Tangible Wireless IMU, a BLE motion sensor (WIP).
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README.md

Warning !

This repo is not maintained anymore, here is the new one:

https://github.com/medialablasalle/twiz


twi

What?

TWI stands for Tangible Wireless IMU. It is basically composed with a 9 axis IMU and an ARM-BLE SOC made by Nordic Semi, the nRF51822. This repository contains the software to program this CPU, and the PCB can be found here:

https://upverter.com/honnet

How?

Base

Before testing on the custom PCB a cheap dev board can be used:

https://www.aliexpress.com/item/NRF51822-2-4G-Wireless-Module-Wireless-Communication-Module-Bluetooth-module-zigbee-module-DMX512/32260100115.html

...this cheap programmer is fine too:

https://www.aliexpress.com/item/NEW-OB-ARM-Debugger-Programmer-Downloader-Replace-V8-SWD-M74/32668221105.html

Once everything is gathered, most of the nRF51822 bringup procedure can be made thanks to this tuto:

http://www.funwithelectronics.com/?id=168

Workarounds

A few steps might no work when following this tutorial, here are a few solutions:

1) It might not be useful to download the Mentor toolchain, it is incomplete. Instead, the one Linaro one can be used (from the official ARM developers):

https://launchpad.net/gcc-arm-embedded

2) [This section is not useful anymore, Nordic opened access to all the useful files] If you miss the Nordic files you can use git to travel in the past:

https://github.com/Sproutling/nRF51822-OSX-Sample

It won't be the latest version but you should find what you need. The nrf51 SDK install doesn't always work with wine. A Windows XP in virtualbox doesn't alway help but it works with a real windows (vista for example).

3) The linker script used in the tuto's makefile is supposed to be given by Nordic but it doesn't seem to exist anymore (with this name) so this one can be used: gcc_nrf51_blank_xxaa.ld

4) You have to define your exact CPU such as NRF51422_QFAA_C0 in your CFLAGS otherwise it won't compile compile (but you might be using another kind of CPU).

5) In Ubuntu, to be able to use the segger script, you might need to install lib32readline5 even if you use a 64 bits OS.

6) Known issues:

a) If an error such as the following happens, you might need a 32bit verion of libusb:

./JLinkExe: error while loading shared libraries: libusb-0.1.so.4: cannot open shared object file: No such file or directory

This command might help finding the culprit:

apt-file search libusb-0.1.so.4

The following should solve the problem:

apt-get install libusb-0.1-4:i386

b) Similarly, if you get this error:

./JLinkExe: error while loading shared libraries: libjlinkarm.so.4: cannot open shared object file: No such file or directory

The following should solve the problem:

export LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH

In general ldd /opt/JLink/JLinkExe, should help finding which libraries are missing (adapt your path).

Bonus!

  • Video of the 1st blinking test:

http://youtu.be/sgKb9N6MPIM

  • Test IMU (video here):

https://www.aliexpress.com/item/GY-9255-MPU-9255-Sensor-Module-Alternative-MPU9150-MPU9250/32480993227.html

Enjoy!

A lot of awesome nRF51 repo are available on github or bitbucket, but feel free to ask if you need any help:

contact(a)honnet.eu

May the force be with you!

License

Creative Commons NonCommercial License

This project is released under a Creative Commons, Attribution-NonCommercial-ShareAlike, Version 3.0 License: http://creativecommons.org/licenses/by-nc-sa/3.0