Foot activated launch controller

[Cape Byron]

Just noodling some ideas...

I do a lot of solo prototype flying which makes it hard to launch and observe and get pictures. I figure if I had a foot operated controller I could have both hands free for the cameras. Something like a guitar effects pedal you wouldn't stomp on by accident.

Anyone in TRF land ever built anything like this? I have a Pratt Go-Box which could be easily modded.

 

[Sandy H.]

Never built one, but since you're talking about solo flying and are in a different locale from NAR/TRA rules, I think it should be simple. I assume the Pratt Go-Box is a relay launcher, so simply switching the launch control switch from a low voltage/current switch to a low voltage/current foot pedal should be easy.

I like the concept of using a cheap guitar pedal as the source as they would likely be cheap here in the US at a pawn shop or the local Guitar Center. While I'm not a guitar guy, I can only imagine those pedals are good for 48V, low current as that is what most (US) PA equipment expects.

As long as ratings are observed, a switch is a switch and if the Pratt box is a relay box, then all the real current goes through the box, not the switch. Maybe a series latched switch in the circuit would at least show an attempt at keeping it 'safed' most of the time. Flick the armed switch (latched switch) and then use the foot pedal after the 54321 countdown, just to be extra conservative.

Sandy.

 

[Cape Byron]

Good thoughts. The Go-Box is an early model without a launch key. My idea would be add a key to the Go-Box and run the pedal as an extension switch.

Never built one, but since you're talking about solo flying and are in a different locale from NAR/TRA rules, I think it should be simple.

Do NRA/TRA rules specify that the launch ignition must be from a "Hand operated" launch controller? ie, would a foot switch be a real no-no?

 

[Sandy H.]

I don't think so, but since their rules don't apply at all, zero concern in my mind from a regulatory perspective.

I absolutely do believe that using good practices is always a smart thing, even if the rules don't require it, but at times applying only the rules that apply to your area can relieve unnecessary restrictions (my thought process are cases like where a 2-hand touch scenario in the US requires a 2-person/2-station process in the EU to initiate a press cycle).

I think the concept of a relay based foot actuated launch system would be valid here if a key switch or similar was used. I think the idea for guys launching solo would have a great benefit and I would use one at my solo launches if I took the effort to build one, as you are completely correct that having both hands helps filming for sure.

I am not aware of any rules that says a finger/hand has to be used to initiate a launch vs a foot pedal, so it might be valid for group launches as well, but if your goal is related to solo launches in a non-NAR/TRA environment, I'd say just follow good practices and any rules your locality might have.

Sandy.

 

[rocket_troy]

Another option could be a sewing machine pedal (if you can get them as a spare?) They must have some kind of potentiometer in them so you can perhaps utilise that feature of them to require maximum pedal to activate or even a condition requiring a half pedal for 2 seconds (sounding a warning buzzer) followed by full pedal to activate in series.
Will likely require a simple micro but ... anyway... just some thoughts.

TP

 

[Cape Byron]

Another option could be a sewing machine pedal (if you can get them as a spare?)

Another good thought, and I prolly have one kicking around here...

 

[Cape Byron]

I think the concept of a relay based foot actuated launch system would be valid here if a key switch or similar was used. I think the idea for guys launching solo would have a great benefit and I would use one at my solo launches if I took the effort to build one, as you are completely correct that having both hands helps filming for sure.

I'm sure it would be useful to quite a few of us.

Hmmm. More noodling this afternoon...

 

[teepot]

I'd use one for the same reasons mentioned. I fly at home by my self so something like that would be nice to have.

 

[rcktnut]

Use a metal electrical/project box with a robust momentary switch.

 

[Sandy H.]

Use a metal electrical/project box with a robust momentary switch.

Valid approach, IMO. If you want it to be more of a pedal than a switch, maybe some wood/glue and a pin or two could make it feel that way for no real cost. I imagine auto parts stores here would have a heavy duty switch that would work very well. Almost all the racecars from my early days used a 'Ford solenoid' (Ford starter solenoid powered by 12V that was good for 100+ amps used on a bunch of Fords from the 60's-80's, IIRC) and a sealed/hard toggle pushbutton for starting. You wouldn't need that ampacity, so a simple relay would be fine, but the concept is the same.

I thought sewing machine pedals were analog and not digital, so it would mean you needed to slam the pedal to make sure you don't get a slow build of current until the relay closes.

I still like the idea and hope to see some versions for solo launch guys, but playing Devil's advocate, you'll still move your body a bit when pushing the pedal. If the goal is to get focused on the rocket with your camera, would a better (solo only) option be to use a form of timer switch? You'd get the picture framed and generally focused, flip the 10 second timer switch and then do final framing/focus tweak and then the rocket flies based on the timer input. Making a 1 second beep and/or having an abort foot switch could be features.

Another thought would be to use a dead-man switch to initiate launch. Basically, hold your thumb on a normally closed switch to open it, arm the pad with a normally open switch, frame, focus and then slide your thumb off the dead-man switch with minimal body movement.

Not sure if any of these would be valid for a group launch and/or violate the rules, but just wanted to throw them out in case the end goal (getting good footage) could be done in an alternate way at a solo launch without causing any safety risks or requiring a specific hard to get component.

Good thread!

Sandy.

 

[Cape Byron]

I thought sewing machine pedals were analog and not digital, so it would mean you needed to slam the pedal to make sure you don't get a slow build of current until the relay closes.

I'd gut the pedal and just replace it with a momentary switch.

Initial testing with bare feet and my old R2D2 controller shows it's a reasonable idea... Nice big launch button.

 

[Sandy H.]

From all the other posts from you guys in the southern hemisphere, I assumed bare feet was the equivalent of Russian roulette!!!!

Sandy.

 

[Cape Byron]

From all the other posts from you guys in the southern hemisphere, I assumed bare feet was the equivalent of Russian roulette!!!!

Sandy.

Yeah, that's why I'm looking for something I can use in boots. Gloves. Carrying a firearm...

 

[neil_w]

I still like the idea and hope to see some versions for solo launch guys, but playing Devil's advocate, you'll still move your body a bit when pushing the pedal.

This actually made me hold my hands up in the air as if holding a camera, and then pump my foot up and down as if pushing a switch. This highly controlled scientific experiment suggests to me that this is not a problem to be concerned about.

I would be disinclined to use a timer that runs autonomously. The launch should only occur in reaction to a positive action, not in the absence of a negative one (i.e. an abort).

A timer that runs while a footswitch is depressed (and aborts if the footswitch is released) would solve both of the above problems, but I think a plain old footswitch will do the job just fine.

Good thread!

 

[Steve Shannon]

I don't think so, but since their rules don't apply at all, zero concern in my mind from a regulatory perspective.

I absolutely do believe that using good practices is always a smart thing, even if the rules don't require it, but at times applying only the rules that apply to your area can relieve unnecessary restrictions (my thought process are cases like where a 2-hand touch scenario in the US requires a 2-person/2-station process in the EU to initiate a press cycle).

I think the concept of a relay based foot actuated launch system would be valid here if a key switch or similar was used. I think the idea for guys launching solo would have a great benefit and I would use one at my solo launches if I took the effort to build one, as you are completely correct that having both hands helps filming for sure.

I am not aware of any rules that says a finger/hand has to be used to initiate a launch vs a foot pedal, so it might be valid for group launches as well, but if your goal is related to solo launches in a non-NAR/TRA environment, I'd say just follow good practices and any rules your locality might have.

Sandy.

Just a clarification that if a person wants the protection of NAR or Tripoli insurance, they follow NAR or Tripoli rules even when launching individually.

Also, the functionality of a launch controller is defined not by NAR or TRA rules, but by NFPA 1122 or 1127 which have been adopted as law in most places. A foot switch is not prohibited. Neither are two hands required. There simply must be an arm switch (which doesn’t have to be momentary) and a launch switch which must be momentary. Wiring a foot switch (or better yet, putting in a jack that allows an alternate switch to serve as the launch switch is not a problem.

 

[caveduck]

https://lovemyswitches.com/categories/switches/foot-switches.html for a large selection of guitar pedal stomp switches, including various flavors of the momentary type you need.

 

[tab28682]

If I recall correctly, a number of guys flying S8E competition RC rocket gliders practice with the use a foot switch, so they can launch solo with the radio TX in their hands. I keep meaning to make of if these for myself.

As others have mentioned, as long as the launch controller meets all arming switch and range safety rules, the fact that the ignition switch is foot operated vs hand operated is immaterial.

I can see an easy way to make one with a couple of small pieces of plywood, a hinge, a spring and a heavy duty push button switch. Run it as a extension from a normal launch controller.

This momentary foot switch from Amazon might be a good low cost solution.

https://www.amazon.com/Philmore-LKG...locphy=9027266&hvtargid=pla-309032753885&th=1

 

[GrouchoDuke]

I built this one for my non-club launch days using an arcade button as the trigger. I'm pretty sure I could hit that with my foot. Great idea for launching & still keeping hands free for photography!

 

[Doug Holverson]

Here's the "Shoebox" controller that I made a couple of years back. https://www.rocketryforum.com/threads/the-shoebox.153524/

Embarrassingly, I still haven't painted the thing.

 

[GrouchoDuke]

Here's the "Shoebox" controller that I made a couple of years back.

That is too cool.

 

[Cape Byron]

Here's the "Shoebox" controller that I made a couple of years back. https://www.rocketryforum.com/threads/the-shoebox.153524/

Embarrassingly, I still haven't painted the thing.

Excellent use of a Moon gas pedal!

Thanks for all the responses and positive feedback, guys. Much appreciated.

 

[UhClem]

McMaster-Carr of course has a wide selection of foot switches. (The link is to only a portion.)

 

[curtisheisey]

Why not use foot switch to trigger cameras on a tripod and hands to trigger rocket launch?

Here is a nice heavy, duty foot switch.

https://www.amazon.com/gp/product/B00EF9D2DY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Cape Byron]

Why not use foot switch to trigger cameras on a tripod and hands to trigger rocket launch?

Here is a nice heavy, duty foot switch.

https://www.amazon.com/gp/product/B00EF9D2DY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
View attachment 479289View attachment 479289

I wouldn't be able to track the rocket in the air with the camera on a tripod.

 

[Sandy H.]

Just a clarification that if a person wants the protection of NAR or Tripoli insurance, they follow NAR or Tripoli rules even when launching individually.
[snip]

Good point and now that you pointed it out, even though he's in Australia he could be a NAR member. Sometimes the location blurrs things, but not in that case.

Also, while NFPA might not be what governs their locale, whatever the local rules are should be followed.

Thanks for correcting me, as that was bad information I posted and I wouldn't want to misguide someone, especially if insurance coverage is involved!

Sandy.

 

[Steve Shannon]

Good point and now that you pointed it out, even though he's in Australia he could be a NAR member. Sometimes the location blurrs things, but not in that case.

Also, while NFPA might not be what governs their locale, whatever the local rules are should be followed.

Thanks for correcting me, as that was bad information I posted and I wouldn't want to misguide someone, especially if insurance coverage is involved!

Sandy.

I’m sorry to correct you again, but NAR insurance is only effective in the USA and Canada.
Tripoli insurance is effective there and nearly every other country worldwide.

 

[Doug Holverson]

So would a foot controller be within the rules if you have the safety key and 15+' of cord?

 

[Cape Byron]

So would a foot controller be within the rules if you have the safety key and 15+' of cord?

That was my initial thought.

 

[Sandy H.]

That was my initial thought.

I *think* that is the general agreement understanding (and it is a good idea), but given my recent track record of mis-statements, I'd say the best call is to review local codes and make sure you know the rules of the organization you belong to, if any.

Sandy.

[edit: Changed the word 'agreement' to 'understanding']

 

[Steve Shannon]

So would a foot controller be within the rules if you have the safety key and 15+' of cord?

Yes.