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Basic Electronics » I need help finding a terminal.

November 19, 2013
by Pew446
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Hey! I'm building a Christmas Light Synchronizer again, I've remade the board from last year and I'm having trouble fitting the board in the enclosure I want. I found this enclosure on Amazon, and my board should fit inside, except for the height.

I wanted to use these binding posts with these banana jacks, but they add up to be 2.77 inches, which is above the 2.2 inches depth of the enclosure. Normally I'd just stick a wire inside the binding posts, tighten it down and call it a day, but these posts have no holes in them, so the wires fall out pretty easily (I had this problem last year.) The posts would be carrying 120V and around 0.6A.

Here is an image of my circuit. The squares next to the holes for the binding posts are for soldering down that tab you see in the product image.

Does anyone have any suggestions on what I could use to hold down my wires? I have thought about simply soldering the wires in, but I'd like them to be removable easily in case I need to open the enclosure. I have also thought about using RCA jacks, but I can't find a voltage/current rating on them and don't know how well they would handle 120v/0.6A. I plan on having the outlets on the lid of the enclosure and the board on the base of the enclosure.

Lemme know what you guys think. Thanks! (If something doesn't make sense, let me know.)

November 20, 2013
by Rick_S
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Why not use These. If you haven't already made your boards up, it would require little modification to just place one of these at each triac output and then use electrical cord pigtails to go from your board to light strings.

This is how many of the light controllers do it. I built one of These Renard 16SS boards a coulple of years ago, and other than testing it with Vixen, never did anything with it. Who knows, maybe this year :D

Rick

November 20, 2013
by Pew446
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That looks like what I'll do, thanks Rick! I encourage you to set up a little light show this year, they are a lot of fun!

November 20, 2013
by Pew446
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I played with the board a lot, reorganized the wires, added space for heat-sinks on the triacs, and added in the screw terminals. Here is what it looks like now if anyone was curious. (I'd post the image here, but it's enormous.)

So, I will be going with the screw terminals. Thanks!

November 20, 2013
by JKITSON
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Rick

Thanks for the info on the Renard 16SS boards. This is a project I would like to do also. You just saved me a lot of time...

Jim Kitson

November 21, 2013
by Rick_S
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That's not exactly what I had in mind for the screw terminals. My thoughts would be to add a neutral terminal to your power input block and on each output block. You would then have one side neutral and the other hot thus making the power connections simpler. This would allow you to get eight cheap extension cords, cut off the female side leaving a foot of wire or so, then just attach the two wires to each terminal block for each output. Then use one of the male ends to attach to the power input (Both neutral and hot). It would eliminate bunching all the neutrals together separately. It wouldn't be a bad idea to add a fuse to the power input side as well, just to keep things safe in the event of a short.

November 21, 2013
by Pew446
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That's a good idea, I am actually using outlets that I will mount to an enclosure instead of extension cords, so I was planning on just wiring the neutral line straight to the outlet, but I guess it wouldn't hurt to add a neutral line to the terminals, too. I have thought about adding a fuse, but I'm not sure how big I should make it. Would 5A be reasonable? (0.6A per channel, enough for 2 100-led strands per channel.) Thanks!

November 21, 2013
by BobaMosfet
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Pew446,

5A is reasonable, go for 250V if you can.

BM

November 21, 2013
by Pew446
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Here I added in the fuse and the neutral line. Neutral is the round pad of the terminal (The one not connected to the fuse.) I am using this fuse holder with this fuse, which has no voltage rating posted, but I assume it is 250V since the ones which do have voltage rating are at 250V. I'll contact Tayda for more clarification. I'm using 10A because that's what they use on the Renard 16SS schematic.

Also, I have another question, I am using V-USB to control the lights, and on the 3.6V Zener Diodes which limit the data lines to about 3.3V, people are using 1/4 or 1/2W diodes, while Tayda only carries 1W diodes. Will this affect the circuit? I've seen a post saying that 1W diodes won't work, but I'd like confirmation before I order something that won't work. Thanks for the help!!

November 21, 2013
by Pew446
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Nevermind, I answered my own question reading the hardware page on the V-USB wiki: "We recommend 3.6 V low power types, those that look like 1N4148 (usually 500 mW or less). Low power types are required because they have less capacitance and thus cause less distortion on the data lines."

I'll just order them on DigiKey, no problem.

November 22, 2013
by Rick_S
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Looks like it'll be a nice little board, with V-USB, is it coming up like a serial connection on the PC?

November 22, 2013
by BobaMosfet
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Pew446--

A 1N4148 is not a zener, it's a signal diode. A 1N4728 is a 3.3V Zener. You only need 1 zener, and 1 resistor to drop your voltage (we'll assume 70mA at 3.3V). A 43-Ohm, 0.5W resistor will do what you need.

Put the resistor in series on the hot leg coming off the USB, and then drop your zener across the hot and ground coming off the USB. Remember to connect it backwards (cathode towards positive rail.

What exactly are you using the 150-Ohm resistors for? Not to control the 120VAC Mains down to .8A, I hope...?

BM

November 22, 2013
by BobaMosfet
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Pew446--

I just realized what you were trying to do-- ignore my post above regarding the zener and the resistor. I blame it on the flu.

BM

November 22, 2013
by Pew446
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Rick, that is the plan. I found a library called AVR-CDC which implements V-USB and creates a virtual COM port.

Boba, did you forget your flu shot? C'mon now.. :P

November 23, 2013
by BobaMosfet
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Pew446--

Didn't get one, should have. Inlaws visited, and brought a bug with them. My head feels three feet thick, and I wish I could remove the cheese-grater from my throat.

BM

November 25, 2013
by Pew446
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So, I'm actually on a tight schedule for this board, (My high school is decorating the hallways with xmas lights and want me to synchronize them.) so I am going to actually just buy this USB to TTL adapter and play with V-USB another time. As much fun as it is to take risks, I want to deliver a working board. After all, I'm not paying for the parts, the school is. I need all the parts by Monday or Tuesday next week, so here's to hoping! I'll post later, probably next week, on the results. Thanks for all the help!

November 26, 2013
by Rick_S
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That's probably the safer way to go, I would anticipate that the USB emulation would take up quite a bit of overhead in the mcu, not to mention, according to the link you provided, you have to patch the windows serial driver to make it work.

The USB-serial adapter will most likely be a much simpler implementation.

Good luck with your display, you'll have to show us the final board and video of it in action!!

Rick

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