Dual Deploy Electronics

[tg08]

Hello, just wanted to get a couple tips and tricks before my first dual deploy launch. Is there any tricks veterans use to ensure successful dual deploy launches? Specifically, my biggest concern is wires disconnecting from my EasyMini during flight. Thanks. Also, on an unrelated note, how hard is it to learn how to solder? I'm getting an Eggfinder TX in a bit, and I'm a little worried I mess up while soldering it together and waste $70.

 

[Hobie1dog]

Hello, just wanted to get a couple tips and tricks before my first dual deploy launch. Is there any tricks veterans use to ensure successful dual deploy launches? Specifically, my biggest concern is wires disconnecting from my EasyMini during flight. Thanks. Also, on an unrelated note, how hard is it to learn how to solder? I'm getting an Eggfinder TX in a bit, and I'm a little worried I mess up while soldering it together and waste $70.

make a checklist for the AV bay. if you cannot pull on the wires and have them come out, you're usually good to go.
watch videos on Youtube on how to solder, lots of them on there.

 

[cwbullet]

Check list is always good, and it is always better to watch someone else do it the first time.

 

[manixFan]

As @Hobie1dog says, there are a lot of good ‘how to solder’ tutorials on YouTube. But make sure you watch one geared towards electronics assembly rather than more generic versions. And I would start with a simpler kit, like the Apogee, which is only $15. You can practice your skills with parts that are easier to work with and more heat tolerant. Then maybe try a Quark for $20. If you order them all at once you can quickly step up your skill level, and you’ll have two useful altimeters when you are done. Otherwise there are a ton of learn to solder kits on Amazon, Sparkfun, etc., which are a lot less stressful than starting with an $70 kit.

Good luck,


Tony.

 

[waltr]

What everyone said about tutorials.

Hint, Do NOT use an eggtimer kit as the first thing you put a soldering iron to.

Instead, find some old electronic thingy and take it apart to pull out the PCB.
Practice taking parts off this 'scrap' PCB and putting them back on. This is trash anyway so can not mess it up.
Once you get the 'feel' of how much heat, tinning and soldering parts then go for the Eggtimer.

I also do recommend the Apogee or Quark kits to start.
The Quark is a nice DD unit, simple and fits into smaller rockets.

 

[Andrew Brown]

If you are nervous about your first dual deploy, you can actually "simulate" a dual deploy launch at no risk beyond single deploy. Simply load your airframe for single deploy (main in sustainer) and fly it with your electronics plus motor as a backup charge. Set the motor delay to be a little after apogee. If all goes well, the dual deploy electronics will pop the main at apogee with the motor eject just in case things go wrong plus the nose should separate at programmed altitude. You can even stuff a small parachute in the payload to make sure your harnessing is correct. However, do not skip ground testing....

Wires disconnecting is a legitimate concern. Using the wrong type of wire, not securing the wire, over/under torquing screw terminals, etc can be a problem. You can pull on the wires and bend them around a bit to test out and look for weaknesses. Having proper strain relief really mitigates wires breaking at attachment points. You might just want to ask someone to look things over prior to your launch. Most people are happy to do it and you'll get no shortage of opinions.

Soldering the Eggfinders have gotten a whole lot easier now that Chris is supplying them with the GPS module already soldered on. Definitely practice, but there really are only a few components now. I always have to look up which way the silly LED goes on.

 

[Handeman]

Do an altimeter ground test using the computer, WiFi connection, or apply vacuum to test fire your matches with your flight battery to make sure that works.

When you are ready to fly;
1. The first thing I do for every single DD flight is to check the resistance of the ematches. They should be about 0.8 to 1.2 Ohms. I don't recall ever getting ones that were open or bad, but I've only done 300- 400 matches at this point.
2. Then hook the matches to your terminals on the av-bay, stand back and power up the altimeters and wait for the proper beeps or WiFi indications. If that works, then power down and add your powder charges.
3. At the pad, make sure you get the proper beeps or WiFi indications before installing the igniter and launching.

If you do those 3 checks successfully before flight, it is very unlikely, although not 0%, that the altimeter and matches will fail on the DD flight.

 

[pathtouch]

I will add definitely connect igniters to your electronics first, and power up as a test before adding your charges. I’ve had an altimeter with a low battery fire on startup and if I had charges installed I would have been very surprised. I’ve also heard of altimeters that landed in ponds being reused without testing like this and deploying things on the ground when switched on.

Obviously turn off or disconnect altimeters when loading powder.

Have fun!

 

[tg08]

What everyone said about tutorials.

Hint, Do NOT use an eggtimer kit as the first thing you put a soldering iron to.

Instead, find some old electronic thingy and take it apart to pull out the PCB.
Practice taking parts off this 'scrap' PCB and putting them back on. This is trash anyway so can not mess it up.
Once you get the 'feel' of how much heat, tinning and soldering parts then go for the Eggtimer.

I also do recommend the Apogee or Quark kits to start.
The Quark is a nice DD unit, simple and fits into smaller rockets.

Good to know, I've got a little extra wire laying around I'll practice on, and I'll try and scrounge around for a PCB.

 

[tg08]

If you are nervous about your first dual deploy, you can actually "simulate" a dual deploy launch at no risk beyond single deploy. Simply load your airframe for single deploy (main in sustainer) and fly it with your electronics plus motor as a backup charge. Set the motor delay to be a little after apogee. If all goes well, the dual deploy electronics will pop the main at apogee with the motor eject just in case things go wrong plus the nose should separate at programmed altitude. You can even stuff a small parachute in the payload to make sure your harnessing is correct. However, do not skip ground testing....

Wires disconnecting is a legitimate concern. Using the wrong type of wire, not securing the wire, over/under torquing screw terminals, etc can be a problem. You can pull on the wires and bend them around a bit to test out and look for weaknesses. Having proper strain relief really mitigates wires breaking at attachment points. You might just want to ask someone to look things over prior to your launch. Most people are happy to do it and you'll get no shortage of opinions.

Soldering the Eggfinders have gotten a whole lot easier now that Chris is supplying them with the GPS module already soldered on. Definitely practice, but there really are only a few components now. I always have to look up which way the silly LED goes on.

Yeah, I've conducted ground tests. Unfortunately, my sustainer tube isn't large enough to accommodate my main parachute, so I'll just have to launch it and cross my fingers. Thanks for the information.