| eeka chu |
Okay, it's not strictly audio based...
But does anyone have any links to a circuit diagram for an LED based strobe?
I want to use the strobe for tuning musical instruments, so it needs to have quite a precise control over it's pulsing frequency.
I am totally at a loss when it comes to digital IC circuits! :) |
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| li_gangyi |
| so you wanna make a metronome huh?? A 555 with a pot to vary the frequency could do well enough for you...maybe u need super accuracy...then a PIC with a Crystal oscillator would do for you...with the PIC...set frequencies and timing can be selected using a few push switches...cool |
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| jackinnj |
| quote: | Originally posted by li_gangyi
so you wanna make a metronome huh?? A 555 with a pot to vary the frequency could do well enough for you...maybe u need super accuracy...then a PIC with a Crystal oscillator would do for you...with the PIC...set frequencies and timing can be selected using a few push switches...cool |
you can do it faster with a crystal AND discrete CMOS dividers. |
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| li_gangyi |
| ok...maybe I was a bit PIC crazy... |
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| eeka chu |
Well, something like a metronome I guess!
The pulsing frequency would need to range from about 50Hz to 2kHz.
Like I say... writing things like PIC chips is beyond me at the moment! :)
If I have a PIC chip writer, can I download flash programs and burn then to the chips, like an MP3 to an MP3 player?
How do the PIC things work? I mean, how does it physically make the circuit on the chip? Or does it just selectively destroy the bits it doesn't need?
Can you tell I have absolutely no idea what I'm talking about? :D |
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| pasan |
Hi Do u any good Strobe light with Two channel LED.
Like this
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| jackinnj |
| those are probably Luxeon emitters -- they take a special driver -- but this isn't a Herculean challenge. |
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| I_Forgot |
I've been working on a LED strobe project for a couple years now, on and off, mostly off. Mine allows precise control of frequency/period and on-time. It has an LCD display and drives a 5W luxeon LED.
Special drivers are not needed for Luxeon LEDs any more than they are needed for any other LED. My strobe fires 15A current spikes through the LED to get adequate brightness for microscope illumination with pulse durations as short as 5 us. The uC drives a low threshold MOSFET that switches the large current through the LED.
The controller uses a PIC uC plugged into a slightly modified off-the-shelf board with LCD display. I use timer1 in the uC with the capture/compare module to generate interrupts to fire the flash at accurately timed intervals.
The strobe tuners I have seen have a spinning disc with black and white pattern corresponding to specific notes. The firing of the lamp is driven by the audio signal from the instrument. Is this how you're planning to make the tuner? In that case you don't need a precision strobe, you need a precision motor speed control and patterned disc, and some sort of circuit to process the incoming audio from a mic to fire a lamp.
PICs are microcontrollers. They are fully reprogrammable, so you're not destroying any bits or creating any new circuits when you program them. Put simply, they get inputs from a variety of sources and process them to generate outputs as required. Inputs can come from external sources such as buttons or encoders, etc., or internal sources such as counters, timers, the master clock, etc. The processing can be as simple or as complex as you can imagine. You write a program that tells the uC which inputs you want to watch, and when, and what outputs you want to generate under what circumstances.
Yes, if you have either a PIC programmer or an appropriately set-up target board, you can DL programs from the web and burn them into the PIC like an mp3 file. However, programs for uCs are very dependent on the hardware (the circuit that the uC is part of), so unless you duplicate the hardware, the program from the web may not work in your circuit. You can disassemble such programs and see what techniques were used to achieve desired results but that is sort of an advanced technique. Most people who post code on the web post an explanation of how it works, so you don't have to disassemble the program to see what it does.
I_F |
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| jackinnj |
| the application I was performing required precise current control -- and some optical feedback to compensate for diminished output as the units heat up -- so I used some of the laser diode driver tools. |
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| jackinnj |
| quote: | Originally posted by eeka chu
I am totally at a loss when it comes to digital IC circuits! :) |
If you want to just get started you might want to try the Basic Stamp from www.parallax.com -- there is a huge group of users and a friendly bulletin board on the company's site.
you can then migrate your programs to the language which the Microchip processors use with a program called PicBasic. |
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