Page 1 of 1

arduino altimeter with micro sd and servomotor

Posted: Tue Jun 30, 2015 2:55 pm
by anoymous
Hi all! For our research competences we needed an altimeter with servomotor, because this is the easiest and most reliable way for parachute deployment (I don't trust timers- too much can go wrong). We tried to find the parts for the launchpad alTImeter from USWR, but there was one thing we couldn't find. Then we stumbled upon Arduino, and with a bit of experimenting it was a sound alternative to the alTImeter. The biggest disadvantage was the weight: it weighed about 100 g (for England and US: about 0,22 lb), shell included. However, if one could make it a little bit more compact, it would weigh less. There is much room for improvements. the attachment is the program. You need to seek the libraries yourself, I couldn't upload them. The drawing below is the scheme:
img012.jpg
img012.jpg (578.44 KiB) Viewed 159 times
Some notes:
- I placed it in a pdf because everyone can open that kind of file. just copy paste it in the arduino program. (you can also download the pdf to get some ideas for programming an altimeter for another brand of motherboard)
- We used the Arduino Leonardo motherboard, so probably there are a few adaptations needed if you use another Arduino motherboard.
- On sites with info about Arduino they say that it is very fragile and can't survive a crash. Well, we had quiet some crashes and we only had to repair the solder and change the servomotor.
- the LED is only because it is easy if you can check if it is turned on and the Leonardo doesn't have a light integrated.
- probably it will also work with one button, but the programming is easier with two buttons.
- I think this one costs more than the launchpad alTImeter, so only try to build it if you want an altimeter with memory and/ or you don't find the parts for the alTImeter
-Don't forget to press the button to arm the altimeter and press the other button to disarm the altimeter after it lands!!!!! If you don't, the servomotor won't activate the deployment system again.
- Without a micro sd inserted, the altimeter won't activate the deployment
-If you want extra information, post your question here.
- To WRA2: was this the right place to post this? Or was there a better place?
- A little disclaimer: I wasn't the first one using an arduino as altimeter for a rocket, I am only the first (I think) to post the code. The other one was (at least when we needed it) too egoïstic to post the code online. If you are curious about it, google ALTduino.

So. I think I said everything. I will post here if I did forget something
Have fun!

Re: arduino altimeter with micro sd and servomotor

Posted: Fri Aug 14, 2015 2:31 pm
by Jamie5335
Hello there,

That all looks pretty cool. I have started using the Arduino myself. I uses the Nano. If you are looking for a more lightweight solution with the LED integrated, then I recommend the Nano as it has the LED built onto the board connected to pin 13. Plus it has a on board regulator for the 9V.

This project is similar to mine! I too have decided to move on from the timer approach. The Barometirc deployment system is a good idea and is well presented by US Water Rockets. It seams that your approach is another great example of a cool new water rocket deployment system that uses these 'breakout boards' you can buy. I looked at the code to see that you were making use of the i2C library which I am a big fan of! Does the SD card have some files on that the Arduino accesses? Plus what size is the capacitor between the servo +ve and -ve rails? Is that used to remove electrical noise?

Just wanted to say that it looks great and I look forward to seeing a launch video at some point.

Cheers, Jamie B

Re: arduino altimeter with micro sd and servomotor

Posted: Sun Aug 16, 2015 2:08 pm
by anoymous
I am busy at the moment, but I will give a good answer in a few days.

Re: arduino altimeter with micro sd and servomotor

Posted: Mon Aug 17, 2015 2:37 pm
by anoymous
The capacitor is used as a buffer against the electricity peaks due to the servo motor. I can't find our altimeter right now, so I don't know what size the capacitor was. I'll try to find it before this weekend.
The program makes a txt file where it posts its readings. It isn't the easiest thing to convert to excel, so if you know a way to write it directly in excel, feel free to try. I'll try if I can find some of the raw readings somewhere on a computer (we worked on at least 4 different computers).
actually, we never "moved on" from a timer: we never used it. we needed quick a reliable deploy system, and from what I heard, the timer can fail fairly easy. At first I was planning to make USWR's altimeter, but I couldn't find the same pressure sensor and I didn't want to risk that the ports weren't at the same place. We aren't active in the field right now, but I'll try to post a launch video we already made. that will probably be somewhere next week.

Re: arduino altimeter with micro sd and servomotor

Posted: Sun Dec 25, 2016 11:59 am
by sebswift
I have had great luck using these low-cost arduino products from adafruit for altitude detection:

$10US processor:
https://www.adafruit.com/products/2010

$10US altitude sensor:
https://www.adafruit.com/products/2651

Connect them with 4 wires (I2C) and the sample programs from Adafruit can be adapted easily. The board will drive a mini servo directly (libraries are included with Arduino). Power with 3-4 AAA batteries. Great tutorials on their site:

https://learn.adafruit.com/trinket-gemm ... g?view=all

I use this vibration sensor to detect launch:

https://www.adafruit.com/products/1766

Cheers,
Dave

Re: arduino altimeter with micro sd and servomotor

Posted: Tue Dec 27, 2016 10:34 am
by anoymous
we actually didnt think about launch detecting lol
the program included will just start recording from the moment you turn it on untill you turn it off again
it gives quite a lot of garbage data, but the launch detecting can't fail

Re: arduino altimeter with micro sd and servomotor

Posted: Wed Jan 04, 2017 2:21 am
by Water Rocket Expert
When I was building rockets reguarly, USWR had a texas instruments device they used as a timer for a service and you made your own g sensor with thin wire and coiled it. I think that was the best mechanism for recovery.

Re: arduino altimeter with micro sd and servomotor

Posted: Sat Jan 07, 2017 11:01 pm
by Blenderite
Personally I love the latest USWR system. I only wished that it would be possible to make it smaller. Anonymous, you said you couldn't find the same altitude sensor? I buy mine from SparkFun. Do they not ship to Belgium?

I am not sure how the TI boards are programmed, but I am guessing it isn't something that could be put on a Arduino. The Mini would make for a much smaller package (https://www.sparkfun.com/products/11303).

Although this appears to be a self-contained Arduino board and a OLED screen (https://www.sparkfun.com/products/12923)!! Would that be viable? Just think of the possibilities of this!

Re: arduino altimeter with micro sd and servomotor

Posted: Tue Jan 10, 2017 10:26 pm
by Water Rocket Expert
I had a problem with an Arduino OLED screen getting screen burn after being on for about an hour. It was a timer I was making.

Re: arduino altimeter with micro sd and servomotor

Posted: Fri Jan 13, 2017 9:07 am
by anoymous
Blenderite wrote:Personally I love the latest USWR system. I only wished that it would be possible to make it smaller. Anonymous, you said you couldn't find the same altitude sensor? I buy mine from SparkFun. Do they not ship to Belgium?

I am not sure how the TI boards are programmed, but I am guessing it isn't something that could be put on a Arduino. The Mini would make for a much smaller package (https://www.sparkfun.com/products/11303).

Although this appears to be a self-contained Arduino board and a OLED screen (https://www.sparkfun.com/products/12923)!! Would that be viable? Just think of the possibilities of this!
-the shipping time was a bit too slow :P
i was kinda in a hurry when we needed our parachute deployment
shipping was technically possible, but it would've taken too long b4 it was here.
-i dont think TI boards are compatible with arduino, i thought they had another programming language
-and i don't think the OLED screen is a good idea, it looks kinda fragile... if the parachute fails a single time, the OLED could be broken.
of course, if you want to risk it, it would definitely look good
Water Rocket Expert wrote:I had a problem with an Arduino OLED screen getting screen burn after being on for about an hour. It was a timer I was making.
since when do LED screens get a screen burn that quickly?
you could always try programming some sort of screen saver on it, so it only shows the time when you press a certain button or something :P

Re: arduino altimeter with micro sd and servomotor

Posted: Fri Jun 29, 2018 6:48 am
by abraar_sameer
I am working on the same thing right now and so I have a little question.

The pressure sensor gives highly fluctuating readings when there's a little bit of wind hitting it directly. Plus, when placed inside the electronics bay, it should measure low or high pressure depending on on the position of the hole in the electronics bay. Where exactly do you place the sensor? And do you have any issues because of wind hitting it?

Thanks