Computer Science Canada

need help with building a circuit
Author:  ecookman [ Sun Nov 22, 2009 9:31 pm ]
Post subject:  need help with building a circuit
I am going to try to build "The Time Fountain" (google that to understand) and i am wondering if anyone has attempted this, and if they have any recommendations on how to do it. Also I have built a 555 timer running LED's (they are strobing) but will the strobing be fast enough?

If not where can I find a circuit that I could made LED's strobe at faster speeds?
Author:  jernst [ Wed Nov 25, 2009 7:35 pm ]
Post subject:  Re: need help with building a circuit
I googled the time fountain thing you are talking about, but in my quick search couldn't find any information on how fast it needs to oscillate to achieve the effect you want. You should be able to control how fast the 555 timer oscillates by the capacitors/resistors you use in conjunction with it. I'm not sure if there is a certain range of values the 555 timer is capable of since I don't have much in the way of an electronics background (maybe someone else could comment). This page might help you a bit, it shows how you can control the rate of the 555 timer towards the bottom of the page: http://www.doctronics.co.uk/555.htm
Author:  ecookman [ Wed Nov 25, 2009 8:35 pm ]
Post subject:  RE:need help with building a circuit
ooh, thanks thats very helpful.
Author:  apomb [ Fri Nov 27, 2009 9:17 am ]
Post subject:  RE:need help with building a circuit
you'll want to adjust your duty cycle, and not just the frequency. If you want to show just one droplet of water, you need a duty cycle in the range of 20% ON (the site jernst showed shows the calculations for setting your duty cycle). If you want to show a few drops within one pulse, you need a duty cycle more in the 60% ON range. This gave me an idea as well, and since work has been slow, and I have a breadboard and my electronics kit, im going to build myself a visual metronome.

EDIT: echoman: you can also adjust your water flow rate accordingly Wink

EDIT2: just built my own flasher and it seems to go pretty fast (~60khz) which should be plenty
Author:  ecookman [ Fri Nov 27, 2009 3:13 pm ]
Post subject:  Re: RE:need help with building a circuit
apomb @ Fri Nov 27, 2009 9:17 am wrote:
you'll want to adjust your duty cycle, and not just the frequency. If you want to show just one droplet of water, you need a duty cycle in the range of 20% ON (the site jernst showed shows the calculations for setting your duty cycle). If you want to show a few drops within one pulse, you need a duty cycle more in the 60% ON range. This gave me an idea as well, and since work has been slow, and I have a breadboard and my electronics kit, im going to build myself a visual metronome.

EDIT: echoman: you can also adjust your water flow rate accordingly Wink

EDIT2: just built my own flasher and it seems to go pretty fast (~60khz) which should be plenty


alright, i finally got the frequency to be at a really high rate using a variable resistor, and a 1micro ferr. capacitor, I havn't gotten a chance to look over the website, but i digress...the LED I was using burnt out even thought I had a 220 ohm resistor with it, would and can flashing LEDs at fast speeds cause them to burn out? (I'm going to read over that web page later on tonight, if it is mentioned there plese say so so I DON'T MISS IT Razz thanks for the help sofar.

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