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

Post by **Randino** » Mon Jul 11, 2011 5:25 pm

Where are you ordering the MSP430 LaunchPad board from? I started at this website, (https://estore.ti.com/MSP-EXP430G2-MSP4 ... P2031.aspx) and the site seems to require that I have a company, with a website.

Secondly, since it works on a time delay, do you know of any equations to roughly calculate the length of time from lift off to apogee? If not, I'll just run a few tests and estimate it. As long as I'm close, it shouldn't crash.

Anyways, this looks like an reliable system, I'm looking forward to trying it out, thanks for sharing it.

Post by **WRA2** » Mon Jul 11, 2011 9:34 pm

Randino wrote: Secondly, since it works on a time delay, do you know of any equations to roughly calculate the length of time from lift off to apogee? If not, I'll just run a few tests and estimate it. As long as I'm close, it shouldn't crash.

Hi Randino,

Any one of the computer models for water rockets will work to estimate the time to apogee (time to set delay for)

http://www.wra2.org/Water_Rocket_Simula ... _Links.php

Just input your rocket parameters and you will get a close enough estimate which will work to set your timer for.

Hope that helps you.

Post by **U.S. Water Rockets2** » Tue Jul 12, 2011 5:48 pm

Randino wrote:Where are you ordering the MSP430 LaunchPad board from? I started at this website, (https://estore.ti.com/MSP-EXP430G2-MSP4 ... P2031.aspx) and the site seems to require that I have a company, with a website.

Secondly, since it works on a time delay, do you know of any equations to roughly calculate the length of time from lift off to apogee? If not, I'll just run a few tests and estimate it. As long as I'm close, it shouldn't crash.

Anyways, this looks like an reliable system, I'm looking forward to trying it out, thanks for sharing it.

Hi Randino!

You can indeed get them right from TI. They frequently have free shipping offers at random times during the year. The catch is that you have to fill out an application as a company. Most people just say "self employed" and ho website and they are cool with it.

Other places in the USA you can get the MSP430 LaunchPad to build your own Servo Parachute Deploy are:
http://search.digikey.com/scripts/DkSea ... ad&x=0&y=0
http://www.newark.com/texas-instruments ... dp/77R3863
http://www.mouser.com/ProductDetail/Tex ... b4Vw%3d%3d

People in Europe and Asia can get it from here: http://uk.farnell.com/texas-instruments ... dp/1853793

Lisa had good suggestions for the simulators. The links seem to cover all the sims out there these days. Check that out.

Hopefully, this helps out!

Best Regards,

Post by **U.S. Water Rockets2** » Tue Jul 12, 2011 5:50 pm

Tim Chen wrote:Nice work guys! Thanks for making this available! I look forward to future firmware updates with even more features!

Thanks Tim! It's been a fun project and hopefully will inspire people.

Post by **longpaddle** » Fri Jul 15, 2011 12:20 pm

This looks great and with the cost you can't beat it. Quick question. Can I build the dual servo board and only use a single servo to start with?
I'm new the FC in my rockets so I wanted to start out playing with th eone servo until my rockets get a little more advanced.
With the dual servo board I was thinking that if I want the second servo later I can add it then, as the cost difference is so small from the single servo.

thanks for the cool toys that some of us poor Rocket Dad's can now afford to blast into the air and have come crashing down again.

Adam

Post by **U.S. Water Rockets2** » Fri Jul 15, 2011 2:45 pm

longpaddle wrote:This looks great and with the cost you can't beat it. Quick question. Can I build the dual servo board and only use a single servo to start with?
I'm new the FC in my rockets so I wanted to start out playing with th eone servo until my rockets get a little more advanced.
With the dual servo board I was thinking that if I want the second servo later I can add it then, as the cost difference is so small from the single servo.

thanks for the cool toys that some of us poor Rocket Dad's can now afford to blast into the air and have come crashing down again.

Adam

Adam,

You are welcome! Of course! And thanks for the feedback!

To answer the main question... Yes, you can use this software with only one servo, but you will need to go through the configuration and timer setup steps for the servo that is missing if you choose to go this route.

A better solution is to download the firmware for the single servo version and use that and you will be able to skip the second servo setup steps. If you ever add another servo you can just plug the board into your PC and change the firmware to the dual servo parachute deploy version.

Switching between firmware revisions take about 10 seconds and so you can choose what version you want to run easily.

Click this link for the Single Servo Version: http://www.wra2.org/forum/viewtopic.php?f=5&t=1580

Good luck!

Post by **dutchwaterrocket** » Thu Jul 21, 2011 8:50 am

hi guys,
i've completely build the recovery system. but my servos do not move at all.
is the servochron designed to handle all kinds of servos or only the ones you recommend?
the rest of the system works fine =)
thanks for sharing!

René

Post by **U.S. Water Rockets2** » Thu Jul 21, 2011 6:05 pm

dutchwaterrocket wrote:hi guys,
i've completely build the recovery system. but my servos do not move at all.
is the servochron designed to handle all kinds of servos or only the ones you recommend?
the rest of the system works fine =)
thanks for sharing!

René

Hi Rene'

The system will work in a variety of configurations, depending on the servo you have it may work in the base configuration, or it may need a slight wiring modification. Since there are so many servo types we cannot know for sure which version of the schematic you may need.

The base configuration and wiring disagram is designed to work with the recommended servo. This is the lightest servo on the market with that much torque, making it the lightest system available. This setup includes servoes designed for 3.3V power. Most of the older servos on the market run from 5V power. Most of these will work just fine using our design, but some of them need more than 3.3V to operate. They also may need more current to operate than supplied by the board (very large servos tend to use a lot of current)

In a case where you need more voltage or more current, you can simply move the servo + and - wires directly to the battery input leads and bypass the onboard regulator. This will increase the power supplied to the servos.

If you move the wires to the battery directly, you must make sure to use a battey compatible with the servo input voltage (i.e. do not use a 9V battery to power a servo designed to work on 5V-6V). A cool tip from one of our customers is to power the board and servos with 3 cells taken out of a 9V battery (4.5V).

If you think the design should work with the servos you have already, if you post a picture of the wiring and servos we could look it over and see if there are other changes you can make.

Thanks for the feedback.

Thu Jul 21, 2011 11:00 pm

Rene',

Here is a diagram illustrating how one would wire a 5V servo to the ServoChron(tm) or ServoChron(tm) 2.

: 5V Servo Wiring Diagram; ServoChron2_5V_New.png (213.09 KiB) Viewed 51 times

Most 5V servos are rated to run on 4.8V to 6.0V, but you should check the specs of your servo to be sure the range is acceptable and pick a battery that has the correct voltage.

Good question! This is going into the manual with the next update release!

Post by **dutchwaterrocket** » Fri Jul 22, 2011 5:17 am

Hello uswaterrockets2

I've tried the way you suggested, but it's still not working for me.
when i power up the launchpad with everything connected, my servos make a bit of noise. it sounds like they are underpowered.
sometimes, when i power up the launchpad the servos move but very slow and shaking. i got my servos from: http://www.dealextreme.com/p/sg90-mini- ... rque-35764

i hope you can help me =)

René

Post by **dutchwaterrocket** » Fri Jul 22, 2011 5:19 am

oh yes btw, when i did solder all the wires like the drawing in your manual, my launchpad wouldn't power up at all.
it seemed the + and - wires where wrong. the same thing on this drawing.
it could be my launchpad but in your vid the wires are also different.

thanks for your help =)

René

Post by **U.S. Water Rockets** » Fri Jul 22, 2011 9:25 am

dutchwaterrocket wrote:oh yes btw, when i did solder all the wires like the drawing in your manual, my launchpad wouldn't power up at all.
it seemed the + and - wires where wrong. the same thing on this drawing.
it could be my launchpad but in your vid the wires are also different.

thanks for your help =)

René

It looks like you found a bug in the drawing.

The Red and Black wires near the USB connector are shown with the wrong colors. This is what happens when the engineer does not check the work of the artist.

We're sorry for the confusion. We will update the drawings today and update the manual with your correction.

Keep in mind that if you had issues with the servos while you were running off the USB power, then we still need to look at that problem. The error in the diagram only effects battery operation.

Thank you for pointing this out.

We appreciate the feedback.

Post by **WRA2** » Sun Jul 24, 2011 11:58 am

Use this topic if you have questions about, feature requests or need help troubleshooting the ServoChron(tm) water rocket deployment system.

The release announcements for both can be found at:

http://www.wra2.org/forum/viewtopic.php?f=5&t=1580 For the single servo version.

http://www.wra2.org/forum/viewtopic.php?f=5&t=1599 For the dual servo version.

Post by **DrossMaker** » Wed Jul 27, 2011 1:41 pm

Oops. Was I supposed to put my question here? I asked in the other topic and then noticed this one but I can't edit my post or delete it. Can the admin please fix my mistake. Sorry for the screwup!

Post by **U.S. Water Rockets1** » Sat Jul 30, 2011 9:44 pm

dutchwaterrocket wrote:oh yes btw, when i did solder all the wires like the drawing in your manual, my launchpad wouldn't power up at all.
it seemed the + and - wires where wrong. the same thing on this drawing.
it could be my launchpad but in your vid the wires are also different.

thanks for your help =)

René

In our experimenting we uncovered some scenarios where loading 3rd party programs to the MSP430 LaunchPad can affect how it perform with other programs. Have you used the MSP430 LaunchPad with any other programs or loaded anything other than ServoChron(tm) into it? If so it may be possible to clear the chip and start over and see if that works.

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