Screw Switch Awesomeness!!!

warnerr said:

suggest you check out eggtimers wifi switches and their quark altimeter that included wifi controls. I cant go back to using switches- i am so happy with these products. gGreat flights yesterday- and everything safely activated by my phone with charge status displayed.

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I just built my first WiFi Switch and Quantum, and I agree- makes arming and configuration (for the Quantum) a breeze. One thing I've mentally been chewing on, and would like your input (not to hijack the thread, but it's related to swtiches) is about redundancy- using two different devices (different manufacturer) would be, in my estimation, the most secure. So, if I'm using my Quantum, I might stick an RRC in there too, which requires a switch, which negates the wireless benefits of the quantum. Two "Quanta", however unlikely, may both suffer a failure related to design or assembly. Would it be wise, then, to include the Quantum, and a WiFi Switch on the RRC, or is that not isolated enough from a design standpoint?

In this day and age the business about using two different products is a fallacy and stupid. Many devices have an Apogee delay and can set a different deployment altitude say 200 feet lower than than the main deployment device. If one is so worried about the reliability of a particular device, "They shouldn't be using one in the first place."

Got two of one kind of altimeter? Fly 'em both on the same project for crying out loud keeping in mind the Mach delay (if they need those set) and appropriately set the apogee and main.

In the grand olden days before apogee delays could be set, it was unlikely that they would blow at the same exact time even if they were of the same make.

The only problem I'd foresee is if one were dim-witted enough to run both devices off the same battery! Then I'd think that would be more of an issue not that they are of the same make.

Kurt

I use two independent systems: quantum and a wifi switch activating a raven. dual everything- battery's, charge wells, etc. my rockets are carbon fiber and the sled is machined aluminum. Signal was good over 100 ft away. twos separate armings. I have a lot invested so reliability is #1.

For most flights and most rockets, devices from one company should be just fine; but, I must agree with warnerr that for the ultimate in reliability, it is best to have redundant systems of different types.

Both software and hardware are complicated systems. Design faults do happen, and they can cause identical redundant systems to fail at the same time. That said, it's a numbers game. If an altimeter fails once in 100 flights ( randomly ), and fails due to a design fault ( and very specific conditions ) once in 10000 flights, using two redundantly leaves you with, roughly, the same failure probability from random events -- one in 10000 . Overall it is a big win. Any product that has a design fault as likely to happen as a random fault isn't likely to have very good reviews -- the faults would be found quickly. Besides, there are plenty of other -- more likely -- sources of error: connectors, ignition charges, mechanical binding, etc.

Martin Jay McKee

This topic is on screw switches. Please stay on topic. If you want argue wifi switches, start another thread.

I do think screw vs. remote is a valid discussion point Chuck even if it's occurring here. For some projects switches are fine and dandy with being the only game in town for many years. I think the reliability discussion will help folks too. Kurt

The key concept is are you willing and to pay $20 for a wifi switch when a 59 cent piece of wire or a 3$ switch will work.

cwbullet said:

The key concept is are you willing and to pay $20 for a wifi switch when a 59 cent piece of wire or a 3$ switch will work.

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Or $25.00 for a magnetic switch. On the other hand $40.00 for a dual deploy device that's small enough to be buried in an airframe with remote activation and downloading on a commonly available appliance is a mighty fine advancement.

It's just a small short step from there for a remote device specifically for activating/arming staging or airstart electronics from a safe distance away. That's what I find very exciting as it lowers the prospect of an unfortunate ground event.
I apologize for being OT, but again this will put "unproven" shunts in the dustbin of antiquity where they belong.

I found the pictures in this thread very informative as to how to use doohickies and doodads to keep from mashing and wrecking one's deployment device with an errant screwdriver tip when trying to activate a screw switch. Pretty nice improvisation.
Kurt

Found this old post I put on TRF showing how to build your own screw switch:

https://www.rocketryforum.com/showthread.php?121577-Screw-Switches&p=1405705#post1405705

I have 3 unsused Featherweight screw switches. . I thought i was going to finally use them on my DS3 sled and was able to fit a pair of schruter switches on instead.

I will use tje screw switches on my Red Alert night launch rocket or my Class1 NytFlyr Payload.

My last sled was dual Quantums on a 3 inch Shredder.

Kenny

hognutz63 said:

At least in my eyes. My 12 year old daughter's look of indifference said otherwise. However I thought I'd share. I have used Featherweight screw switches in the past and either glued them to the inside of the av-bay coupler or mounted them to the backside of the sled. In the first method I always was worried about stresses on the wires from one end of the wires being stationary.

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What is the worry, that the sled and avbay body vibrate separately from each other and thus damage the wires?

I could see that but it seems unlikely in the lifespan of most rockets.

watermelonman said:

What is the worry, that the sled and avbay body vibrate separately from each other and thus damage the wires?

I could see that but it seems unlikely in the lifespan of most rockets.

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No, just fatigue from installing and removing sled from the av-bay when the switches are mounted permanently to the coupler.

hognutz63 said:

No, just fatigue from installing and removing sled from the av-bay when the switches are mounted permanently to the coupler.

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Oh! I could see that being an issue.

I've been thinking about making these screwdriver guides for Missile Work's screw switches for a while. They are roughly 1/2" x 3/8" x 1". The hole for the screwdriver is 3/16". It's sized for a Wiha #1 screwdriver. I also made a version with a .280" hole for a #2 screwdriver. The nice thing about this smaller one is that I pocketed the backside so the screw is captured and cannot fall out.

ChrisAttebery said:

I've been thinking about making these screwdriver guides for Missile Work's screw switches for a while. They are roughly 1/2" x 3/8" x 1". The hole for the screwdriver is 3/16". It's sized for a Wiha #1 screwdriver. I also made a version with a .280" hole for a #2 screwdriver. The nice thing about this smaller one is that I pocketed the backside so the screw is captured and cannot fall out.

View attachment 289658

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Put me down for a dozen!!

ChrisAttebery said:

I've been thinking about making these screwdriver guides for Missile Work's screw switches for a while. They are roughly 1/2" x 3/8" x 1". The hole for the screwdriver is 3/16". It's sized for a Wiha #1 screwdriver. I also made a version with a .280" hole for a #2 screwdriver. The nice thing about this smaller one is that I pocketed the backside so the screw is captured and cannot fall out.

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excellent design, especially the part about the pocket for retaining the screw. Can the terminal blocks still be used if needed/desired?

ChrisAttebery said:

I've been thinking about making these screwdriver guides for Missile Work's screw switches for a while. They are roughly 1/2" x 3/8" x 1". The hole for the screwdriver is 3/16". It's sized for a Wiha #1 screwdriver. I also made a version with a .280" hole for a #2 screwdriver. The nice thing about this smaller one is that I pocketed the backside so the screw is captured and cannot fall out.

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What are they made out of?

rharshberger said:

excellent design, especially the part about the pocket for retaining the screw. Can the terminal blocks still be used if needed/desired?

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Thank you. I'm not sure if the terminal block will fit with the current design. I might need to make it a little bit shorter.

timbucktoo said:

What are they made out of?

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They're made out of Delrin.

I will take 6

ChrisAttebery said:

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Those are real nice. I can see an order soon. I might have to wait for my tax return.

I've started a thread for my guides in the vendor's area. Please keep discussion of my guides there and let this thread go back to general discussion. Thanks!

https://www.rocketryforum.com/showthread.php?133816-APE-Screwdriver-guides-for-Missile-Works-screw-switches