Comments for FamiLAB

Comment on by Bruce Emerson

Bruce Emerson — Fri, 11 May 2012 23:51:23 +0000

I can’t wait to see what you all have been up to. I’m coming across the country from Oregon to learn from you about community maker spaces. I’ve been watching you and admiring your community from afar for a year or so. Looking forward to a great Mini Maker Faire!

Comment on Open House @ FamiLAB by Steven

Steven — Wed, 02 May 2012 02:58:28 +0000

Thanks for letting us come hang out and ask questions tonight! Looks like a perfect place to let my crazy ideas blossom. I can always use more tools, and instead of figuring out how to acquire said tools, I get get on with the project. Open house sold me!

Comment on Global Hackerspace Coopcake Challenge 2012 by Featured Project: TagBot: The Spray Paint Photo Booth | Orlando Mini Maker Faire

Wed, 25 Apr 2012 12:01:04 +0000

[...] and a cupcake (dessert) shipping container that looks like a cupcake (the Makerbot 3d Printer) for The Cupcake Challenge… [...]

Comment on Power Racing Fever at FamiLAB by Featured Project: TagBot: The Spray Paint Photo Booth | Orlando Mini Maker Faire

Wed, 25 Apr 2012 12:00:09 +0000

[...] If you’ve ever been to FamiLAB, you’ve very likely met John Bent Cope, or seen some of his work on display. He’s always making something creative, exploring the combinations of art and technology. (and sometimes he’s a Power Racing driver…) [...]

Comment on Dimmable AC Light Box by JDL

JDL — Fri, 06 Apr 2012 06:03:24 +0000

On additional thought, you can really factor out the asymmetrical aspect of the half wave detector. Whatever Vih is, the peak of the AC powerline waveform is going to be half way between the rising edge and the falling edge. Likewise the nadir of the low part of the cycle will be half way between the falling edge and the next rising edge.

This PIC has a timer. So if (after deglitching) you take the times of the rising and falling edges, you should be able to calculate where the peaks are, and thereby the zero crossings.

I’d probably set it up so that a timer caused an interrupt when it rolled over, intending that to be a zero crossing. Reloading the timer count should take into account the error based on the the expected peak times. If the peak is not at 1/4 of a cycle, and the low at 3/4 of a cycle, calculate the error, and add that in when setting the timer count back 1/2 a cycle in the interrupt service routine.

You can even use an initialization process at the start of day to figure out how many timer ticks a cycle is, and not worry about an absolute scaled time base. just get an average for a few cycles.

Therefore with a bitof deglitching, you should be able to know

Comment on Dimmable AC Light Box by JDL

JDL — Fri, 06 Apr 2012 03:54:35 +0000

I know this has been idle for a few months but just to give a possible solution.

You have a processor, which allows you more flexibility that a transistor circuit monitoring a full wave rectifier.

If you use a single separate diode as a half wave rectifier,with some resistors you’ll get a square wave at the line frequency, that you could read with logic input.

Now if life were perfect,you’d be set, because all you would have to do is monitor that input for an edge. Rising or falling. That would be a zero crossing. It may even work just that simple. But possibly there is line noise on the AC that would give you several as the signal is near Vinputhigh. There is also a symmetry issue, where voltage crossing would be different on one phase from the other. Its the kind of thing you’d use a Schmidt trigger to read if you were using pure logic.

This is where the processor comes in. You can calculate how deep into the wave form the input crosses Vih, and when it will crass back again on the way down. From there you can calculate where the real zero crossing is.

With further elaboration you should be able to use that data make a phase locked loop in software that locks into the 60 Hz signal of the AC line. Using that as a time base, then you can determine your triac firing times.

Comment on Power Racing Fever at FamiLAB by Mark

Mark — Fri, 06 Apr 2012 01:30:38 +0000

I can meet Tuesdays at 7 PM if anyone wants to work on the Power Racing cars. Let me know.

Comment on Thermo-Electric Axolotl Cooling by Bogwood???? - Caudata.org Newt and Salamander Forum

Bogwood???? - Caudata.org Newt and Salamander Forum — Wed, 08 Feb 2012 20:36:03 +0000

[...] not too warm for the axies. If it does start to get in the mid 20's then you could try this? Thermo-Electric Axolotl Cooling I think I will give something similar a go if we get a good [...]

Comment on Thermo-Electric Axolotl Cooling by Ways to keep tank cool!!! - Caudata.org Newt and Salamander Forum

Ways to keep tank cool!!! - Caudata.org Newt and Salamander Forum — Tue, 07 Feb 2012 00:16:00 +0000

[...] Re: Ways to keep tank cool!!! Hi, I was on stumble upon the other day and saw this. I am "lucky" enough to live somewhere cold enough so I don't need it but it may help you!? Thermo-Electric Axolotl Cooling [...]

Comment on Sunday Morning Code by digitalman2112

digitalman2112 — Sun, 05 Feb 2012 15:10:12 +0000

Haha, even on the calendar…nicely done