Water Rocket Servo Timer for Parachute Recovery

[tcarnahan]

[quote="U.S. Water Rockets2"][/quote] Thanks for the tip on the batteries!

Did you give a link to where you bought your batteries?

[U.S. Water Rockets1]

Thanks for the tip on the batteries!

Did you give a link to where you bought your batteries?

We have had good luck with this battery:

http://www.hobbyking.com/hobbyking/stor ... _Etc_.html

[U.S. Water Rockets2]

This image is a correction to the wiring diagram above:

Updated Wiring Diagram

ServoChron_Wiring_Diagram.png (19.22 KiB) Viewed 88 times

Also, for the latest version of the firmware and files, please refer to the following topic for the newest and most recent discussion: http://www.wra2.org/forum/viewtopic.php?f=5&t=1599

[tcarnahan]

I was looking at the documentation you have for this on your website. It says to download the “FETPro430 Lite” software from the the website http://www.elprotronics.com/download.html. That link is bad ... the correct link is:
http://www.elprotronic.com/download.html (note: NO "S").

Thanks for making the resource available to us!

[U.S. Water Rockets2]

I was looking at the documentation you have for this on your website. It says to download the “FETPro430 Lite” software from the the website http://www.elprotronics.com/download.html. That link is bad ... the correct link is:
http://www.elprotronic.com/download.html (note: NO "S").

Thanks for making the resource available to us!

Sorry about the typo. It will be fixed in the next manaul release.

[NoKnowElectro]

Will this servo work? And what is everything else, besides the kit and servo, I will need to make the servo work?

[U.S. Water Rockets1]

We mentioned the servo in the other topic, but to answer your other questions the other things you might need are some wire and a soldering iron and solder. You can pretty much get the whole thing going with:

Battery
MSP430 Launchpad
Servo
Wire
Solder
Soldering Iron
Wire Cutters

Optionally you can add a small push button or toggle switch to detect launch, but most people just use a pair of wires that touch and get separated by a string attached to the launcher.

[Muzza]

Just a couple of quick questions, could someone give me the dimensions of the launch pad board? I have a couple of them on the way, but things take ages to get to this far flung corner of the globe, and I want to get on with building my new payload bay.
Also, would a magnetic reed switch work as a launch detect? I'm thinking of gluing the switch to the inside of the payload bay with a small piece of metal, a magnet with a lead attached to the launcher would then 'stick' on the outside of the rocket until removed by the departing rocket. My concern is whether the G forces of the launch could cause the reed switch to not operate correctly

Muzza

[U.S. Water Rockets]

Just a couple of quick questions, could someone give me the dimensions of the launch pad board? I have a couple of them on the way, but things take ages to get to this far flung corner of the globe, and I want to get on with building my new payload bay.
Also, would a magnetic reed switch work as a launch detect? I'm thinking of gluing the switch to the inside of the payload bay with a small piece of metal, a magnet with a lead attached to the launcher would then 'stick' on the outside of the rocket until removed by the departing rocket. My concern is whether the G forces of the launch could cause the reed switch to not operate correctly

Muzza

Hi Muzza,

The MSP430 LaunchPad is 2 inches by 2.7 inches (closer to 2.6, but the USB connector protrudes a bit over the edge of the board so the simension was rounded up.

A reed switch does indeed work as you suggest. You should mount the switch so that the reed runs parallel to the body of the rocket, so that the g-forces are aling the length of the reed. If you set up so that the magnet is holding the switch closed on the pad and is removed when the launch pulls it off, the contacts will open in the switch and the launch will be detected. The SercoChron software will configure automatically for "break" contact if it senses the contacts are closed when you reset/power up.

A couple teams have used this setup with reed swtiches that came from limit switches in garage-door openers.

[king water rocket]

instead of a servo can it be used to trigger a ejection canisters

[U.S. Water Rockets1]

instead of a servo can it be used to trigger a ejection canisters

The servo control signals are constantly pulsing, even when the servo is stationary, so it would not work as a trigger.

[eyeing72]

I suggest buying from here for the LiPo battery http://www.bigskyhobby.com/Batteries/Li ... p4224.html

[Tommy]

If I had a two stage rocket, could I have the trigger start the timer when the second stage starts, or is it operated off of Gs? If it is, could I use a different switch? I need to do this or else I could get the timing wrong, becausehe simulators don't take into account the seperate stages.

[U.S. Water Rockets1]

If I had a two stage rocket, could I have the trigger start the timer when the second stage starts, or is it operated off of Gs? If it is, could I use a different switch? I need to do this or else I could get the timing wrong, becausehe simulators don't take into account the seperate stages.

There is really no one "right" way to do this. Any way that works is "right". You as the designer can pick the trigger system for your timers and since you designed the triggers and know what makes them start, you can adjust and set the timers to the proper values based on what you know and what you simulate.

[Tommy]

If I had a two stage rocket, could I have the trigger start the timer when the second stage starts, or is it operated off of Gs? If it is, could I use a different switch? I need to do this or else I could get the timing wrong, becausehe simulators don't take into account the seperate stages.

There is really no one "right" way to do this. Any way that works is "right". You as the designer can pick the trigger system for your timers and since you designed the triggers and know what makes them start, you can adjust and set the timers to the proper values based on what you know and what you simulate.

What I am going to do is to have a 2 liter top stage fr all the multi staege rockets, and I can have the timer start timing owhen the top stage starts. So I can just time the top stage, and have any assortments of bottom stages with the same setting. I guess what I am asking is is the trip switch a g switch and if it is can I change it out for a different one?