Water Rocket Forum

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

NoKnowElectro wrote:Will this servo work? And what is everything else, besides the kit and servo, I will need to make the servo work(links)?

That servo is a 4.8V to 6V model. It will "probably" work, but we cannot test every single servo to verify it does in fact work. If you happen to have a 4.8V to 6.0V power source then you can modify the wiring to insure that it does work, but the wiring is a little more complicated.

You wire the + and - of the 4.8V to 6V power supply to the + and - leads of the servo and also to the input pads of the MSP430 Launchpad. The servo control signal coming from the Launchpad will go directly to the servo control lead.

This way, the servo gets sufficient power and the Launchpad will run from the same source and the system is happy.

For what it's worth, there are hobby stores online with servos like the one you suggested for much lower prices. Amazon tends to be higher priced than a dedicated hobby shop.

Hopefully, this helps you with your system!

Hello,

I have a suggestion for the ServoChron software. I'm not sure if it is possible but i thought I'd give it a try.

My idea was to add some sort of backup timer, my system is currently activated by the uMAD (Whooshtronics). But whenever that fails, there is no backup in my system. So is there any possibilty to have a backup timer added in case the external detector fails?

Willem wrote:Hello,

I have a suggestion for the ServoChron software. I'm not sure if it is possible but i thought I'd give it a try.

My idea was to add some sort of backup timer, my system is currently activated by the uMAD (Whooshtronics). But whenever that fails, there is no backup in my system. So is there any possibilty to have a backup timer added in case the external detector fails?

Can you explain a little bit more? It sounds like you want two trigger inputs and two independent timer settings. You want one servo to activate with little or no time delay based on an apogee detection input and a second timer to count time from a launch detect switch trigger.

So, a launch event can cause the timer to deploy to start counting. If it expires, then the servo activates. If the apogee detect is triggered before the timer expires, then you want that to take priority?

It sounds like a possibility. If there is a spare input pin that can be used to sense the apogee sensor then it would probably be a minor tweak. We will have to investigate the idea.

Thanks for the suggestion.

Yes, that was my idea. In my case the apogee detector should take priority.

I like your idea on 2 pins, one for the apogee detector and one for the launch detect. It could be made so that one pin always has priority, and the other pin acts as a backup timer in case the pin with the apogee detector fails.

So, when the rocket launches, a wire breaks, resulting in the first timer to start counting. Let's say it is set at a delay of 5 seconds. When the rocket reaches it's altitude, 4 seconds have passed and the apogee detector works fine, so it triggers the servo motor. But, in case the apogee detector failed, the backup timer took over after 5 seconds of launch and the servo motor was triggered by the backup timer which was started at launch. This way the chance that your system fails is much smaller

Willem wrote:Yes, that was my idea. In my case the apogee detector should take priority.

I like your idea on 2 pins, one for the apogee detector and one for the launch detect. It could be made so that one pin always has priority, and the other pin acts as a backup timer in case the pin with the apogee detector fails.

So, when the rocket launches, a wire breaks, resulting in the first timer to start counting. Let's say it is set at a delay of 5 seconds. When the rocket reaches it's altitude, 4 seconds have passed and the apogee detector works fine, so it triggers the servo motor. But, in case the apogee detector failed, the backup timer took over after 5 seconds of launch and the servo motor was triggered by the backup timer which was started at launch. This way the chance that your system fails is much smaller

This sounds like a reasonable modification. There should be a free pin available for this. If there is then it should be possible.

Right then.
I am having a play.
Vero board

POWER SUPPLY

ok, I am going to use a 3.7V lithium battery from an old an knackerd Blackbery phone.
So as it is 3.7V no need for current limiting resistors then.

No need for switches.
Apart from the on off thing, choice is yours.
Now then, I do not really want to chuck my PIC programmer up in the air.
Oh, and the 3.7V battery is light.

Power Supply, come on guy's
10uF 10V and a decoupling cap of 100nF

Vero bought, socket bought, flight next weekend
Simple.
I hope

Now I have to make the parachute....
Hum, next is to check the chip works with it's power supply..........

Update.
I think I can lose the two caps in the supply as I do not need "smoothing" from the 10uF cap or dc blocking from the 100nF
After all, it is from a battery and not mains or USB port powerd.

Any Ideas?
Regards
Mark
(smubbly)

So if i use a 5v servo, can I still use a 9v battery? Thanks!

Also...
I was looking at my board and it looks like they made some changes from the one in the pictures. For one, the component in the middle that you can take out( i dont know what its called) is longer and uses all the holes. Also the connection points on the sides are not holes, they are little pieces of wire sticking out. Should I worry about this?

Here is a picture.

Tommy wrote:Also...
I was looking at my board and it looks like they made some changes from the one in the pictures. For one, the component in the middle that you can take out( i dont know what its called) is longer and uses all the holes. Also the connection points on the sides are not holes, they are little pieces of wire sticking out. Should I worry about this?

This is the second generation of the launchpad board. The part in the center is called a microcontroller and it is like a microprocessor (CPU) with extra features built-in like memory and input/output.

The new board has a CPU with more "legs" that provides extra input/output signals for more advanced projects, but it is said to be compatible with the smaller chip that comes in the older board.

The connection points are soldered into the new board as well, and in the case of the older board they were packaged in the box for the end user to solder in and use if needed. TI makes some plug-in boards that sit on top of these connections and plug in and they decided to mount the pins on the Launchpad because some end users were not good at soldering but wanted to use the add on boards. They made a decision to just solder them on all boards. It doesn't affect the operation but for some applications that don't need the pins on the main board they are a small annoyance. It is easier to solder wires to the board with the holes left open.

We have known for several months that there were new boards released but there's no way to know when placing an order if you will get a new one or old one if a supplier has stock of the old one. Both boards have the same ordering code so you cannot tell which one you are getting.

In the end the new board should work just fine. You may get a warning message when loading the firmware into the chip. If you do get an error let us know and we will try and document a correction. The programming software should ask if you want to program anyway and if you say yes it should work fine.

Thanks for sharing the update. let us know if you have any problems with the new board, so we can get on it right away.

U.S. Water Rockets wrote:This is the second generation of the launchpad board. The part in the center is called a microcontroller and it is like a microprocessor (CPU) with extra features built-in like memory and input/output.

The new board has a CPU with more "legs" that provides extra input/output signals for more advanced projects, but it is said to be compatible with the smaller chip that comes in the older board.

The connection points are soldered into the new board as well, and in the case of the older board they were packaged in the box for the end user to solder in and use if needed. TI makes some plug-in boards that sit on top of these connections and plug in and they decided to mount the pins on the Launchpad because some end users were not good at soldering but wanted to use the add on boards. They made a decision to just solder them on all boards. It doesn't affect the operation but for some applications that don't need the pins on the main board they are a small annoyance. It is easier to solder wires to the board with the holes left open.

We have known for several months that there were new boards released but there's no way to know when placing an order if you will get a new one or old one if a supplier has stock of the old one. Both boards have the same ordering code so you cannot tell which one you are getting.

In the end the new board should work just fine. You may get a warning message when loading the firmware into the chip. If you do get an error let us know and we will try and document a correction. The programming software should ask if you want to program anyway and if you say yes it should work fine.

Thanks for sharing the update. let us know if you have any problems with the new board, so we can get on it right away.

Thanks for replying so quick! I am thinking about getting some plugs for it- on some model planes i have there are connections like those on the side with a plug it goes into. So maybe I can get some of those and use them instead of soldering. That way i could esily replace the board if it breaks.

Also, can i use a 9v battery for some 5v servos? I could use 3 or 4 AAs but I would rather not have the weight.

I have the second gen board and followed the directions listed in the programming manual. When installing the firmware I did get a pop up that stated target is different, I continued with the process and must say everything works great! No issues at all!!

I realized I hadn't posted any photo's of my parachute system yet. It uses the second generation LaunchPad with a 9g servo, a 3.7V LiPo and a uMAD to detect tip-over.
Here is the electronics side of the parachute system:

http://i49.tinypic.com/20t1dnt.jpg (Can't use img tags appearently)

As you can see I ordered jumper cables online so everything can be connected easily. The servo also just plugs in.


By the way USWaterRockets, has development on the launch trigger backup timer already started? (The timer which runs in case the uMAD does not work)


-Willem