# Switches - lets talk - for altimeters & electrocnics

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#### dr wogz

##### Fly caster
OK, so we have those rotary switches (typically labeled 110v / 220v)
We have those screw switches which is a screw mounted to a PCB
We have various methods of the typical slider switch, with various ways to pull/push on/off (and a new start-up who has some lovely 3D printed sleds)
Magnetic switches.. (And a magnet you keep in your pocket all day, then realize your hotel room key has just been wiped..)
key switches, which can be big & bulky
and the old wires thru a vent hole & twisted together.

Preferences? Sources? Pitfalls? Mountings?

some back story:
I'm a recent L2,and am getting into all this "Dual deploy" and other fun electronics we have in our hobby. (read: learning a lot!!) Are there preferences? Are there likes & dislikes?

I am a fan of simplicity, and have done the twisted wires thru a vent hole, with a bit of tape to ensure they stay twisted. A good friend, also a rocketeer, prefers a proper switch & other gadgets. (and, to be honest, I think we all think highly of someone who has all the 'remove before flight' tags hanging off a rocket (or plane..))

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#### timbucktoo

##### Well-Known Member
Staff member
TRF Supporter
Global Mod
Eggtimer wifi switches are convenient. No ladder required for those hard to reach altimeters. Any smart phone will work. Only down side is wifi is a battery hog so you need at least 500 mAh Lipo.

#### cwbullet

##### Obsessed with Rocketry
Staff member
Global Mod
I am writing an article on different switch options and would love to see more options: Subscribed.

#### dr wogz

##### Fly caster
The Eggtimer Wi-Fi Switches, are they NAR / TRA certified? I remember (vaguely) reading about the fact they needed to be a physical on/off.. and I might be thinking about their Wi-Fi Quantum arming..

#### Steve Shannon

##### Well-Known Member
TRF Supporter
The Eggtimer Wi-Fi Switches, are they NAR / TRA certified? I remember (vaguely) reading about the fact they needed to be a physical on/off.. and I might be thinking about their Wi-Fi Quantum arming..
The EggTimer WiFi switch was specifically approved for use by the Tripoli BoD at LDRS 36. Points we took into consideration included the fact that it boots with its outputs in the off state and that two solid state devices must be switched in order for current to flow.

#### Wallace

##### Well-Known Member
TRF Supporter
The EggTimer WiFi switch was specifically approved for use by the Tripoli BoD at LDRS 36. Points we took into consideration included the fact that it boots with its outputs in the off state and that two solid state devices must be switched in order for current to flow.
Outstanding. Does this "ruling" also apply to the Quantum?

TRF Supporter

#### Bat-mite

##### Rocketeer in MD
Plastic 110/220 switches: pro: work well, small drill hole, screw driver operable. con: break easily from normal use.

Metal DigiKey key switches: pro: won't break, work well. con: inflexible/hard to tighten, larger top profile, key required (nothing like walking a mile to your bird and having to listen to the beeps all the way back because the key is on your table)

Screw switches: pro: very simple, work well, won't break, 0 external profile. con: have to stick a long screwdriver into a vent hole where you can't see (saw a friend spend 10 minutes trying to get the blade in the slot in a 7.5" airframe).

Magnetic switch: pro: work well, no external profile, won't break. con: can be hard to locate switch (i.e., spend lots of time waving the magnet all over the place). See above about forgetting the magnet.

#### AlphaHybrids

##### Well-Known Member
Since screw switches came out - Featherweight and Missileworks - that is all I use or recommend. They are rock solid. The Missileworks ones now come with a guide to help locate the switch. After being at the Spaceport America Cup and seeing every single manifestation of a switch implemented, it solidified my commitment to screw switches. Just an FYI, I didn't see any screw switches at the Spaceport.

Edward

#### markkoelsch

##### Well-Known Member
Since screw switches came out - Featherweight and Missileworks - that is all I use or recommend. They are rock solid. The Missileworks ones now come with a guide to help locate the switch. After being at the Spaceport America Cup and seeing every single manifestation of a switch implemented, it solidified my commitment to screw switches. Just an FYI, I didn't see any screw switches at the Spaceport.

Edward
Edward, my opinion is in line with yours. That said, I am considering try the Eggfinder WiFi switch.

#### AlphaHybrids

##### Well-Known Member
Edward, my opinion is in line with yours. That said, I am considering try the Eggfinder WiFi switch.
Mark - I have an Eggfinder WIFI. I have used it for certain applications - especially turning on my data recording board that is buried within my rocket. For mission critical, screw switches every time.

Edward

#### ericm541

##### Well-Known Member
Just use those 110/220 rotary switches they are simple and cheap.

#### markg

##### Well-Known Member
Outstanding. Does this "ruling" also apply to the Quantum?
Does that apply to the TRS as well? Can I plug the battery to my TRS without a switch at the flight line, leaving it unarmed until the rocket is on the pad, then arm it with the LCD receiver?

#### caveduck

##### semi old rocketeer
I'm using Fingertech screw switches now (based on some other thread here) and really liking them. They are made for combat robots and are really sturdy with high current capacity. Previously used Schurter rotaries...too flimsy, they can self-destruct on a hard landing and the post-mortem supported that concern. The WiFi switch is functionally great but needs more space and battery.

#### blackjack2564

##### Crazy Jim's Gone Banana's
TRF Supporter
Fingertech screw switches when it really matters.
Missleworks screw on many.
Twist & tape for most sport flying.

#### Garrace

I really like the pull pin snap type switches. They fail safe to normally closed. I have used them for years in the aircraft industry for position indicating switches and don’t recall having any failures short of smashing one. They are small and can be used in tandem for redundant altimeters etc. I think perfect flight sells them for about $5. You do have to epoxy a small tube for the pull pin but easy to do #### markkoelsch ##### Well-Known Member Just use those 110/220 rotary switches they are simple and cheap. I used to use them. I was helping a friend prep a large rocket, and so literally had a Schurter rotary switch come apart in my hand. This changed my opinion, and I went to the Missileworks screw switches. On smaller rockets I do sometimes use twist and tape. #### Steve Shannon ##### Well-Known Member TRF Supporter Does that apply to the TRS as well? Can I plug the battery to my TRS without a switch at the flight line, leaving it unarmed until the rocket is on the pad, then arm it with the LCD receiver? I’m no expert on Eggtimer products but I would expect that all of them that work like the WiFi Switch would fall under the same approval. #### rharshberger ##### Well-Known Member I’m no expert on Eggtimer products but I would expect that all of them that work like the WiFi Switch would fall under the same approval. The TRS is not a wifi device like the other Wifi Switch, and Quantum, it would probably still require a switch, since once the battery is connected it is powered up. #### Cl(VII) ##### Chris Bender, Lab Rat TRF Sponsor I really like the pull pin snap type switches. They fail safe to normally closed. I have used them for years in the aircraft industry for position indicating switches and don’t recall having any failures short of smashing one. They are small and can be used in tandem for redundant altimeters etc. I think perfect flight sells them for about$5. You do have to epoxy a small tube for the pull pin but easy to do
Same switch, but with integrated pin guide. I also have the double switch version in the store. Both come with mounting hardware and pull-pin. They have been quite popular.

Single: https://www.labratrocketry.com/product-page/pull-pin-switch-kit
Double: https://www.labratrocketry.com/product-page/double-pull-pin-switch-kit

#### Garrace

##### Well-Known Member
Very nice I just ordered a bunch. Lol. Worth it just for the pins so I won’t poke myself in the butt with the pointy ones I made when I put them in my pocket. They look very good and the price is right.
Thanks
Gary

#### Steve Shannon

##### Well-Known Member
TRF Supporter
The TRS is not a wifi device like the other Wifi Switch, and Quantum, it would probably still require a switch, since once the battery is connected it is powered up.
Thanks for the clarification! In that case I agree, there must be some kind of switch to kill power that could ignite any charges.

#### rharshberger

##### Well-Known Member
Thanks for the clarification! In that case I agree, there must be some kind of switch to kill power that could ignite any charges.
Might not be a bad idea to double check with Cris Erving though they are his design after all, the TRS does require a "start flight" command from the LCD controller before actually arming before flight, but iirc its not a coded system like the Wifi devices are so it might be possible to arm it with another LCD init on the same freq and ID in someone elses possesion.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
It's not likely that another LCD receiver would interfere with the TRS' arming because both the LCD receiver and the TRS have to be in pairing mode first to communicate with each other. Once the two have been paired, the handshake that allows them to pair is complete, the TRS will ignore any further pairing requests, and the LCD receiver will never get a pairing acknowledgment so it will time out and never go into the terminal mode.

#### Steve Shannon

##### Well-Known Member
TRF Supporter
It's not likely that another LCD receiver would interfere with the TRS' arming because both the LCD receiver and the TRS have to be in pairing mode first to communicate with each other. Once the two have been paired, the handshake that allows them to pair is complete, the TRS will ignore any further pairing requests, and the LCD receiver will never get a pairing acknowledgment so it will time out and never go into the terminal mode.
Cris,
One of the things the BoD liked about the WiFi switch was that it was a separate switch, so when it’s output is off, the leads on the avionic FETs (or whatever power switching device you use) are not connected and thus insensitive to a transient. Do the Quantum and TRS also isolate the output devices until the avionics sections are commanded ON?

#### Cl(VII)

##### Chris Bender, Lab Rat
Very nice I just ordered a bunch. Lol. Worth it just for the pins so I won’t poke myself in the butt with the pointy ones I made when I put them in my pocket. They look very good and the price is right.
Thanks
Gary
Thanks. Dropped your order and several others at the post office this morning.

#### CzTeacherMan

##### Well-Known Member
Screw switches are super simple. You can mount them to the sled and keep everything on a single board. All you carry with you is a screwdriver. Easy.
Twist and tuck is the only thing simpler and more reliable.

#### markkoelsch

##### Well-Known Member
Screw switches are super simple. You can mount them to the sled and keep everything on a single board. All you carry with you is a screwdriver. Easy.
Twist and tuck is the only thing simpler and more reliable.
Don’t you mean twist and tape? Things need to be able to be shut off and if they are tucked that is very difficult.

Staff member