going to be a speed counter, for measuring velocities. Basically, an oscillator (100khz+) is connected to the counter. There will be 2 barriers, the first will start the oscillator, and the second will stop it. Then the counter will display a figure via LEDs lit up. ie, 23. Then, using the distance between the barriers and this number, the velocity can be calculated. I expect real speed guns use a similar system, but this is for little things, not cars.

Nigel Goodwin

Real speed guns use doppler shift radar, although more modern ones use a laser rather than radio waves. There's no need for them to measure breaking beams.

But your idea is a very common one, there's lots of projects about for slot car racers for speed and lap timing.

It's a project done very easily using a PIC, giving a simple (and very cheap) one chip solution.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

Dr.EM

Ah, right.

I thought, there is another way to do this. that would be to have a counter that does only go up to 8, then to move the barriers closer until it displays 7 or so. Would take longer to measure, but would be easier to build.

Btw, although I would like to use some light gates, I will probably use gates made of tin foil, through which the objects will pass through. I know that slows them down, but it would be easier to build. Yeah, I am lazy...

chemelec

Look at the Up/Down Counter Circuit on my site.

http://www3.telus.net/chemelec/Projects/Projects.htm

It can be as little as one display or as many displays as you want.

__________________
I No Longer accept Private Messages on here.
All Emails to me Must Contain the Word \"Electronic\" in the \"Subject Line\"
or they go Directly to my Junk Mail Folder.
Email me at: chemelec@hotmail.com
Website: http://www3.telus.net/chemelec

Dr.EM

That does look perfect actually, how much does it usually cost (I can only construct on stripboard)?

See, I had another idea, which if I can get it to work will be very cheap and effective. Basically, I buy a £3.50 digital clock, and remove the internal oscillator and connect my own one up, assuming it can deal with considerably faster clock rate inputs. I know it'll count in 60s, but one without a second counter will count up to 760, and one with seconds up to 60 times that. So, what do you think? Can it use a 100khz osc instead of the 60hz one (big difference yeah, but digital stuff usually handles it). And, when the clock input stops, will it hold the figure, or reset to 0:00? And, a similar point, can you reset them?

Dr.EM

Ok, well, the chips used in chemelec's circuit I can't find at maplins, but they do sell a sort of all in one package that will count up to 19999, which has decoders, drivers etc onboard and works right up to 25mhz.

http://www.intersil.com/data/fn/fn3168.pdf

So, I can use either that, or the cheaper option of a clock, but I don't know for sure that that'll work.[/url]

__________________
Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

chemelec

The CD40110BE is Available from Digi-Key.
Part Number 296-3506-5-ND
They are a bit Cheaper than my price for this part, but if you only want one or two, My Postage cost is cheaper, Probably making it overall cheaper.

My Price is $2.00 Each, US Funds, Plus a Total Postage of $3.00.

Take care..........Gary

__________________
I No Longer accept Private Messages on here.
All Emails to me Must Contain the Word \"Electronic\" in the \"Subject Line\"
or they go Directly to my Junk Mail Folder.
Email me at: chemelec@hotmail.com
Website: http://www3.telus.net/chemelec