Request for a simple deployment device

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The Eggtimer Apogee has a 60-second countdown timer from when you turn on the screw switch until it arms. This gives you time to remove and replace the nose cone after you turn on the screw switch... although we recommend putting an access hole for the screw switch through the airframe and nose cone shoulder so you don't have to remove the nose cone at all.

The problem with timers for apogee deployment is that they don't have any way of sensing apogee, so if you guess the time wrong it's still either going to fire short or long, just like a motor delay. Also, if something happens and you have an "event" (i.e. fins shreadding off), a timer isn't going to get the laundry out when you need it... but an apogee-sensing baro sensor will.
 
The Eggtimer Apogee has a 60-second countdown timer from when you turn on the screw switch until it arms. This gives you time to remove and replace the nose cone after you turn on the screw switch... although we recommend putting an access hole for the screw switch through the airframe and nose cone shoulder so you don't have to remove the nose cone at all.

The problem with timers for apogee deployment is that they don't have any way of sensing apogee, so if you guess the time wrong it's still either going to fire short or long, just like a motor delay. Also, if something happens and you have an "event" (i.e. fins shreadding off), a timer isn't going to get the laundry out when you need it... but an apogee-sensing baro sensor will.
I think the worry is disarming. The air draw from pulling the nose cone off could cause the altimeter to sense launch. You really want a way to disarm anything pyrotechnic from the outside of the rocket....

I agree baro-based systems have advantageous but I would take whatever is available. A 3 axis accelerometer system would be best, but a timer or baro would be better than nothing.
 
I think the worry is disarming. The air draw from pulling the nose cone off could cause the altimeter to sense launch. You really want a way to disarm anything pyrotechnic from the outside of the rocket....

I agree baro-based systems have advantageous but I would take whatever is available. A 3 axis accelerometer system would be best, but a timer or baro would be better than nothing.
Since the baro sensor needs to sense atmosphere, you'd have to have sensing holes somewhere and those would prevent the draw of vacuum that'd fool the electronics into thinking it was a false launch.
 
Since the baro sensor needs to sense atmosphere, you'd have to have sensing holes somewhere and those would prevent the draw of vacuum that'd fool the electronics into thinking it was a false launch.
That's what the switch access hole does... plus you can arm/disarm without removing anything.

Wireless would have been better, of course, but given the cost/size/complexity constraints of a $15 altimeter that wasn't in the cards for the Apogee. You can do that with a Quantum if you wish... but it's a bit more money.
 
Since the baro sensor needs to sense atmosphere, you'd have to have sensing holes somewhere and those would prevent the draw of vacuum that'd fool the electronics into thinking it was a false launch.
I have been able to pull a fair bit of vacuum for a short moment with standard size vent holes. I recommend caution when pulling off a nose cone. Also I recommend checking a Jolly Logic if you pull the cone off, since I have had them get fooled.
 
That's what the switch access hole does... plus you can arm/disarm without removing anything.

Wireless would have been better, of course, but given the cost/size/complexity constraints of a $15 altimeter that wasn't in the cards for the Apogee. You can do that with a Quantum if you wish... but it's a bit more money.
I just looked at the Quantum and that looks really nice. (I am not that into DIY electronics assembly, but I would buy something like that assembled if available.)

Anyway I think you could charge $150 or so for what I am asking for. A slick, well packaged apogee deployment with an integrated battery and wifi switch. I am scared to fly some of my old motor deploy rockets, but rockets are meant to fly and that redundancy would be great. I think the target market would be mid and level 1 HPR. Once you get to level 2 you really want a proper e-bay.
 
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$150 for a single-deploy altimeter? Yikes! That sounds a little Apple-esqe to me... sell the initial run at a ridiculous price, wait for the sales to start dropping as the early adopters fall off, then drop the price a little to get the people on the fence to bite. Then, when everybody is off the fence, come out with a newer version and repeat the cycle.

We don't do that. Every altimeter and tracker that we've every sold, since 2013, is at the same price as its introduction. We don't do the "market price" thing... we build a reasonable profit into the price, and if the cost of some component goes up we should be able to absorb it; conversely, if we figure out a way to make it cheaper, our costs go down and we make a little bit more on it.
 
$150 for a single-deploy altimeter? Yikes! That sounds a little Apple-esqe to me... sell the initial run at a ridiculous price, wait for the sales to start dropping as the early adopters fall off, then drop the price a little to get the people on the fence to bite. Then, when everybody is off the fence, come out with a newer version and repeat the cycle.

We don't do that. Every altimeter and tracker that we've every sold, since 2013, is at the same price as its introduction. We don't do the "market price" thing... we build a reasonable profit into the price, and if the cost of some component goes up we should be able to absorb it; conversely, if we figure out a way to make it cheaper, our costs go down and we make a little bit more on it.
I am in no position to dictate your pricing and you should charge whatever you think is fair and profitable. I suspect packaging all the electronics in something slick like a Jolly Logic is non trivial, especially a device that needs to withstand ejection gases and being rattled around. A Jolly Logic is over $100 and this would have arming and an output so $150 is just my guess. Its worth noting that a device that prevents lawn darts and saves rockets is worth a lot.
 
$150 for a single-deploy altimeter? Yikes! That sounds a little Apple-esqe to me... sell the initial run at a ridiculous price, wait for the sales to start dropping as the early adopters fall off, then drop the price a little to get the people on the fence to bite. Then, when everybody is off the fence, come out with a newer version and repeat the cycle.

This is the single best explanation of consumerism I have ever heard.
 
This is the single best explanation of consumerism I have ever heard.
I just looked at the Quantum and that looks really nice. (I am not that into DIY electronics assembly, but I would buy something like that assembled if available.)

Anyway I think you could charge $150 or so for what I am asking for. A slick, well packaged apogee deployment with an integrated battery and wifi switch. I am scared to fly some of my old motor deploy rockets, but rockets are meant to fly and that redundancy would be great. I think the target market would be mid and level 1 HPR. Once you get to level 2 you really want a proper e-bay.
Alex,

There are a couple of people that can assemble any Eggtimer kit for a very reasonable fee. You could purchase a kit and have Cris drop ship it to one of the people that assemble his kits and then have them ship it to you for under $100.
 
That is tough to make work for a "throw in" deployment device. It would need around 6 inches to be viable.
As mentioned above, to use the magnetic switch you do need to know its orientation. If you get the wrong orientation, you can inadvertently cause it to switch ON and OFF in a single pass of the magnet. I know this because I have tested it with my own FW magnetic switches.
 
I think this is a great idea. I have been asking those I know for years for this exact item. I do a lot of flights like described and that item would sell like crazy but should be a 25-40 dollar item in my view. So here's what i have done so far that works .
Item 1) I used a pico i think called alt1 its dime sized but cost 75. I put it in a cigar tube with battery and screw terms external for the e match wire to a centrifuge vial of powder. I use an 8-inch flexible wire to a screw switch which i run out the vent hole in the body tube by a 1/2 inch. The cigar tube has a metal loop to attach it to the cord. I think Rob from AMW sells them its accelerometer based. works great.

Item 2. I think its a strata logger would have to open to see. I used the same configuration as above but used a small vac line on the cigar tube. I pull the screw switch out the vent rocket vent hole first then the vac tube while packing the rocket. when on the pad I arm with the switch and push the vent tube in so it's just inside the body tube. It has worked flawlessly and i get a chute out at apogee every time. I always make sure the vial with the powder is at the motor and the cigar tube is almost on top of all line cute and bag if used to mitigate the blast to the package. the second event can be used with a cable cutter for the main if you're doing duel deploy.

Item 3. I called it a sled slapper. little different concept. I wanted a av bay single or dual deploy that could be shared by many rockets. I used this in fiberglass rockets. Its a 38mm av bay that has a piston protruding from it. the piston was taken from a car rear hatch. I had a 10-10 rail button inside my rocket. The bottom of the av bay was a 1/2-inch slice of 10-10 rail. Id slide in the assembly on to the rail button so it has a positive stop to push off. That would place the piston top to the bottom of the nose cone. The vent hole was also the hole to arm the alt. the 38mm tube was parallel to the body tube and up against the body tube inside. Each rocket would have the rail button and vet hole placed so the same assy would work in each rocket. The charge in the piston was a e match in a bolt screwed into the bottom of the piston. The amount of powder was the amount that fills the little red cap on the e match almost nothing. No powder blast in the rocket tube
The assy was attached to the cord and was dragged out by the drogue. The main if dual deploy was attached to it and a cable cutter would release the main. I tested it with apogee deployment first. It worked great but one day I lost the entire rocket off the field. I had 4 rockets set up for it and was planing on converting all rockets 3 inch in dia up. The thought was i could drop it in any rocket and have one alt bay. I plan on building another one once i get some time.
Anyway, just sharing some things that might help others.
Id love to see someone make an accelerometer based unit really small with a wired screw switch and external screws for the ematch. Id fly the heck out of it.
 
Alex,

There are a couple of people that can assemble any Eggtimer kit for a very reasonable fee. You could purchase a kit and have Cris drop ship it to one of the people that assemble his kits and then have them ship it to you for under $100.
I saw someone on facebook advertising this. I messaged them with no reply and gave up. I am pretty happy with the regular style altimeters I have and have on order. I like to try new stuff and I heard great things about Cris's products.
 
As mentioned above, to use the magnetic switch you do need to know its orientation. If you get the wrong orientation, you can inadvertently cause it to switch ON and OFF in a single pass of the magnet. I know this because I have tested it with my own FW magnetic switches.
Thanks for the comment. It seems like wifi is the way to go!
 
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I think this is a great idea. I have been asking those I know for years for this exact item. I do a lot of flights like described and that item would sell like crazy but should be a 25-40 dollar item in my view. So here's what i have done so far that works .
Item 1) I used a pico i think called alt1 its dime sized but cost 75. I put it in a cigar tube with battery and screw terms external for the e match wire to a centrifuge vial of powder. I use an 8-inch flexible wire to a screw switch which i run out the vent hole in the body tube by a 1/2 inch. The cigar tube has a metal loop to attach it to the cord. I think Rob from AMW sells them its accelerometer based. works great.

Item 2. I think its a strata logger would have to open to see. I used the same configuration as above but used a small vac line on the cigar tube. I pull the screw switch out the vent rocket vent hole first then the vac tube while packing the rocket. when on the pad I arm with the switch and push the vent tube in so it's just inside the body tube. It has worked flawlessly and i get a chute out at apogee every time. I always make sure the vial with the powder is at the motor and the cigar tube is almost on top of all line cute and bag if used to mitigate the blast to the package. the second event can be used with a cable cutter for the main if you're doing duel deploy.

Item 3. I called it a sled slapper. little different concept. I wanted a av bay single or dual deploy that could be shared by many rockets. I used this in fiberglass rockets. Its a 38mm av bay that has a piston protruding from it. the piston was taken from a car rear hatch. I had a 10-10 rail button inside my rocket. The bottom of the av bay was a 1/2-inch slice of 10-10 rail. Id slide in the assembly on to the rail button so it has a positive stop to push off. That would place the piston top to the bottom of the nose cone. The vent hole was also the hole to arm the alt. the 38mm tube was parallel to the body tube and up against the body tube inside. Each rocket would have the rail button and vet hole placed so the same assy would work in each rocket. The charge in the piston was a e match in a bolt screwed into the bottom of the piston. The amount of powder was the amount that fills the little red cap on the e match almost nothing. No powder blast in the rocket tube
The assy was attached to the cord and was dragged out by the drogue. The main if dual deploy was attached to it and a cable cutter would release the main. I tested it with apogee deployment first. It worked great but one day I lost the entire rocket off the field. I had 4 rockets set up for it and was planing on converting all rockets 3 inch in dia up. The thought was i could drop it in any rocket and have one alt bay. I plan on building another one once i get some time.
Anyway, just sharing some things that might help others.
Id love to see someone make an accelerometer based unit really small with a wired screw switch and external screws for the ematch. Id fly the heck out of it.
These are good thoughts. I am not going to comment too much on the price, other than I view this as a similar product to the Jolly Logic.
 
Alex - I fly almost exclusively with Quantums. I can show them to you at the next RIMRA launch. They are a little bigger than what you are envisioning, but they work great.
 
This is a request to all the electronics companies out there. I would like a simple timer or altimeter that an e-match can be hooked up to that can handle the ejection charge heat/pressure. Imagine something of the form factor of a Jolly Logic except it has a single output for one e-match. Also if it could be magnetically armed that would be ideal. I am thinking of a device that can be put in a simple motor deploy rocket as back up. It could be simply tied to the shock cord and placed in the chamber with the chute.

A timer would likely be easier, activated with g-forces. A baro altimeter would be subject to the ejection pressure and could get damaged. Anyway this is just an open request. I am not sure of the feasibility or the market, but I would love this.
I am working on just a device - based on a PIC12LF1820 - 8-pin microcontroller, it uses a 9V battery for pyro power, a piezo beeper for recovery help as well as two push buttons for timer set as a function of seconds from launch detect.

The current challenges:
  • Launch Detect sensor.
    • I am considering an old-school, two-pin connector shorted out by a lanyard attached to the launch stand.
    • Hall Effect sensor is possible but always problematic to have a reliable system - a magnet on the outside connected to a lanyard attached to the launch stand.
  • Wiring:
    • Copper foil tape on the inside of the body tube to screw terminals on the sustainer forward bulkhead.
    • Simple, wire pair from the side wall or aft thrust ring to the sustainer forward bulkhead.
    • How that all is connected reliably is still an open problem.
The software, schematics, and PCB files will be available in an OpenSource Hardware project.

Comments and wish list are welcome.
 
I am working on just a device - based on a PIC12LF1820 - 8-pin microcontroller, it uses a 9V battery for pyro power, a piezo beeper for recovery help as well as two push buttons for timer set as a function of seconds from launch detect.

The current challenges:
  • Launch Detect sensor.
    • I am considering an old-school, two-pin connector shorted out by a lanyard attached to the launch stand.
    • Hall Effect sensor is possible but always problematic to have a reliable system - a magnet on the outside connected to a lanyard attached to the launch stand.
  • Wiring:
    • Copper foil tape on the inside of the body tube to screw terminals on the sustainer forward bulkhead.
    • Simple, wire pair from the side wall or aft thrust ring to the sustainer forward bulkhead.
    • How that all is connected reliably is still an open problem.
The software, schematics, and PCB files will be available in an OpenSource Hardware project.

Comments and wish list are welcome.
Awesome you are building something like this. My general comment is to aim for a form factor similar to a Jolly Logic and use a small rechargeable battery. It needs a robust case if it is going to be packed into the main recovery section. Wireless arming/disarming would also be a big plus if you can make that work.
 
I have done Hall effect switches in the past, you still have to wire them in the body tube, and need power as well as signal conditioning or use a digital output sensor. That is at a minimum, 3 wires (haven’t seen a one wire device).

The options are:
Inertial, 1D switch (ball bearing and a spring)
Accelerometer (added complexity)
Direct - break away wire
magnetic:
- Hall effect
- reed switch
All options are stinky at worse, high maintenance at best.

I am very open to other suggestions!
 
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