Water Rocket Forum

I am wondering if it is possible to chuck the MSP430 Launchpad board and use just the chip that is on the board. This would make the release computer into a much smaller package. Maybe even usable in a T12 FTC rocket.

-DogLover

I saw a pic posted of the system set up w/o the board somewhere I think it is on their website.

DogLover wrote:I am wondering if it is possible to chuck the MSP430 Launchpad board and use just the chip that is on the board. This would make the release computer into a much smaller package. Maybe even usable in a T12 FTC rocket.

-DogLover

We've made a proof of concept a long time ago, and put together most of the documentation. You can see a picture of it on our website: http://www.uswaterrockets.com/shared/menu.htm (2nd image down from the header on the right side) if you are curious. We have not been able to do any test flights because the weather has been unseasonably cold and we were dumped on with a foot of snow this past week.

What is your skill level? We could possibly release a schematic for the design if there are people here who can follow schematics. The step by step directions are not quite in release form yet.

Thanks for the link. I will look into making that myself.

-DogLover

That's a tiny servo. 3.9 gram? So it looks like even though you've soldered directly to the chip, you did so in a way so you can still insert it into launch pad for programming. And that you've done away with the buttons as well? So you just unplug to reset? Sorry, guess what I meant to say is I think I understand how you have it wired up but would love to see the schematic.

I asked about optical apogee detection over on Yahoo, but I'm just going to whistle and quietly walk away from that one. Wow.

bugwubber wrote:

I asked about optical apogee detection over on Yahoo, but I'm just going to whistle and quietly walk away from that one. Wow.

I wouldn't waste any time with that old mailing list. It pretty much died out years ago.
Just ask your question here and I'm sure someone will have an answer for you.

Wow look now. George is posting answers to stuff that was posted here on the old mailing list.



Now, I wonder what his boss will think when he discovers that George is posting on hobby mailing lists while on company time.
I hope he doesn't get fired.

um yeah. So since I'm kinda new here I guess that's a sore subject?

bugwubber wrote:um yeah. So since I'm kinda new here I guess that's a sore subject?

You are correct about it being a sore subject. You will reach a much larger audience here anyways. Most people abandoned those groups about 4 years ago when the Microsoft deal fell through.

George has had some kind of personal vendetta ever since he came into the hobby about 6 years ago. Hopefully he isn't trying to start something again. I also wouldn't want to see him get in trouble at work either. He has an account here on the forum and can join in the discussions here whenever he wants.

Have a good day/night (whatever timezone you are in)

I think this says it all.

Now lets get this thread back on track!

Hey USWR, You guys got a schematic of that thing to post?

bugwubber wrote:That's a tiny servo. 3.9 gram? So it looks like even though you've soldered directly to the chip, you did so in a way so you can still insert it into launch pad for programming. And that you've done away with the buttons as well? So you just unplug to reset? Sorry, guess what I meant to say is I think I understand how you have it wired up but would love to see the schematic.

I asked about optical apogee detection over on Yahoo, but I'm just going to whistle and quietly walk away from that one. Wow.

You asked for a lighter and smaller version right? There was a tiny amount of criticism when the ServoChron came out about the weight, so we put it on a diet, and the critics retreated.

The servo is the 3.7V model that Hobby King sells. We first started using it with the ServoChron because it was the only 3.7V one on the market. You can get a larger servo that works at that voltage now (Hobby King HXT-900) which we also recommend. The thing is that it's a bit fatter and you can't straddle the servo with the IC legs. For that one we solder the parts together to a DIP socket and hot melt glue it to the servo.

You did guess right.... the version in the image was made so that it could be plugged into the MSP430 Launchpad for setup/configuration and then placed inside a rocket for flight. It doesn't get any lighter than that! The DIP socket version is essentially the same procedure.

You can still add your own external pushbuttons if you want, there's nothing that precludes that in the design. We did however boil the LED down to a single one, just so that it was quicker and easier to build. The LEDs are mostly of value for setup. After that, one LED is all you need to know if the thing is alive and ready.

You seem to have a good handle on what you're getting involved with. You obviously don't need step-by-step instructions. We will upload the schematic later today and leave a message here when it's ready.

What I am thinking of is hooking just the battery, servo, and launch detect switch up to a DIP socket and then put the chip in that. Then if I want to reprogram the chip, I just put it into a Launchpad and reset the time or servo position. That way it is a really small package. One thing, can I get a link to the 3.7v servos? I can't seem to find them. I ordered some Hobby King HK15178's a while ago and they don't work with the board. I suppose because they require too high of voltage. any help is appreciated.

-DogLover

DogLover wrote:What I am thinking of is hooking just the battery, servo, and launch detect switch up to a DIP socket and then put the chip in that. Then if I want to reprogram the chip, I just put it into a Launchpad and reset the time or servo position. That way it is a really small package. One thing, can I get a link to the 3.7v servos? I can't seem to find them. I ordered some Hobby King HK15178's a while ago and they don't work with the board. I suppose because they require too high of voltage. any help is appreciated.

-DogLover

My current setup has power going from the battery separately to the board, the servos, an altimeter, and lights so that the servos get all the power they want even though my HXT900s work just fine powered from the board.
For low voltage, have you looked at these?

bugwubber wrote:

DogLover wrote:What I am thinking of is hooking just the battery, servo, and launch detect switch up to a DIP socket and then put the chip in that. Then if I want to reprogram the chip, I just put it into a Launchpad and reset the time or servo position. That way it is a really small package. One thing, can I get a link to the 3.7v servos? I can't seem to find them. I ordered some Hobby King HK15178's a while ago and they don't work with the board. I suppose because they require too high of voltage. any help is appreciated.

-DogLover

My current setup has power going from the battery separately to the board, the servos, an altimeter, and lights so that the servos get all the power they want even though my HXT900s work just fine powered from the board.
For low voltage, have you looked at these?

Nice find with those servos. We havw not seen those before. We will check them out next time we're padding out an order that is underweight.

As promised, here's a draft of the ServoChron(tm) Lite Schematic. This design does work well on the bench. We have not tested this in a real launch, so just be aware it is still in testing. This design is an evolution of one we did test, and that one worked, but this one has a ton of parts removed to make it easier to build and smaller.

http://www.uswaterrockets.com/shared/Se ... inary).pdf

Our primary landing area is now totally off limits as the ice is very thin, so we are not able to launch. Our backup areas are still covered in snow. It could be a couple of weeks before we can launch again.

Let us know how you make out!

USWR- Thank you!

Thanks for that USWR! That will be helpful.

-DogLover