Welcome to the Water Rocket Forum, sponsored by The Water Rocket Achievement World Record Association.

The largest, most sophisticated and ground breaking group supporting you, the serious water rocket flyer! Whether you are a beginner or an expert, the WRA2 has something for everyone.

A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

ServoChron(tm) Firmware Update (Dual servo control)

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
Post Reply
User avatar
Mark Chen
WRA2 Member
WRA2 Member
Posts: 179
Joined: Wed Jan 31, 2007 1:13 pm

Re: ServoChron Lite

Post by Mark Chen » Sat Aug 13, 2011 8:46 am

U.S. Water Rockets2 wrote:
Skymeat wrote:Great project! by the look of it you could pack the guts into a super tiny package if you pull the IC.
You obviously know your stuff! We were saving this for a later date, but since you brought it up, we are proud to give you a preview of the newest member of the ServoChron™ family: ServoChron™ Lite!
lite.jpg
The concept behind this design is that you use the launchpad as a configuration tool and set up your parameters and then pop the chip and install it into the socket on your rocket. The whole design is made from a socket and a couple of LEDs and resistors that cost pennies apiece.

The whole controller can be assembled for under $2.00 and weighs less than 1 gram. This means that the ServoChron™ Lite is 1/20th the cost, 1/6th the weight, and 1/4 the size of commercially available products with similar functionality.

By the way, the MSP430 LaunchPad comes with not one, but TWO microcontrollers, so if you purchase a $4.30 launchpad, you have enough microcontrollers to make TWO of these ServoChron™ Lite systems!

Of course, the building of this system is a bit more involved, but can be simplified down to a air wired circuit that fits inside the footprint of the socket. About a dozen solder joints is all you need to build this setup.

We're finalizing some instructions on how best to power the MSP430 and will have schematics available shortly.

If you want to take the idea and adapt it for your own designs, feel free to do so. We want to encourage you to take the idea and expand upon it and spread the work around to help as many people as possible!
Cool idea with the "Light" version of the project.

Any E.T.A. for the plans for this? I am pulling out Tim's old T-8 deploy design idea and trying to make it 100% reliable. For now in ground tests I will just mount the servo on long wires and remotely mount the launch pad board or leave it on the outside of the rocket and ground test everything, then when you have the new plans ready I will put it inside the T-8.


Mark Chen
Team Enterprise

User avatar
Mark Chen
WRA2 Member
WRA2 Member
Posts: 179
Joined: Wed Jan 31, 2007 1:13 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Mark Chen » Sat Aug 13, 2011 8:51 am

U.S. Water Rockets2 wrote:2) There's a guy who lurks all the water rocket forums looking for good ideas to swipe and publish on his personal website as if he thought of them. If we released the source code he could take out the copyright messages and then publish (or sell) the modified code as his own.
In the download zipfile you guys included a licensing agreement that forbids anyone from pirating the design for profit, right? So why not just put the same licensing in the source code and release it? That would make it illegal for anyone to use the source code like that. That way we could play with the code ourselves.


Mark Chen
Team Enterprise

User avatar
Team Seneca
WRA2 Member
WRA2 Member
Posts: 242
Joined: Sun Dec 31, 2006 1:40 am

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Team Seneca » Sat Aug 13, 2011 12:34 pm

Mark Chen wrote:you guys included a licensing agreement that forbids anyone from pirating the design for profit, right? So why not just put the same licensing in the source code and release it? That would make it illegal for anyone to use the source code like that.
He's got no problem pirating music and software from huge companies with teams of lawyers. Then brags about how cleverly he outsmarted their protection. Even when his victims call him out he lies and makes up crazy excuses that everyone sees right through and continues his dirty tricks. What makes you think a "good faith" open source license is going to get his attention for 1 second? I'm surprised he isn't selling his own ServoClone already!


Bill W.
Team Seneca

User avatar
U.S. Water Rockets1
WRA2 Member
WRA2 Member
Posts: 1771
Joined: Sat Feb 03, 2007 3:24 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets1 » Sat Aug 13, 2011 10:49 pm

Team Seneca wrote:He's got no problem pirating music and software from huge companies with teams of lawyers. Then brags about how cleverly he outsmarted their protection. Even when his victims call him out he lies and makes up crazy excuses that everyone sees right through and continues his dirty tricks. What makes you think a "good faith" open source license is going to get his attention for 1 second? I'm surprised he isn't selling his own ServoClone already!
Come on Bill, this is the thread to discuss our ServoChron project. We've gone over this subject before and you're not going to get a leopard to change his spots by complaining endlessly about it. We don't want to have our discussion here all stunk up when you guys start flaming each other again.


Team U.S. Water Rockets
Visit USWaterRockets.com
Visit our Blog
Tune in to our YouTube Channel
Visit our Facebook page
Visit our Twitter Page
Opportunity is missed by most people because it is dressed in overalls and looks like work. --Thomas Edison

User avatar
Team Seneca
WRA2 Member
WRA2 Member
Posts: 242
Joined: Sun Dec 31, 2006 1:40 am

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Team Seneca » Sun Aug 14, 2011 8:57 pm

U.S. Water Rockets1 wrote: Come on Bill, this is the thread to discuss our ServoChron project. We've gone over this subject before and you're not going to get a leopard to change his spots by complaining endlessly about it. We don't want to have our discussion here all stunk up when you guys start flaming each other again.
Sheesh! Sorry for tryin' to defend you guys. I don't know how you guys can stay so level headed after all the crap he does, especially to you!


Bill W.
Team Seneca

User avatar
U.S. Water Rockets1
WRA2 Member
WRA2 Member
Posts: 1771
Joined: Sat Feb 03, 2007 3:24 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets1 » Sat Aug 20, 2011 9:31 pm

Team Seneca wrote:
U.S. Water Rockets1 wrote: Come on Bill, this is the thread to discuss our ServoChron project. We've gone over this subject before and you're not going to get a leopard to change his spots by complaining endlessly about it. We don't want to have our discussion here all stunk up when you guys start flaming each other again.
Sheesh! Sorry for tryin' to defend you guys. I don't know how you guys can stay so level headed after all the crap he does, especially to you!
We can take care of ourselves. If you want to continue fighting you can do it in the forum the admins set up for that.


Team U.S. Water Rockets
Visit USWaterRockets.com
Visit our Blog
Tune in to our YouTube Channel
Visit our Facebook page
Visit our Twitter Page
Opportunity is missed by most people because it is dressed in overalls and looks like work. --Thomas Edison

User avatar
Niel
WRA2 Member
WRA2 Member
Posts: 7
Joined: Tue Sep 06, 2011 11:21 am

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Niel » Tue Sep 06, 2011 1:40 pm

nice job



User avatar
U.S. Water Rockets1
WRA2 Member
WRA2 Member
Posts: 1771
Joined: Sat Feb 03, 2007 3:24 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets1 » Sat Sep 10, 2011 10:09 pm

Niel wrote:nice job
Thank you for your words of encouragement!


Team U.S. Water Rockets
Visit USWaterRockets.com
Visit our Blog
Tune in to our YouTube Channel
Visit our Facebook page
Visit our Twitter Page
Opportunity is missed by most people because it is dressed in overalls and looks like work. --Thomas Edison

Willem
Advanced Member
Advanced Member
Posts: 31
Joined: Fri Jan 13, 2012 5:16 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Willem » Fri Jan 20, 2012 1:06 am

I've got a question (I've sent it as a PM to U.S. Water Rockets2 but i tought I might post it here too.)

I am thinking of using the uMAD from WhooshTronics as a launch trigger, and then use a very small timing. But, the uMAD doesn't close a circuit, it sends a 1/2 second pulse. Now I have some questions about that problem:

1. Can this do any harm to my LaunchPad
2. Does it work? Will it recognize the circuit as 'closed'?

Thanks in advance :D



User avatar
U.S. Water Rockets2
WRA2 Member
WRA2 Member
Posts: 41
Joined: Wed Feb 07, 2007 12:57 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets2 » Fri Jan 20, 2012 5:49 pm

Willem wrote:I've got a question (I've sent it as a PM to U.S. Water Rockets2 but i tought I might post it here too.)

I am thinking of using the uMAD from WhooshTronics as a launch trigger, and then use a very small timing. But, the uMAD doesn't close a circuit, it sends a 1/2 second pulse. Now I have some questions about that problem:

1. Can this do any harm to my LaunchPad
2. Does it work? Will it recognize the circuit as 'closed'?

Thanks in advance :D
Hi Willem,

Do you have any specifications for the pulse that you are referring to? We're familiar with the Original MAD from Aerocon systems, which fires an ejection charge by dumping the battery voltage across an output screw terminal that would damage the ServoChron if you use it "out of the box".

However, the MAD works well with a simple resistor divider that steps the battery voltage down to a safe level. There's also a point on the MAD circuit board where you can connect the ServoChron and the voltage is safe at that point.

We don't know much about the uMAD, and don't know what the pulse looks like. Do you have the specs on the pulse? If not, does the uMAD come with a schematic diagram like the MAD? We could look at that and be able to tell definitively if it will work without any additional components (or if there's a way to connect them together which will work).

With a bit more information, we would be able to offer suggestions.



User avatar
U.S. Water Rockets2
WRA2 Member
WRA2 Member
Posts: 41
Joined: Wed Feb 07, 2007 12:57 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets2 » Fri Jan 20, 2012 6:00 pm

Willem wrote:I've got a question (I've sent it as a PM to U.S. Water Rockets2 but i tought I might post it here too.)

I am thinking of using the uMAD from WhooshTronics as a launch trigger, and then use a very small timing. But, the uMAD doesn't close a circuit, it sends a 1/2 second pulse. Now I have some questions about that problem:

1. Can this do any harm to my LaunchPad
2. Does it work? Will it recognize the circuit as 'closed'?

Thanks in advance :D
Hi again Willem,

Just got your PM about this and it could be good news or bad news. You mentioned that the uMAD puts out 3.3V or 4V pulses to trigger deploy. If this is the case then it will work at 3.3V but 4V would possibly damage the MSP430 over time. If you can confirm the pulse is 0V and goes to 3.3V then the setup should work.

You will need to make sure that the negative battery terminals of the two boards are connected together (nevermind this step if you were planning on using one battery to power the two boards).

One caveat: if the uMAD has a "continuity check" that senses when the deploy charge is connected, the method it uses to sense a complete circuit with the igniter in the charge could cause the ServoChron to register false triggers. Some altimeters have this feature and it can be shut off with configuration settings or jumpers. You would need to disable this feature if the uMAD has it.

Hopefully, this answered your questions.



Willem
Advanced Member
Advanced Member
Posts: 31
Joined: Fri Jan 13, 2012 5:16 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Willem » Fri Jan 20, 2012 6:07 pm

Hi,

I am using a 600mAh battery - 20C Li-Poly battery. These are 3.7V if i am correct? It is this one: http://www.hobbyking.com/hobbyking/stor ... cell_.html

I also sent Whooshtronics an email about this. I got two replies:
The first one:
If you run the uMad from a separate battery then it will generate a 4v pulse across the terminals.
Add a 1k resistor if your other board will only accept a 3.3v input.
PK
And then the second one:

Paul will probably answer this one better, but here goes…
The uMad only pulses an ejection trigger for about half a second. The half a second could possibly charge an electrolytic capacitor that could give you a longer signal if required. Another way would be to trigger an SCR that would give you a constant output current (See the thread in Ausrocketry for the Easy-As RDF trigger)
I think the first one is the most useful: I am assuming this uMad puts out 3.7V if I connect a 3.7V battery.

Also, here is the development thread for the uMAD, I think there is a schematic in it, but I don't have much knowledge about circuit board schematics :P



Willem
Advanced Member
Advanced Member
Posts: 31
Joined: Fri Jan 13, 2012 5:16 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Willem » Fri Jan 20, 2012 6:10 pm

Oops, I forgot to add the development thread: http://www.ausrocketry.com/forum/viewto ... =32&t=2359



User avatar
U.S. Water Rockets2
WRA2 Member
WRA2 Member
Posts: 41
Joined: Wed Feb 07, 2007 12:57 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by U.S. Water Rockets2 » Fri Jan 20, 2012 6:38 pm

Willem wrote:
The uMad only pulses an ejection trigger for about half a second. The half a second could possibly charge an electrolytic capacitor that could give you a longer signal if required. Another way would be to trigger an SCR that would give you a constant output current (See the thread in Ausrocketry for the Easy-As RDF trigger)
The ServoChron uses a feature that allows it to detect changes in the trigger rather than a sustained level, so the servo can be triggered with VERY short pulses. 0.5 seconds is a lifetime in comparison. ServoChron will easily detect this duration for the pulse.
Willem wrote: I think the first one is the most useful: I am assuming this uMad puts out 3.7V if I connect a 3.7V battery.
You shouldn't assume that it puts out 3.7V because there are ways to step that up higher that could be present in any design. But the answer you received indicates that the signal is probably 3.7V nominally, but a good LiPo battery usually has over 4V on the output when fully charged.

The suggestion to tie the boards together through a resistor is similar to the scheme we used to connect the Aerocon Systems MAD. It should do the trick. Just put a 1K resistor between the output wire of the uMAD and the input pin of the ServoChron and have fun!



Willem
Advanced Member
Advanced Member
Posts: 31
Joined: Fri Jan 13, 2012 5:16 pm

Re: ServoChron(tm) Firmware Update (Dual servo control)

Post by Willem » Fri Jan 20, 2012 6:41 pm

Many thanks! I'll search around the house, I'm pretty sure we have some resistors somewhere... Otherwise I'll buy one.

Thanks again for all the help!



Post Reply