Micro Python Quadcopter

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Damien
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Posts: 530
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Micro Python Quadcopter

Postby Damien » Tue Nov 04, 2014 1:03 pm

The first big project I want to do with the pyboard is to build a quadcopter. Yes, you can buy quadcopters ready-made, with cameras and everything, but what's the fun in that? :)

A friend is also going to join the journey, and we are going to build 1 quadcopter each. The chassis we have bought is the ST360. It is 360mm diameter and comes with 4 motors and props. Basic specs:
    * chassis diam: 360mm
    * chassis weight: 170g
    * motors: 4 of ST2210
    * motor weight: 80g each
    * motor speed: 1050 rpm per volt
    * motor max current: 10.2A
    * motor thrust: 600g each
    * battery: 3 cell Lipo (11.1V), 2200mAh, 25C discharge (that means it can supply 25*2.2A=55 amps!)
    * battery weight: 190g
    * electronic speed controllers (ESC): 15A with 5V BEC

Here is a picture of the chassis put together, with 1 ESC, battery and pyboard:
qc-chassis-small.jpg
Quadcopter chassis
qc-chassis-small.jpg (97.22 KiB) Viewed 6565 times

It weighs 560g total, so that's a bit less than what is spec'd above which is good!

It is designed so that the maximum thrust of each motor can on its own lift the entire craft.

For the electronics we plan to use:
    * pyboard for control logic (of course!)
    * MPU9150 for gyro (I don't think the accelerometer will alone be enough to control it)
    * BMP085 digital barometer for determining altitude
    * maybe a GPS unit for tracking and automated "go to" commands
    * NRF24L01 for wireless control, connected to another pyboard on the ground

Stay tuned!

Damien
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Posts: 530
Joined: Mon Dec 09, 2013 5:02 pm

Re: Micro Python Quadcopter

Postby Damien » Tue Nov 04, 2014 1:07 pm

Here is a short video with 1 of the motors controlled by the pyboard, using the accelerometer to change the speed: http://youtu.be/9zFYHiPbdQI

Note that it's already starting to take off with just 1 motor, and it's only at about 40% maximum power in that video.

I think I'm going to need a watchdog...

Turbinenreiter
Posts: 260
Joined: Sun May 04, 2014 8:54 am

Re: Micro Python Quadcopter

Postby Turbinenreiter » Tue Nov 04, 2014 1:20 pm

Hell, I think I should join you guys.

* BMP085 digital barometer for determining altitude

Not BMP185?
* MPU9150 for gyro (I don't think the accelerometer will alone be enough to control it)

And the magnetometer!

Damien
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Posts: 530
Joined: Mon Dec 09, 2013 5:02 pm

Re: Micro Python Quadcopter

Postby Damien » Tue Nov 04, 2014 1:34 pm

Turbinenreiter wrote:Not BMP185?

Didn't know about that one... but do you mean BMP180? If it's higher spec, then yes, I'd go for the higher spec one.

We bought the mechanical and electical parts from hobbyking.com. They have a good selection and fast (but expensive) shipping from Hong Kong. Total parts so far cost around 70 pounds, including a battery charger. The chassis with motors is only 25 pounds.

Turbinenreiter
Posts: 260
Joined: Sun May 04, 2014 8:54 am

Re: Micro Python Quadcopter

Postby Turbinenreiter » Tue Nov 04, 2014 1:48 pm

BMP180 is what I mean. The 180 is the newer version of the 085.

I just ordered at Hobbyking, same components that you have. 112€ which really isn't a lot. I used to build RC planes with my dad before I went to Uni in Munich and that money kind of money bought you one brushless motor and one controller, not four.

I have a half finished design for an IMU skin using the bmp and mpu - this is a very good reason to finish it.

If anyone want's to join the fun:
http://www.hobbyking.com
1x #031000132/28592 ST360 Quadcopter Frame w/Motors and Propellers 360mm = $39.66
1x #T2200.3S.25/8934 Turnigy 2200mAh 3S 25C Lipo Pack = $9.75
4x #261000020-0/58262 Flycolor 15 Amp Multi-rotor ESC 2~3S with BEC = $31.48
1x #XT60/9572 Nylon XT60 Connectors Male/Female (5 pairs) GENUINE = $3.75
1x #9190000006-1/49418 HobbyKing B6 AC/DC Compact LiPO/NiMh 50W Charger (EU Plug) = $19.99

PayPal $0.00
Fedex Priority $31.84
Taxes: $0.00
-------------------
Total: $136.47

Damien
Site Admin
Posts: 530
Joined: Mon Dec 09, 2013 5:02 pm

Re: Micro Python Quadcopter

Postby Damien » Tue Nov 04, 2014 2:20 pm

Turbinenreiter wrote:I just ordered at Hobbyking, same components that you have.


Awesome! Yes, your parts list looks almost exactly the same as ours. We also got XT60 connectors, but I think a slightly cheaper battery charger without the AC connection (ie needs 12V input).

I have a half finished design for an IMU skin using the bmp and mpu - this is a very good reason to finish it.


I'll have to buy one from you :) Or get the design and make one as well.

I also want to make some proto-skins: just a blank piece of PCB that fits over the pyboard in the skin position (have half and full skin versions) and has lots of 0.1" holes in it for quickly making up some adaptors. This way you don't have to solder to the pyboard, and it can be reused in different projects.

Turbinenreiter
Posts: 260
Joined: Sun May 04, 2014 8:54 am

Re: Micro Python Quadcopter

Postby Turbinenreiter » Tue Nov 04, 2014 2:25 pm

I'll have to buy one from you :) Or get the design and make one as well.


First you'll have to fix all my mistakes - first time I'm doing a PCB since school and first time with SMD parts.
Same thing with my mpu9150 and bmp180 libs!

blmorris
Posts: 344
Joined: Fri May 02, 2014 3:43 pm
Location: Massachusetts, USA

Re: Micro Python Quadcopter

Postby blmorris » Tue Nov 04, 2014 3:12 pm

I was about to ask where the motor controllers were in that list, but then I figured it out - apparently you really can get four motor BLDC motor controllers at $7.87 each - wow!
"Micro Python Quad-Copter Kit - the perfect gift for your favorite engineer!"
My biggest concern would be trying to use it anywhere near my kids - they are still small enough that it would be quite dangerous to them, and they could quite easily do a lot of damage to it. Still, I think I know what I'll be getting for christmas now :D

I have played a bit with this GPS unit, mostly for precision timing experiments: The Adafruit Ultimate GPS Breakout
Performance is okay with the on-board antenna if operating out in the open, as I assume most quadcopter operation would be. I started writing a parser for the NMEA output, mostly as an exercise in learning string processing in Python. It could be interesting to integrate the receiver chip to make a full GPS/IMU/barometer navigation skin - the GPS receiver itself is pretty simple to integrate - 3.3V power, one UART RX/TX pair, optional battery backup (could even be shared with the pyboard RTC!) and a few optional GPIO for PPS, enable, and fix indicator lines.
Of course there may be better / smaller / less expensive receivers available; this unit has been on the market for a few years already, it just happens to be the one I have used.

-Bryan

blmorris
Posts: 344
Joined: Fri May 02, 2014 3:43 pm
Location: Massachusetts, USA

Re: Micro Python Quadcopter

Postby blmorris » Tue Nov 04, 2014 3:21 pm

Turbinenreiter wrote:First you'll have to fix all my mistakes - first time I'm doing a PCB since school and first time with SMD parts.
Same thing with my mpu9150 and bmp180 libs!


I'd be happy to help on any level with that part, whether review, direct assistance with the design, or even short-run fabrication - board design is the primary thing that i do. My interest in uPy was the ability to write interesting programs for my own hardware designs; you are still better off asking anyone else for help with your Python though :)
-Bryan

Turbinenreiter
Posts: 260
Joined: Sun May 04, 2014 8:54 am

Re: Micro Python Quadcopter

Postby Turbinenreiter » Tue Nov 04, 2014 4:04 pm

@blmorris
Except to get some files to review later today or tomorrow evening.
Schematics are done (thanks to the sparkfun open hardware designs that I used as blueprint).


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