MicroPython Forum (Archive)

So I've decided to redo one of my old robots, a micro AUV (autonomous underwater vehicle), and my processor of choice now is (of course) a Cortex-M4 running MicroPython.

http://blog.huv.com/2014/07/nanoseeker-version-2.html for my first thoughts on this, and a couple pictures.

I've been working on the new schematic, since it will require a completely custom board.

nice projects.

Do you already know wich 9-DOF IMU you are going to use?

I have a MPU9150 lying around and a module for that is what's next on my TODO list (after fixing a nasyt bug in my BMP180 module).
What I didn't knew before buying the MPU is that the DMP function it has is pretty much non-usable due to being proprietary crap. Not a big problem for me, as I'm just logging the data, still I'm thinking to look for a more openly documented alternative.

Right now I'm planning on using the MPU-9150. I don't plan on using the built-in DMP, since it only handles six of the nine axes. There are open source Arduino fusion algorithms for this chip, so it should be relatively simple to port one of them to MicroPython.

I've got the schematic done now, next up comes laying out the PCB.

The parts I'm going to use:

• STM32F405 - MicroPython processor
  MPU-9150 - 9-axis IMU
  DRV-8835 (x2) - motor driver chips (2 channels for linear actuators, 1 for thruster)
  MS5803-14BA - pressure (depth) sensor (http://www.meas-spec.com/product/t_product.aspx?id=8684)
  BLE-113 - Bluetooth module (https://www.bluegiga.com/en-US/products ... rt-module/)

The linear actuators, which drive the dive plane and rudder, have a rare earth magnet combined with an analog hall effect sensor to allow me to do closed-loop control of the rudder & dive plane.

The bluetooth module (which doesn't work at all underwater) is to allow me to update the python scripts saved to the built-in file system while the sub is on the bench, without having to open it up to connect USB.

I've started working on the MPU9150.
http://forum.micropython.org/viewtopic.php?f=5&t=231

As an update, I've put together my first new NanoSeeker board, and it is running MicroPython...



Here's a video of it running a simple LED flasher: https://www.youtube.com/watch?v=6JCUt19zGeE

The code is from the wiki: http://micropython.org/doc/tut-leds

This is kinda exactly what I'm trying to build, just mine will have a barometric pressure sensor to measure heigth, because it will go in a rocket.

Awesome.

I'm making a couple changes to my PCB, and ordering a new one. I posted the details on my blog, but basically it comes down to the bluetooth module I chose not being useful in the mode I needed it to work in.

So my new board came in yesterday, and last night I sat down and populated one. It appears to work, and best of all I can pair with the bluetooth module.





You can see large versions of those pictures here and here.

One of my blog posts about NanoSeeker got onto hackaday.com today. It includes a link to micropython.org. So far today I've gotten 3500 page views, which is about 30-40x my normal volume - hopefully it will spark some more interest in MicroPython...

http://hackaday.com/2014/10/25/a-compac ... nanoseeker

- Jon