I want to flash an led at a variable rate, between 3 and 8 times per second, and think that a 555 timer might do the job but I have no real idea about designing a circuit myself, although I am quite capable of building it if someone could draw me a circuit, or tell me where such a circuit could be found. The on period needs to be only 10% of each cycle, but if this could be adjustable that could be a good thing, and need not be adjustable in use. If such a circuit is already on here please excuse me for not being able to find it. Regards to all, from Norris.
Variable speed flashing led
- Thread starter Norris
- Start date
Sounds like just using a variable resistor would work just fine. This would allow you to adjust the flash speed until it matches the lathe speed, kind of sync them together if I am understanding what you are trying to do correctly. I have to go out for a bit, I will check in here in a couple hours. This is very simple to do, I will draw up a schematic if you want when I get back.
George
George
Another option if you have some exact times you wanted to choose from would be to use a dip switch with each switch in the dip connected to a certain resistor that would create an exact time. Say the dip has 6 switches, sw 1 could be 1second, dip2 could be 2sec and so on. We could set this up to any indivigual times you want fo both on cycle and off cycle. I can put both these together and show via a video if you like. That would have to wait til the weekend though. be back in a bit.
George
George
I will have to play around with it and see. The problem with high speed flashing is that the light might appear to just stay on due to the time it takes to turn on and off. If we can't get 13.6 flashes per second we will get close I am sure. I have to go back out and will put this together and test the timming to see what we can get out of it before the led appears to just be on all the time. I will get back to you soon. I work nights so I have to sleep today at some point but will at least get a circuit put together and message you what I feel we can get as far as FPM before I do go to bed. Thank you for giving me a reason to tinker around with a project! 
George
George
VR1 and VR2 are both 10K Ohm variable resistors in the video. The resistance I have them set at to get approx 816 flashes per minute which equals 13.6 per second is VR1 = 360Ohms, VR2 = 1KOhm and the capacitor is a 47uF Electrolytic cap. I demonstrated a 5mm and 3mm LED in the video but that choice will be better determined by you. I went with the variable resistors so you can play around with the settings easier. If you would like to add the counter as seen in the video let me know and I will draw up the schematic for you as well as include a parts list.
If anyone has any ideas to make this better, more stable, or just sees something wrong with mine please post. I hope this helps you. This was fun for me!
George thank you very much for taking the time to do this for me, I will bookmark this page against the time when I can do something with it , at the moment I am running flat out, I have been busy all day finishing off a winch that we built for launching paragliders, we've used it with a great deal of success but now it is taking up room, so I've been tidying it up and now is on fleabay. Next I have to advertise my quadcopter on the same place, and then my FPV gear too!!!
I will build it, and will get back to you about its success or otherwise.
Oh, my mate said " You want to make a rotating workpiece held in a chuck rotating at 800 rpm look stationary? How long before you forget, and touch it??"
He has a point I suppose. I will put it on a push button so it switches off when not in use I think.
, at the moment I am running flat out, I have been busy all day finishing off a winch that we built for launching paragliders, we've used it with a great deal of success but now it is taking up room, so I've been tidying it up and now is on fleabay. Next I have to advertise my quadcopter on the same place, and then my FPV gear too!!!I will build it, and will get back to you about its success or otherwise.
Oh, my mate said " You want to make a rotating workpiece held in a chuck rotating at 800 rpm look stationary? How long before you forget, and touch it??"
He has a point I suppose. I will put it on a push button so it switches off when not in use I think.
George thank you very much for taking the time to do this for me, I will bookmark this page against the time when I can do something with it , at the moment I am running flat out, I have been busy all day finishing off a winch that we built for launching paragliders, we've used it with a great deal of success but now it is taking up room, so I've been tidying it up and now is on fleabay. Next I have to advertise my quadcopter on the same place, and then my FPV gear too!!!
I will build it, and will get back to you about its success or otherwise.
Oh, my mate said " You want to make a rotating workpiece held in a chuck rotating at 800 rpm look stationary? How long before you forget, and touch it??"
He has a point I suppose. I will put it on a push button so it switches off when not in use I think.
, at the moment I am running flat out, I have been busy all day finishing off a winch that we built for launching paragliders, we've used it with a great deal of success but now it is taking up room, so I've been tidying it up and now is on fleabay. Next I have to advertise my quadcopter on the same place, and then my FPV gear too!!!I will build it, and will get back to you about its success or otherwise.
Oh, my mate said " You want to make a rotating workpiece held in a chuck rotating at 800 rpm look stationary? How long before you forget, and touch it??"
He has a point I suppose. I will put it on a push button so it switches off when not in use I think.
George
Too much fuss is made over safety, I think we should remove all safety warnings and let nature sort things out .
But I do appreciate the concern.
I thought of synchronisation, but it would have to be triggered by the main shaft rotation and be adjustable to a degree so that the flash came at the right position. Not a lot of good flashing when the point I am interested in Os 180degrees out of phase :-(
. But I do appreciate the concern.
I thought of synchronisation, but it would have to be triggered by the main shaft rotation and be adjustable to a degree so that the flash came at the right position. Not a lot of good flashing when the point I am interested in Os 180degrees out of phase :-(
VR1 and VR2 are both 10K Ohm variable resistors in the video. The resistance I have them set at to get approx 816 flashes per minute which equals 13.6 per second is VR1 = 360Ohms, VR2 = 1KOhm and the capacitor is a 47uF Electrolytic cap. I demonstrated a 5mm and 3mm LED in the video but that choice will be better determined by you. I went with the variable resistors so you can play around with the settings easier. If you would like to add the counter as seen in the video let me know and I will draw up the schematic for you as well as include a parts list.
If anyone has any ideas to make this better, more stable, or just sees something wrong with mine please post. I hope this helps you. This was fun for me!
***I think I may have said something wrong in the video about on/off timming. R1 controls the time the light stays on, when R1 is increased the time the light stays on increases. R2 controls the time the light stays off, when R2 is increased the time the light stays on increases. I am sorry if I said that wrong in the video.***
I did this by using 2 555s. The first (astable) sets the speed of the blink. From 60hz down to maybe 5hz. I use a 200k 28-turn pot for R2. I'll look up R1 and C1 values later.
The second (monostable) sets the duration of the pulse. It's pretty low. Maybe 100µs. Barely enough time for the LED to fire.
The reason I set the pulse so fast is that I wanted that *stopped time* effect on fans and such. When I ran pin3 directly to the LED, the object would "blur" because the LED was on too long.
Anyway, 555-1 triggers the rate of blink and 555-2 triggers the led for 100µs.
Technically, 555-2 triggers an array of 2222 transistors which fire the LEDs. I wanted an array of 10 LEDs and I didn't think the 555 could handle driving all those.
The second (monostable) sets the duration of the pulse. It's pretty low. Maybe 100µs. Barely enough time for the LED to fire.
The reason I set the pulse so fast is that I wanted that *stopped time* effect on fans and such. When I ran pin3 directly to the LED, the object would "blur" because the LED was on too long.
Anyway, 555-1 triggers the rate of blink and 555-2 triggers the led for 100µs.
Technically, 555-2 triggers an array of 2222 transistors which fire the LEDs. I wanted an array of 10 LEDs and I didn't think the 555 could handle driving all those.
That sounds like the sort of thing I am trying to achieve XPTICAL, a circuit diagram would be great if you have the time. I had to bore into a block last week, and it had a recess in the side which meant that the cutting tool was exposed as the work revolved. As the tool was quite shiny I was able to shine a bright but narrow beam of light in the right place and as the gap rotated past the light the tool lit up, as it were and gave me an effect similar to what I am after, which was quite encouraging to me.
Oh, I have no facilities for making a circuit board so I have to use veroboard :-(
Oh, I have no facilities for making a circuit board so I have to use veroboard :-(
Veroboard is excellent anyway.
I've just spent all day making a 555 astable mated to a 555 monostable (on veroboard ) to get a decent strobe effect.
The secret is to decouple the two circuits so that when the monostable switches off it doesn't 'see' the end of the astable pulse and stay on, so you put a 100nf capacitor between the two circuits and a 10k resistor up to the power rail to make it switch off.
I tried earlier to upload the diagram to photobucket but it would not work
I'll try again tomorrow, I think they were having problems
Rich
I've just spent all day making a 555 astable mated to a 555 monostable (on veroboard ) to get a decent strobe effect.
The secret is to decouple the two circuits so that when the monostable switches off it doesn't 'see' the end of the astable pulse and stay on, so you put a 100nf capacitor between the two circuits and a 10k resistor up to the power rail to make it switch off.
I tried earlier to upload the diagram to photobucket but it would not work
I'll try again tomorrow, I think they were having problems
Rich
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It works best looking at a fan blade when it's been switched off and slowing down, so the slower the lathe speed the better.
I think it would be great looking at streaming water but my taps don't create the right kind of water beads, disco lights would be AWSOME ! I switched off all the lights in the room and it really makes a great effect, like your moving in slow motion
Rich
I think it would be great looking at streaming water but my taps don't create the right kind of water beads, disco lights would be AWSOME ! I switched off all the lights in the room and it really makes a great effect, like your moving in slow motion
Rich
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