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1  Forum 2005-2010 (read only) / Interfacing / Re: Perf board layout software? on: August 08, 2007, 10:12:27 am
Thanks all.
Seems there's no REALLY good solution to this. My circuits are generally pretty simple, so I'll stick to dead-tree-and-graphite for now, I guess.

Although, if you've got a library of properly-sized components for AI, recur, I'd love to play with that.

S
2  Forum 2005-2010 (read only) / Interfacing / Re: Perf board layout software? on: August 07, 2007, 07:39:27 pm
Thanks.
I found a reference to "Stripboard Magic" which seems to be abandonware (can't buy it). I found a copy, and it does what I need it to do.. sort of.. the layout part isn't very smart, and it tries to outsmart you, which is annoying. Otherwise, it's not terrible.

S
3  Forum 2005-2010 (read only) / Interfacing / Perf board layout software? on: August 07, 2007, 02:24:34 pm
Hi,

I realize that this might not be the right forum for such a question, but I didn't see a better place. Feel free to scold me and/or move the topic if there's a better venue.

Does perf board layout software exist? A bit of googling turned up absolutely nothing. I know there's lots of PCB layout software, but I want to build some simple circuits on perf board, and I'd like to have some sort of blueprint for where things go (instead of working serially on the fly with my circuits). For example, I put a LED in backwards on my last perfboard layout, and had to move a component after I got my wits about me.

Should I stick to graph paper, or is there software that can help me turn a schematic into jumpered perf-board?

Thanks.

S
4  Forum 2005-2010 (read only) / Interfacing / Re: Polarity Reverser? on: August 10, 2007, 04:44:53 pm
Well, I picked up a TIP102 (clone, so the shop tells me) last week when I thought I'd have to drive this thing directly, so I'll use that for now, unless I can scrounge a 2N2222 from an old PCB or something (-;

Thanks so much for your help.

S
5  Forum 2005-2010 (read only) / Interfacing / Re: Polarity Reverser? on: August 10, 2007, 04:12:26 pm
Hi again,

Here's what I came up with for a circuit. Is it close? (don't want to fry my new arduino (-: )

ignore the LED.. pretend it's a relay (-:



S
6  Forum 2005-2010 (read only) / Interfacing / Re: Polarity Reverser? on: August 09, 2007, 01:50:07 pm
Thanks for the pointer in the right direction.
I don't need anything as complicated (or expensive) as an RC controller. I basically need forward and reverse. I don't really even need off (although I WOULD use it if I had it), and I certainly don't need speed control.

Would something like this do the trick? It looks cheap and easy enough:
http://www.mcmanis.com/chuck/Robotics/tutorial/h-bridge/bjt-circuit.html

S
7  Forum 2005-2010 (read only) / Interfacing / Polarity Reverser? on: August 09, 2007, 12:52:30 pm
Hi,

I'm back again with my amateur questions (-:

I'm going to be hooking up a peltier to my arduino through a power transistor (the peltier pulls 1.2A at 5v (!)).

As you may or may not know, a Peltier cools on one side and heats the other, creating a temperature difference between the two. I've got heat sinks and fans all worked out, etc. When the polarity is reversed, the heating and cooling sides are inversed, as well.

In the default configuration, the peltier will be a cooling device (cold on the inside of my cooling chamber, and hot on the outside). This part is relatively simple.

However, I'd like to be able to reverse the polarity of the peltier, electronically (by either lighting up a 2nd pin on the arduino, or by perhaps turning the pin off). I have no idea how to do this electronically. Is there a device that I've never heard of that does this? Would I need to use a dpdt relay or similar?

My power supply can deliver +5v and also +7v (+5v -> +12v).. not sure what 7v would do to the thermistor, but maybe I can buffer it with an appropriate resistor or something.

In any case... ideas?

S
8  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 09, 2007, 12:58:29 pm
Follow up to that project:

http://www.brewboard.com/index.php?showtopic=77935

Here's the output:
http://adnagaporp.caedmon.net:8000/keg.html

(teaser: )

Thanks again for your help.

S
9  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 07:02:32 pm
FWIW, I found another relay at Acces Electronique that was rated for 100A peak, but was supposed to trigger from 9-12VDC. I figured I'd hook it in with a transistor on the 9V line or something, but when I plugged 5v across the trigger contacts, it lit up, which is great. I reworked my breadboard into perf board, and now I have an over-functioning thermostat for my kegs. (-:

Turns out it wasn't the start relay, even though it seemed like it. I think that the other SSR was limiting the current enough to keep the compressor motor from spinning up, and that kicked out the overload protection part of the relay (as far as I can tell (-; ).

It's just a matter of time before I have the world's first web-enabled kegerator (-;

Thanks for all your help.

S
10  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 02:44:47 pm
Good to know (-:
Their relays are quite expensive, though. <shrug/>

Anyway, it turns out that the problem might not be with my SSR, but with the start relay on the compressor (I think, anyway...) I don't know anything about such things, unfortunately..

Friday afternoon fun, I guess (-:

S
11  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 02:00:23 pm
Home brew. (-:

I got the relay at Acces Electronique, yes, an Addison branch out here in the suburbs. I called Addison, directly, today to ask about SSRs, and they said they didn't have any (not that I really believe them, but it's a 30-min drive each way if they don't... )-: ).

Digikey can really deliver that quickly?

S
12  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 01:52:31 pm
Montreal (-:
this guy is just down the street from me, but he's not answering email.. )-:

(plus it's a bit expensive..)

S
13  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 01:44:29 pm
Ok; thanks. I'll take it back. Buying surplus sucks (-:

S
14  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 01:41:57 pm
Btw, I'm in Canada. I know I can mail-order or buy on eBay, but I was hoping to get my keggerator back up and running today...

S
15  Forum 2005-2010 (read only) / Interfacing / Re: High Volt, High Current Switching? on: August 03, 2007, 01:36:43 pm
Hi,

Thanks for the info.

A couple things, now.. (-:

First, I'm using the info above to power something else, now. 110v (which hurts much less (-; ), peak at 25A. The SSR I found works for this load, but it's the compressor of a freezer, so when it peaks out (unlocking the rotor), it draws enough power to drop the voltage of the SSR to ~80v, and then the freezer powers down for some amount of time. Perhaps there's a weird delay or something on the freezer side..

Anyway, the 2nd thing is that there's no short/load between 1&2 or 3&4. Just 20[ch937] between 3 and 2. Also, the 4th contact doesn't APPEAR to be broken off (there's no stub or anything; it's just missing.. like it was never there).

And a 3rd bit of info: there was a whole box of these at the shop. I guess it's possible they're all duds, but it doesn't seem that way. There must have been 50 of them.

S
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