The forum for discussing all kinds of brewing paraphernalia.
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Dr. Dextrin
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by Dr. Dextrin » Tue Jun 05, 2012 10:54 am
Brilliant! I spent most of my career in software and saw some interesting concoctions over the years, but I've never come across email software that also makes beer.
Still can't help thinking it'd be a bit of a pain waiting for the sun to come out before you can get the boil on!
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runthangs
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by runthangs » Fri Jul 13, 2012 12:40 pm
Hey guys,
I need some electronics advice. I have the triac circuit mentioned earlier that "dims" the power supplied to the heater, the dimming is controlled using an AC potentionmeter (model: wth118-1a).
I now need to programmatically control the potentiometer. Aside from getting an SSR and redoing the circuit, etc., I have explored using a servo motor controlled via USB to turn the pot, but have discovered that 5v/100ma from USB isn't strong enough for the motor to turn the knob (plus very inaccurate) - I want to avoid external power supplies etc. Is it possible to instead send a 5v current down a USB directly (via some conversion circuit of some sort) to one of the terminals of the potentiometer and thus vary the resistance (i'm looking for the simplest solution possible). I am happy with a binary "high power" and "low power", i.e. 5v and 0v from usb. This would allow me to at least step the potentiometer/dimmer circuit one level up when solar pv generation is high.
Thanks.
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themadhippy
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by themadhippy » Fri Jul 13, 2012 12:48 pm
Dont go there,the pot is at mains potential,connecting it to a usb port is likley to destroy the computer.An opto coupler triac to fire the existing triac would be a much safer option.
Warning: The Dutch Coffeeshops products may contain drugs. Drinks containing caffeine should be used with care and moderation
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themadhippy
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by themadhippy » Fri Jul 13, 2012 1:28 pm
Id start from scratch, something like

but instead of the printer port control the led via usb
Warning: The Dutch Coffeeshops products may contain drugs. Drinks containing caffeine should be used with care and moderation
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runthangs
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by runthangs » Fri Jul 13, 2012 2:26 pm
Your posted image is broken..
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themadhippy
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by themadhippy » Fri Jul 13, 2012 2:29 pm
Your posted image is broken
realy? showing here fine,i stole it from
http://www.laborki.cba.pl/gfx/discolitez2.gif
Warning: The Dutch Coffeeshops products may contain drugs. Drinks containing caffeine should be used with care and moderation
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runthangs
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by runthangs » Fri Jul 13, 2012 3:14 pm
ok, i see it now thanks. I am a software guy, rather than hardware (I have a soldering iron, but that hardly qualifies me

) so it's pretty daunting to do anything off schematics, hence the search for off-the-shelf solutions...
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Dr. Dextrin
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by Dr. Dextrin » Fri Jul 13, 2012 10:39 pm
Well if you want to use the stuff you already have, is the USB supply enough to turn the motor at all? If so, then possibly a reducing gear would let you turn the pot, plus make it more accurate. A mechanical connection should be safe enough, especially if you use plastic gears. Best steer clear of connecting anything electrical if you're not familiar with it.
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runthangs
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by runthangs » Sat Jul 14, 2012 1:02 am
I took the motor from a toy car, it turns fast with the 5v but not strong enough to turn the pot
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themadhippy
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by themadhippy » Sat Jul 14, 2012 1:33 pm
it turns fast with the 5v but not strong enough to turn the pot
gear it down to a few rpm,the torque will increase,and allow better control.Another alternative is a usb servo controler with the servo driving the pot
Warning: The Dutch Coffeeshops products may contain drugs. Drinks containing caffeine should be used with care and moderation
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andyCo
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by andyCo » Sun Jan 20, 2013 8:33 pm
Dr. Dextrin wrote:Just an update. I now have one of these power regulators and have tried it out in a lash-up fashion to boil about 10 litres of water using a 2.75 kW kettle element.
It comes with absolutely no instructions and the description on eBay is rubbish, but the device has just two terminals so I connected it in series with the load and it seems to do the job quite nicely. It varies the power smoothly from zero to max, and AFAICT there's very little power loss at the max setting
Just got one of these, Before I wire it up can I just check that I'm about to do it right, am I just splitting the live to my element through the controller ?
Thanks in advance
Andy
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jmc
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by jmc » Mon Jan 28, 2013 1:48 pm
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Dr. Dextrin
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by Dr. Dextrin » Mon Jan 28, 2013 2:00 pm
andyCo wrote:Dr. Dextrin wrote:Just an update. I now have one of these power regulators and have tried it out in a lash-up fashion to boil about 10 litres of water using a 2.75 kW kettle element.
It comes with absolutely no instructions and the description on eBay is rubbish, but the device has just two terminals so I connected it in series with the load and it seems to do the job quite nicely. It varies the power smoothly from zero to max, and AFAICT there's very little power loss at the max setting
Just got one of these, Before I wire it up can I just check that I'm about to do it right, am I just splitting the live to my element through the controller ?
Thanks in advance
Andy
Yes, that's basically it.
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Dr. Dextrin
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by Dr. Dextrin » Mon Jan 28, 2013 2:04 pm
jmc wrote:Can anyone spot any difference besides price?
TIA John
No. I can't see any signifcant difference, except that the components are set out slightly differently.