Arduino altimeter - dual recovery for less than 20 dollar

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I have been thinking of doing just exactly the same thing as the altduino. I am thinking either the femtoduino and and then combine a break out board with it mounted to a piece of 1/16 plywood or the Teensie which has a header one can use to make a shield. I was also thinking of a barametric altimeter but also a single axis gyro and an accelerometer all on that shield. Also I want 4 output channels and a EEprom for logging. The 4 outputs are for a possible double airstart and a dual deployment. So a three stage rocket or a single stage with just multiple motors going off according the the flight computer. All this is very possible I just need to learn either eagle or Kicad to develope a board that I can then build and install on the Teensie. And buy the way the teensie is an Arduino compatible microcontroller board that is just that "Teensie". The Femtoduino is the smallest arduino compatible board available and someone is working on one with USB connection which the Teensie already has.
 
This is the place I get my PC boards they take gerber files and send you boards. 3 boards minimum. Two layer is $5 a square inch and 4 layer is $10 a square inch.

$5 dollars a square inch is the price you have to pay for prototypes. This is rather expensive and because I do my boards in bulk I can offer them at a cheaper price. If you send me a PM I can send a price list for kits
 
I have been thinking of doing just exactly the same thing as the altduino. I am thinking either the femtoduino and and then combine a break out board with it mounted to a piece of 1/16 plywood or the Teensie which has a header one can use to make a shield. I was also thinking of a barametric altimeter but also a single axis gyro and an accelerometer all on that shield. Also I want 4 output channels and a EEprom for logging. The 4 outputs are for a possible double airstart and a dual deployment. So a three stage rocket or a single stage with just multiple motors going off according the the flight computer. All this is very possible I just need to learn either eagle or Kicad to develope a board that I can then build and install on the Teensie. And buy the way the teensie is an Arduino compatible microcontroller board that is just that "Teensie". The Femtoduino is the smallest arduino compatible board available and someone is working on one with USB connection which the Teensie already has.
I have four different altimeters and one of them is logging data to an EEPROM and 3 pyros output. This need some work still so if you want to contribute to the code feel free. The ideo is to have it open so that people can improve it
https://rocket.payload.free.fr/
I have not played with gyros; accelerometer yet but I am currently playing with a GPS module.
 
OSH Park's $5 per square inch price is for THREE boards, so it's actually $1.66 per square inch, which is not bad at all for what you're getting. They're pretty quick too, and they ship for free. The only thing I don't like about them is having to clip off the remnants of the tab routing that they use to separate boards. I used to use Batch PCB, they were a lot more expensive; maybe that's why they hung it up and transferred everything over to OSH Park. Of course, if you are making 100 or more boards, you can do better...

$5 dollars a square inch is the price you have to pay for prototypes. This is rather expensive and because I do my boards in bulk I can offer them at a cheaper price. If you send me a PM I can send a price list for kits
 
How about getting smt soldered on the board? Has anybody got a good adress?
 
If you want a timer based you should use a simple NE555

If you had a barometric sensor to your device you could change it to an altimeter and downlod my program

What I would also advice is to do the continuity check to make sure that the ematch is good and screwed properly
All the schema are on my site
 
I'd love to find out too. All of the SMT assembly services that I've looked at so far are way too expensive for small quantities (and they define that as anything under 1,000 pieces). I manually apply the solder paste with a SMT pad template, and use a reflow oven to mount the SMT parts on the Eggtimer boards, I've gotten pretty good at it but the parts are large pitch (for SMT). I wouldn't even dare to try the .5 mm pitch parts, there's no way I'd get it right.

How about getting smt soldered on the board? Has anybody got a good adress?
 
Here's what I use, you just need to set the temperature properly and keep an eye on the boards so they don't cook:

https://www.walmart.com/ip/Proctor-Silex-Toaster-Oven-and-Broiler/11317145

I tried the frying pan method, I got better results with an oven, but it may be because of the LCC baro chip; the PCB acts as an insulator preventing the pads from getting heat from below.

I'd love to find a low-volume SMT assembly service, but you can't find anyone that will do it for less than $10 per unit unless you're making at least 1,000 boards. I'm not quite there yet... :)


OK I have found a very cheap reflow oven
has any body tried one of these?
https://www.ebay.fr/itm/UPDATED-T-9..._bbq_Patio_Covers_Heating&hash=item20bd810aea
 
well thanks guys, looks like I could do some of my altimeters using smt components
I can see several advantages
- smt components are cheaper
- board is cheaper because it is smaller
- it is light
however it is more work for me!!!!!
 
From a commercial kit building point of view, I think it all comes down to how much work you're willing to do on your part, vs. the ease of building the kit. The only two SMT parts on the Eggtimer are the baro sensor and the EEPROM, and I could have used a DIP-8 for the EEPROM but I needed to save the space (and SOIC-8's are easy to mount, anyway). By sticking to through-hole parts, yes, it makes the board a bit larger, but people can generally handle soldering those parts. If I gave them a bunch of 0805 resistors on a cut tape and told them to tin the pads and reflow them with their soldering iron, I'd probably get a 90% return rate, at least.

well thanks guys, looks like I could do some of my altimeters using smt components
I can see several advantages
- smt components are cheaper
- board is cheaper because it is smaller
- it is light
however it is more work for me!!!!!
 
and another question, how can you have components on both side of the board?
 
Very easily. Just flip them over. In some cases, doing that might allow you to make the board smaller, if some of the components' outline footprint is significantly larger than their solder pad footprint (i.e. pizo buzzers). In the case of a DIP package, you might be able to squeeze components between the pads... it depends on the size of the components, and how tight you want the soldering tolerance to be. I don't like to go above .050" between pads/vias, if you get too close it's too easy to get solder bridges.

and another question, how can you have components on both side of the board?
 
Just to keep you up to date this is my datalogger + the cable that I am using
So far I have a program that does the following:
- continuity check of the 3 pyro output
- record the altitude against time and store the result in an EEPROM
- dual deployment capability
- flight data can be extracted so that they can be plotted
- selectable altitude for the main
- report the apogee altitude with a serie of beep after the flight

I am not using the third chanel yet but it could be used to do airstart.
I should be fying it soon.
I am using some smaller but quite powerfull transistors ( 17A) and some new USB adaptors
datalogger and cable.jpg101_7418.jpg
 
I have now added the ability to report the altitude in feet.
I have 2 ways of beeping the altitude, now you can have it beeping digit by digit thanks to Leo Nutz code
version 1.3 can be dowloade here
https://rocket.payload.free.fr/Download/AltiDuoV1_3.zip
Note that for the moment I have only modified the Alti Duo code using compilation directives
So when you upload the code you need to play with those line to choose what you want
///#define METRIC_UNIT
#undef METRIC_UNIT
#define BEEP_DIGIT
//#undef BEEP_DIGIT
For those ordering kits just let me know if you want it metric or not and which way you like to report the altitude
 
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Switching to surface mount components is definitely the way to go for reducing cost and increasing reliability. I just went through quite a bit of experimentation myself on this while building my own arduino based board (though mine is a shield for a Mega R3/Due).

Just to sort of reinforce what others have said in this thread and share my experience so far:
- I used Cadsoft Eagle for the PCB design, there is a free version but surface size is limited, it will do dual sided boards
- I bought all of the SMD components from places like DigiKey, Sparkfun, Adafruit, and Newark (if you're in Europe you might have to use Mouser)
- I bought a good soldering station: the Hakko FX-888D with a few good tips
- I bought a hot-air rework station from SparkFun, which turned out to be an absolute necessity for SMD components
- You'll have to use solder paste instead of normal solder, and you'll want to use lead-based to keep the melting temp down and not fry your components (a mistake I made)
- I used OSHPark for the board fab, and the product is amazing, definitely recommended if you're in the states (not sure elsewhere)

I think if you switched to SMD components, you could shrink your board by at least 1/3rd, just take a look at this SMD AtMega 328P (arduino uno).

I would stick with a temp-controlled hot air station over a wal-mart toaster oven, if nothing else because it lets you work on individual parts and perform ad-hoc repairs. Guaranteed you are going to have a few soldering mistakes (too much or not enough solder in places), I had a few.

I think you should put your code up on one of the free version control sites, such as GitHub. This can get you more exposure to help generate more interest in your projects, and also let people easily submit patches and improvements.

Hopefully some of that info is useful =)
Looking forward to watching where your project goes!
 
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I finish with the certifications this week-end and after I plunge with those Arduino. I do have a Hot Air Rework station and a reballing table and quite few experiences with soldering.
 
Switching to surface mount components is definitely the way to go for reducing cost and increasing reliability. I just went through quite a bit of experimentation myself on this while building my own arduino based board (though mine is a shield for a Mega R3/Due).

Just to sort of reinforce what others have said in this thread and share my experience so far:
- I used Cadsoft Eagle for the PCB design, there is a free version but surface size is limited, it will do dual sided boards
- I bought all of the SMD components from places like DigiKey, Sparkfun, Adafruit, and Newark (if you're in Europe you might have to use Mouser)
- I bought a good soldering station: the Hakko FX-888D with a few good tips
- I bought a hot-air rework station from SparkFun, which turned out to be an absolute necessity for SMD components
- You'll have to use solder paste instead of normal solder, and you'll want to use lead-based to keep the melting temp down and not fry your components (a mistake I made)
- I used OSHPark for the board fab, and the product is amazing, definitely recommended if you're in the states (not sure elsewhere)

I think if you switched to SMD components, you could shrink your board by at least 1/3rd, just take a look at this SMD AtMega 328P (arduino uno).

I would stick with a temp-controlled hot air station over a wal-mart toaster oven, if nothing else because it lets you work on individual parts and perform ad-hoc repairs. Guaranteed you are going to have a few soldering mistakes (too much or not enough solder in places), I had a few.

I think you should put your code up on one of the free version control sites, such as GitHub. This can get you more exposure to help generate more interest in your projects, and also let people easily submit patches and improvements.

Hopefully some of that info is useful =)
Looking forward to watching where your project goes!

All the kits are working quite well and so for I have had technical advices from all over the place. The kits are already very small for something using classic components. But I'd like to try a smd version of some of them.
I am in Europe (France) but whatever can posted I will get it. I normally get all my component direct from China.

Thanks for your advices I did not know about the hot air station.
I am already hosting my code on Github but unfortunatelly I have not been really good at uploading my changes (latest stable code is on my site)
I am currently redesigning my boards on Eagles (I was using TCI) and I will then be able to post some board that everybody can open and modify.
So lot's comming up....but it is currently summer and I am flying rockets so I guess I will have more time in September
 
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The decision to use SMT or through-hole parts (assuming that there is a choice) largely depends on the application. For a hobbyist kit, the through-hole parts may be a better choice, because it's easier for most people to solder them. They don't necessarily take up more room; an 0805 package, which is realistically the smallest package that the average hobbyist can hand-solder, is about the same size as a .1"-centered capacitor or a 1/8W resistor placed vertically, but you have the disadvantage of not being able to route traces to the bottom of the component without adding a via. If you're doing a low-run hobbyist product and you expect your audience to have enough skill to solder these parts to the board without bridging them, they're fine, but there's no way you can expect most people to be able to hand-solder something like an ATMega328P-AU quad-pack. The traces are just too close together. You aren't going to really save any money either, because the passive parts are only a few cents each and the expensive parts are either only SMT anyway (i.e. the BMP085) or are about the same price in either package (the ATMega328P).

If you're doing a board that's going to be mass-produced, SMT ends up being cheaper because the assembly is 100% automated, but in small runs (under 1,000 units) the assembly and setup charges are very significant. I got some quotes for mounting the two SMT parts on the Eggtimer, they ranged from $10 to $40 with a 100-piece minimum. There's no way I could give up $10 for assembly and still be able to sell the kit for $40, so I'll stick with doing it myself; I can do it in about 3 minutes from silkscreening to taking it out of the oven. If I did it with a hot air tool, it would probably take closer to 10 minutes.


Switching to surface mount components is definitely the way to go for reducing cost and increasing reliability. I just went through quite a bit of experimentation myself on this while building my own arduino based board (though mine is a shield for a Mega R3/Due).

Just to sort of reinforce what others have said in this thread and share my experience so far:
- I used Cadsoft Eagle for the PCB design, there is a free version but surface size is limited, it will do dual sided boards
- I bought all of the SMD components from places like DigiKey, Sparkfun, Adafruit, and Newark (if you're in Europe you might have to use Mouser)
- I bought a good soldering station: the Hakko FX-888D with a few good tips
- I bought a hot-air rework station from SparkFun, which turned out to be an absolute necessity for SMD components
- You'll have to use solder paste instead of normal solder, and you'll want to use lead-based to keep the melting temp down and not fry your components (a mistake I made)
- I used OSHPark for the board fab, and the product is amazing, definitely recommended if you're in the states (not sure elsewhere)

I think if you switched to SMD components, you could shrink your board by at least 1/3rd, just take a look at this SMD AtMega 328P (arduino uno).

I would stick with a temp-controlled hot air station over a wal-mart toaster oven, if nothing else because it lets you work on individual parts and perform ad-hoc repairs. Guaranteed you are going to have a few soldering mistakes (too much or not enough solder in places), I had a few.

I think you should put your code up on one of the free version control sites, such as GitHub. This can get you more exposure to help generate more interest in your projects, and also let people easily submit patches and improvements.

Hopefully some of that info is useful =)
Looking forward to watching where your project goes!
 
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Boris,

I did some hacking on the altiduo firmware. I changed the continuity beeps some - one beep for apogee, two for main - the beep(s) are long if no continuity and short if there is continuity. I consolidated the beeping code so it supports LED or tones (still need compile flag, but the logic is all in one place). I also have it storing the apogee altitude in eeprom so when the unit starts up it beeps out the last apogee twice before preparing for launch.

Since I cannot attach on TRF, I'll send through email.

Kevin
 
Boris,

I did some hacking on the altiduo firmware. I changed the continuity beeps some - one beep for apogee, two for main - the beep(s) are long if no continuity and short if there is continuity. I consolidated the beeping code so it supports LED or tones (still need compile flag, but the logic is all in one place). I also have it storing the apogee altitude in eeprom so when the unit starts up it beeps out the last apogee twice before preparing for launch.

Since I cannot attach on TRF, I'll send through email.

Kevin

I'm interested in these changes as well. You should be able to post a zip file on TRF?
 
I'm interested in these changes as well. You should be able to post a zip file on TRF?

It does take .txt files. Just save as .ino. A couple of things I want to add - beep out the set altitude during setup. Further I want to have the main altitude settings a little more friendly to US units (like 150, 300, 600, 900 ft).

Kevin

View attachment AltiDuoV1_4.txt
 
It does take .txt files. Just save as .ino. A couple of things I want to add - beep out the set altitude during setup. Further I want to have the main altitude settings a little more friendly to US units (like 150, 300, 600, 900 ft).

Kevin
Many Thanks Kevin
I am at my country side house for the weekend, I that that I should be able to load the code to my datalogger (which should be compatable) and attempt a flight on my Raptor rocket which is a dual deployment
Boris
 
Many Thanks Kevin
I am at my country side house for the weekend, I that that I should be able to load the code to my datalogger (which should be compatable) and attempt a flight on my Raptor rocket which is a dual deployment
Boris

Kevin
Due to some bad wind I could not fly it. However the code is really good and I think that it is safe to fly it because you are not touching the apogee detection.
I will try to fly it next week end
 
Leo
This is a really nice design, make sure you post a video of the flight

I flew the Altiduo with my firmware yesterday. I also had my ALTDuino Logger with the exact same firmware onboard.

Here the comparison of the baro sensors:

MS5611_BMP085_Compare.png


Max altitude difference between the two sensors was 8 feet.

I don't have a video, sorry.
 
I flew the Altiduo with my firmware yesterday. I also had my ALTDuino Logger with the exact same firmware onboard.

Here the comparison of the baro sensors:

MS5611_BMP085_Compare.png


Max altitude difference between the two sensors was 8 feet.

I don't have a video, sorry.

Leo
that is pretty cool so that bmp085 that can be found for less than $2 is quite good after all.
Boris
 
I also flew 3 rockets this week end
- my PLM converted small Amraam with an alti uno (success)

- my mini raptor with my altimulti running kevin's modified program which did not work so welll and I need to investigate why... maybe few things need changing when running it on the alti multi

- and my last flight was today again with my mini raptor and an alti multi running my datalogger program
this was a sucess too see the flight curve

vol raptor 14-07-2013.png
altitude in meters and time in ms
 
It looks like the clocks are not running at the same rate...
 
yes that is a very good point. I do store the time each time I am saving a sample. I need to instagate why it does that ...
This is beta software so anybody with an idea let me know. Code is available on my site.
Leo maybe you have some tips for me....
 
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