What is this forum terminal block craze for?

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Andrew_ASC

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I just got some Aerocon PCB switches. I planned on soldering insulated wires to its pins then heat shrink or potting epoxy over the each connection. Then drilling hole in the Av bay switch band on the coupler tube. Then epoxy the PCB switches into the band holes. Then wiring those wires into the terminal blocks already on the altimeters switch input/output from the PCB switch. I plan on using like a foot of wire per connector to allow room to remove av bay tray and hook up batteries etc that way. Then drilling holes into the lid bulkhead of the av bay for the ejection wires to run too. Then putting separate altimeter port sizing holes for pressure sampling on the av bay band. Then sealing off the holes in the lid with like electric tape or putty. And using terminal block on altimeter already for apogee and main charges.

I am new to dual deploy but I don’t understand why someone needs a terminal block not already on the altimeter itself???? Can somebody explain. If anybody thinks I got bad ideas forgoing more terminal blocks not already on the altimeters please advise.
 

richP

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I think the terminal blocks you are referring to are used for ejection charges. You put a block on the outside of the AVbay bulkhead, so that you could have permanent connections to the altimeter side, and temporary connections to the e-matches.

Other than that, the only reason I could see using additional blocks inside of the AV bay would be to enable easy removal of altimeters; so that they can be used in multiple rockets.
 

g.pitts

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You may as well have asked opinions about something less polarizing, such as politics or religion.

Seriously, you’re going to get a lot of divergent opinions based on the balance of ease of wiring and risk reduction.

Connectors are the least reliable part of an electronic system. They can wear out, they can separate due to vibration, etc. So your intuition around NOT adding more connectors in the form of terminal blocks is good. The more connectors, the higher the probability of having a connector-related failure. They do have their place as I mentioned, one being ease of removal of a failed component from your electronics bay.

Here’s my plan for my electronics bay (hope to have photos within a couple of weeks): I plan to solder power, ground, and charge output wiring directly into my Eggtimer Quantum altimeters. Those wires are going into JST automotive grade connectors (not the red connectors that everyone calls a JST connector) that will plug into a simple PCB I designed and had fabricated. For the altimeters’ charge wiring, it is routed to a two piece terminal block from Phoenix (they make great terminal block systems) at either end of the PCB, where it then transitions to discrete wires that go through the bulkheads and into the white nylon terminal blocks for the igniter wiring. That’s a lot of points of failure some may say, but the selection of connectors was careful and intentional, and based on what I’ve successfully used in past designs.

I believe you’re thinking it through and asking good questions. Minimizing connector systems will minimize your probability of a connector-related failure.

Now about your switches. A PE I worked for eons ago hammered into me that a reliable solder connection should be both a mechanical bond AND a metallurgical bond. I’ve seen people place two wires adjacent to one another and place a bit of solder between them. This will fail because it lacks any sort of mechanical bond. Wrapping the two wires together and then soldering them satisfies both requirements. To that end, be sure you have one or more wraps of the wire around your switch pins (I assume these are through-hole pins intended for PCB mounting?) and then solder them. You’ll have a higher probability of yielding a reliable connection that will tolerate the shock and vibration it will no doubt experience.

Hope this helps!
 
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rharshberger

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I use terminal blocks on my altimeters only and purchase ematches with 1m leads then wire them directly to the alt using pass through holes on the bulkhead plugged by either poster tack adhesive putty or with rubber expansion nuts aka well nuts. A few of my altimeters I have set up with wire wrap posts for the ematch wires (if wire wrap was good enough for Apollo its good enough for model rocketry) the only connector is a JST-RCY between the Quantum/Quark and the battery which is zip tied on each side of the connector to the sled so it cant become disconnected.
Wire wrapping is a superb form of connection both electrically and mechanically, done properly it also prevents oxidation at the connection points.
 

g.pitts

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I use terminal blocks on my altimeters only and purchase ematches with 1m leads then wire them directly to the alt using pass through holes on the bulkhead plugged by either poster tack adhesive putty or with rubber expansion nuts aka well nuts. A few of my altimeters I have set up with wire wrap posts for the ematch wires (if wire wrap was good enough for Apollo its good enough for model rocketry) the only connector is a JST-RCY between the Quantum/Quark and the battery which is zip tied on each side of the connector to the sled so it cant become disconnected.
Wire wrapping is a superb form of connection both electrically and mechanically, done properly it also prevents oxidation at the connection points.
I grew up using wire wrap for prototypes. If I recall correctly, gold plated pins were most often used and the commonly used wire was 30 gauge silver. As you mentioned, the contact points between the silver wire and the four corners of the gold pins became a gas-tight seal. What a brilliant and relatively simple system!
 

Bat-mite

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Like anything, a tool is only useful when you have a use for it. If you've built your AV bay and didn't find a need to quickly connect/disconnect any wires, then you don't need anything else.

Some people use a long e-match shoved through a hole in the bulkhead and attached directly to the alt. Others (like me) use qucik-connects and terminal blocks.

https://en.wikipedia.org/wiki/High-power_rocketry#/media/File:Av-bay.jpg
 

wsume99

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I use terminal blocks on my altimeters only and purchase ematches with 1m leads then wire them directly to the alt using pass through holes on the bulkhead plugged by either poster tack adhesive putty or with rubber expansion nuts aka well nuts. A few of my altimeters I have set up with wire wrap posts for the ematch wires (if wire wrap was good enough for Apollo its good enough for model rocketry) the only connector is a JST-RCY between the Quantum/Quark and the battery which is zip tied on each side of the connector to the sled so it cant become disconnected.
Wire wrapping is a superb form of connection both electrically and mechanically, done properly it also prevents oxidation at the connection points.
Would you mind sharing more about where you sourced the posts from that you are using for wire wraps? Are you just using 0.1" pitch header pins?
 

Handeman

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I've been running wires from terminal blocks on the end caps of the av-bay to the altimeters. The ematches connect to the terminal blocks. That way I don't have open the av-bay to connect ematches.

My latest av-bay used these terminal blocks. I drilled two hole and cut a slot. Mounted the terminal block and then used rtv to seal the block to the end cap.
terminal strip.png


end cap.png


The wires are soldered to the terminal block tabs and covered in heat shrink.
end cap wired.png


The av-bay is wired with white/green from main charge and yellow/green drogue charge to the primary altimeter.
The white/blue main and yellow/blue drogue to the secondary altimeter.
Av-Bay.png
 

Scrapmaster87

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That's either brilliant or horrible. I'm just not sure yet.........
I wrap the e-match lead around the stainless loop to minimize the stress. Got 2 flights back to back in February with zero issues. This was my test for a rapid turnaround with dual deploy. I think I managed to turn it around in maybe 10-15 minutes with pre-loaded motor(s) and charges. You can see the 1/4-turn locking lugs and locking detent below in the picture.

I give the the terminals a quick squirt of grease to make sure the contacts stay clean. When I opened it up for the picture, I thought it was half melted, but it looks almost new!
 

SDramstad

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I wrap the e-match lead around the stainless loop to minimize the stress. Got 2 flights back to back in February with zero issues. This was my test for a rapid turnaround with dual deploy. I think I managed to turn it around in maybe 10-15 minutes with pre-loaded motor(s) and charges. You can see the 1/4-turn locking lugs and locking detent below in the picture.

I give the the terminals a quick squirt of grease to make sure the contacts stay clean. When I opened it up for the picture, I thought it was half melted, but it looks almost new!
I would probably wrap it in masking tape after the e-matches are connected. Where did you get them?
 
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