Node Js, Pi Face and piface-node

Question

I'm currently trying to use the PiFace Digital Board with my Raspberry Pi, I want to do this completely in javascript and Node Js. I have found that there is a piface-node module for Node Js and have installed it.

I now am trying out the example scripts that have written by the maker of this module, for some reason it isn't working. I am wonder if anyone has had any experience with this module and can point me in the right direction.

I navigate to the directory:

pi@raspberrypi ~/fyp/Node Js/node_modules/piface-node $ cd examples/
pi@raspberrypi ~/fyp/Node Js/node_modules/piface-node/examples $ ls
EventBus.js pfio.input.changed.js pfio.inputs.changed.js
example.js pfio.input.hold.js pfio.output.echo.js

Run this line:

pi@raspberrypi ~/fyp/Node Js/node_modules/piface-node/examples $ node pfio.input.changed.js

Then I get these errors:

ERROR: Can not open deviceERROR: Can not send SPI messageBad file descriptor
{ '0': 'pfio.inputs.changed', '1': 222, '2': 0 }
ERROR: Can not send SPI messageBad file descriptor
ERROR: Can not send SPI messageBad file descriptor
{ '0': 'pfio.inputs.changed', '1': 220, '2': 222 }
{ '0': 'pfio.input.changed', '1': 1, '2': false }
ERROR: Can not send SPI messageBad file descriptor

The Pi is the top range one, and it's getting powered from the plug rather than a USB port. So I assume that power isn't an issue.

I just want to get some lights flashing, and get some push buttons showing they've been clicked in the node output.

Thanks

Answer 1

piface-node is pretty much a pass-through to the C libraries, so I'm not 100% familiar with all the error messages and why they happen. But, I'd look at these two things:

1. Do you have the SPI driver enabled?

(from: http://www.farnell.com/datasheets/1684425.pdf)

$ sudo nano /etc/modprobe.d/raspi-blacklist.conf

Insert a hash (#) at the beginning of the line containing spi-bcm2708, so it reads:

#spi-bcm2708

Save and reboot.

2. Do you have the correct permissions to the SPI device?

$ sudo apt-get update
$ sudo apt-get install automake libtool git
$ git clone https://github.com/thomasmacpherson/piface.git
$ cd piface/c
$ ./autogen.sh && ./configure && make && sudo make install
$ sudo ldconfig
$ cd ../scripts
$ sudo ./spidev-setup

And...

example.js is the starting point for the example application, so give this a try:

pi@raspberrypi ~/fyp/Node Js/node_modules/piface-node/examples $ node example.js

• Callum Linington: I looked in example js and there only 3 requires. But i will give it ago.
• darrylh: You're welcome, @No1_Melman ! Everything in the example application is modular and decoupled: most of the components don't even know that the other ones exist. They only communicate through the EventBus. All that example.js does is start up those modules.
• darrylh: I've updated the README.md (at least in the Git repository) to reflect the answers to your question. (github.com/darrylhodgins/piface-node)

Answer 2

I pushed an updated wrapper for PiFace and NodeJS:

npm install piface

more info at https://github.com/ced-dev/piface

works with NodeJS 4.0+ and 5.0+