ServoChron(tm) Firmware Update (Dual servo control)

[U.S. Water Rockets]

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.

You really need to look up the servo specification to be sure that it can handle 9 volts. That is probably more voltage than most servos can handle. But it could vary from one model to another.

You could try finding depleted 9V batteries that have 6 volts or so left in them and use those. Go around and replace all the smoke detector batteries in your house and check the voltages. You could find a depleted one, plus you have made a safer home.

[U.S. Water Rockets]

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!!

Thank you for confirming the operation of the programmer and ServoChron! Your help is appreciated!

[U.S. Water Rockets]

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

Hi Willem,

We ran into a small snag while updating the firmware. We had upgraded the compiler that generates the program when the new version came out a few weeks ago and there is a bug in the new version that causes it to generate an error and fail to make a working program. There is a fix in the works, which will take care of the issue.

Were you able to confirm that you can use your apogee detector with the ServoChron?

[U.S. Water Rockets1]

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)

FYI:

We restored the old compiler from a computer backup and added most of the apogee detect deploy feature. We have to put it through some testing and then document how to use it.

[Azriel]

I must say, despite my reluctance to use electronics on rockets, I find your guys' updating and maintenance of this software absolutely fantastic, especially since it's freeware. I'm sure one day I'll concede to using electronics in my water rockets, and at that time I know I'll be eternally grateful for the updates to the firmware you've published

[U.S. Water Rockets]

I must say, despite my reluctance to use electronics on rockets, I find your guys' updating and maintenance of this software absolutely fantastic, especially since it's freeware. I'm sure one day I'll concede to using electronics in my water rockets, and at that time I know I'll be eternally grateful for the updates to the firmware you've published

Wow, thank you for such high praise. We have really enjoyed our interactions with the community and wanted to share back with everyone who participates. It's nice to hear we have gotten someone to take an interest in the electronics, because that is another passion of ours.

[U.S. Water Rockets]

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

Hi Willem,

We have started documenting the new software version waiting for some good launch weather to run some tests. If you have had success connecting your apogee detector we could add your connection diagram to the manual. If you have a chance to write up a summary it would be a big help.

Thanks.

[Willem]

Hi,

I am on my ipod now so typing is kind of hard. I will write a summary about my setup using the servochron and uMAD apogee detector. It works fairly simple so it won't be too long.

I'm glad I can help you anyways

- Willem

[Willem]

Okay so here's how it works (I'll maybe write a diagram in the afternoon, haven't got much time at the moment.)

I'll start off with the LaunchPad. I use one 3.7V battery which gets connected to the bottom right VCC and GND connectors. The servo power gets connected to the VCC connector above P1.0 and GND gets connected to the GND pin above XIN.

Then there is a power connector just below the USB port. I bend two male jumper cables and put them in those holes so they could not move. The power that comes out of this connector is used to power the uMAD Apogee Detector and maybe some other device in the future, as there are unused cables at the moment.

Now, the trigger signal. When the uMAD tilts towards the ground, it dumps the battery voltage to the two output pins. One is +, one is -. In the beginning I thought it would be hard to connect the outputs correctly to the launchpad but the solution was simple. The output comes from the terminal blocks on the chip. I just connected a cable to the - terminal block output and that got connected to P1.7. This worked perfectly.

So: As soon as I start up the whole parachute system the ServoChron initializes and the uMAD beeps three times to confirm it's working too. Now I have to wait two minutes before the uMAD will give any signal for safety reasons (e.g. tilting the rocket for filling with water or such). After two minutes, the uMAD starts beeping every 5 seconds to tell that it is now armed. As soon as I now tilt over the rocket the uMAD wil give a signal to the servochron, and I've set the timers to a minimal delay so the servo will be rotated almost at the same time the rocket is tilted. This ejects the parachute.


I hope everything is clear this way but this afternoon/evening I will try to make up a diagram of my setup so everything is easier to understand. And, you can use the picture I posted on the bottom of page 4 if something isn't clear. Hope this helps!

- Willem

[Willem]

I modified the image I posted so you can see what each connection does.

raket.png

[U.S. Water Rockets1]

Okay so here's how it works (I'll maybe write a diagram in the afternoon, haven't got much time at the moment.)

I'll start off with the LaunchPad. I use one 3.7V battery which gets connected to the bottom right VCC and GND connectors. The servo power gets connected to the VCC connector above P1.0 and GND gets connected to the GND pin above XIN.

Then there is a power connector just below the USB port. I bend two male jumper cables and put them in those holes so they could not move. The power that comes out of this connector is used to power the uMAD Apogee Detector and maybe some other device in the future, as there are unused cables at the moment.

Now, the trigger signal. When the uMAD tilts towards the ground, it dumps the battery voltage to the two output pins. One is +, one is -. In the beginning I thought it would be hard to connect the outputs correctly to the launchpad but the solution was simple. The output comes from the terminal blocks on the chip. I just connected a cable to the - terminal block output and that got connected to P1.7. This worked perfectly.

So: As soon as I start up the whole parachute system the ServoChron initializes and the uMAD beeps three times to confirm it's working too. Now I have to wait two minutes before the uMAD will give any signal for safety reasons (e.g. tilting the rocket for filling with water or such). After two minutes, the uMAD starts beeping every 5 seconds to tell that it is now armed. As soon as I now tilt over the rocket the uMAD wil give a signal to the servochron, and I've set the timers to a minimal delay so the servo will be rotated almost at the same time the rocket is tilted. This ejects the parachute.


I hope everything is clear this way but this afternoon/evening I will try to make up a diagram of my setup so everything is easier to understand. And, you can use the picture I posted on the bottom of page 4 if something isn't clear. Hope this helps!

- Willem

Great writeup, Willem!
From your description of how the output port works it makes sense that the ServoChron would sense the change when the output turns on. The signal would normally be weakly pulled high by the internal pull-up resistor and the grounded output would have no trouble chaning the input state and trigger the timer.

The firmware update has only been bench tested. We have a setup showing how to connect to the original Aerocon Systems MAD, bit that is a little more involved and we have not documented it yet.

Thanks for sharing your test result!

[Willem]

No problem ;)
It actually makes sense how the ServoChron recognizes the MAD's signal. At first I was just trying around and this came out as a perfect solution.

I must also thank you for making such awesome software, I wouldn't have been able to do that myself.

[U.S. Water Rockets1]

No problem ;)
It actually makes sense how the ServoChron recognizes the MAD's signal. At first I was just trying around and this came out as a perfect solution.

I must also thank you for making such awesome software, I wouldn't have been able to do that myself.

It's our pleasure. It's great that you have been able to benefit from our work.

[bugwubber]

Just wanted to point out in ServoChron_2_User_Manual_V101.pdf, pg 7, you reference "Go to the website http://www.elprotronics.com/download.html" I think you need to drop the S from elprotronics.com. Don't know if this has been pointed out yet or not.

[U.S. Water Rockets1]

Just wanted to point out in ServoChron_2_User_Manual_V101.pdf, pg 7, you reference "Go to the website http://www.elprotronics.com/download.html" I think you need to drop the S from elprotronics.com. Don't know if this has been pointed out yet or not.

Thanks for the correction.