bling

...adding a little more bling to a marching band...

This is the code for a set of networked LED controllers (slaves) run by a central host (master). Communications are handled using the nordic semi nRF24L01+ chip. Each slave also has a ATmega328 micro-controller, and a TLC5940 PWM LED driver. The slaves are intended to be powerd by 6-8 VDC from a pair of Li-Ion cells in series. The slave includes a MAX17041 fuel gauge IC to monitor the battery.

The master that I use is a raspberry pi with a some additional hardware.

• An LCD shield with 5 buttons (http://www.adafruit.com/products/1109)
• An nRF24L01+ tranceiver (https://www.sparkfun.com/products/705)

Some day I should put the board design and the rpi hardware design on github too.

The nRF24L01+ is a addressable packet oriented radio with mutiple addresses on which it can 'listen'. Each of thes is called a pipe. A common address is used as a broadcast to all the slaves. Each slave also has a unique private address that the master can use to communicate with just that one slave.

Building the software

Makefile.avr is used to make the image that is loaded onto the slaves. This uses the gcc-avr, avr-libc, and binutils-avr packages for cross compiling the code.

$ make slave_main.hex to build the application code for the AVR

$ make nrf_boot.hex to build the nrf-enabled bootloader.

Makefile.rpi is used to make the executables that are run on the master (currently a raspberry pi). This requires the bcm2835 c libraray to be installed along with the ncurses-dev package.

Master executables:

• make_addr.py -- reads from /dev/random to make up address for the slaves.

• make_sets.py -- writes the tables used by the sequencing code

• master_lcd -- a simple UI that runs on a LCD shield connected to the rpi ()

• master_loader -- used to reprogram the slaves via the nrf radio

• master_probe -- used to scan for what boards are responding...

• show -- an executable that uses the LCD shield to step through a performance

• master_server -- Used to allow control of the show from a basic TCP/IP socket.

• client_cmd -- Use to help ring out the TCP/IP protocol with the master_server program.

• master_ws -- same as master_server but uses websockets (using the libwebsockets library) as opposed to raw bsd sockets.

• http_server -- a simple webserver (also based upon libwebsockets) that will serve up a page to a client to allow the client to form a websocket to master_ws and run the show.

• js/server.js -- will probably replace the above http_server

• js/client.js -- a command line client for master_ws

Network Control

It would be nice to be able to control the system from a remote pad/computer. So turn the raspberry pi into a 'gateway' between the nRF link to the slaves and a control client.

The general idea is to use google protocol.buffers to encode messages that will be exchanged between a remote client and the master across a websocket.

Then, to allow basically any device to control the system, have the master server up a javascript program to the client as long as the client can support websockets.

The master server is based upon the node.js package and the custom code is in the js directory. To use the node package manager to download dependencies, do the following: $ cd js $ npm config set strict-ssl false $ npm install $ npm install nopt

Setup of the master

debian packages required: gcc-avr, avr-libc, and binutils-avr gcc, g++, ncurses-dev libboost-asio, libboost-program-options libprotobuf-dev, protobuf-compiler python-protobuf (in case I write a python client) nodejs node-nopt npm nodejs-legacy??

--- Since node is called nodejs in the default install... $ sudo update-alternatives --install /usr/bin/node nodejs /usr/bin/nodejs 100

Other libs required: git://git.libwebsockets.org/libwebsockets http://www.airspayce.com/mikem/bcm2835/