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Old 11th Jun 2019, 7:11 pm   #97
David G4EBT
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Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,761
Default Re: Turntable Stroboscope

Quote:
Originally Posted by Radio Wrangler View Post
I just gave a couple of gentle suggestions. I think Tony did the heavy lifting on the design, and the finished production version by G4EBT is rather professional. Stick your three names on it and bung it in PW!

David
Thanks for the kind comments David.

As to PW, many years ago former Editor Rob Mannion changed the editorial policy to be exclusively about ham radio and that's the readership base it caters for. The eclectic range of practical constructional articles of yesteryear has long gone. ('Texan' amplifier, 'Wimborne' Music centre, Metal detectors, 'Robin' frequency counter etc etc). Since they discontinued Tony Nailor's excellent long-running series 'Doing it by Design' (which ran from 2004) and 'Technical for the Terrified' (ran from 2005), there's been little practical content of any kind, or so it seems to me.

The strobe is probably a bit too 'off topic' for the BVWS Bulletin too I think.

A few more pics below:

Pic 1: The 4.91520 Mhz square(ish!) wave output from the crystal oscillator to the input of the 74HC4060.
Pic 2: 300Hz square wave output from the 74HC4060.
Pic 3: The asymmetric output from the transistor driver to the LED.
Pic 4: Inside view of the prototype PCB, since modified and reduced in size as shown in my earlier post to remove the protection diode on the 9V input and to fit a 100mA 78L05 regulator rather than a 1 Amp 7805.
Pic 5: ready for the lid to go on the box.

The total consumption is only 8.5mA, due in part to the LED being on for only 6.25% of each cycle, and off for 93.75%, albeit to the human eye it appears to be a bright (ultra-bright!) continuous white light. Incidentally, I'm not sure what term would describe the current drawn by the LED - 'intermittent' DC, 'chopped' DC or what?!

I'll now need to print off a strobe disc to try out the strobe.
Attached Thumbnails
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Name:	4.91520 MHz Waveform at pin 8 xtal osc.jpg
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Name:	300Hz output from 74HC4060.jpg
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Name:	Output to LED.jpg
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Name:	Boxed strobe pic 1.jpg
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Name:	Boxed strobe pic 2.jpg
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ID:	184910  

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