imjustabrian
04-04-2009, 09:06 PM
Has anyone yet looked into connecting to Dallas Semiconductor's 1-Wire and iButton parts?
They have some interesting sense (temp and humidity mostly), ID, memory and other modules that are useful for hobbyist and data logging projects. 1-wire sends and receives on a single signal line, and many devices can connect to the same bus because they're uniquely addressable. They're also hot-pluggable and support auto-discovery, so you can add sensors on the fly without needing to configure them.
General information here:
http://en.wikipedia.org/wiki/1-Wire
http://www.maxim-ic.com/products/1-wire/index.cfm?CMP=WP-7
(Maybe the neatest device is the 1-wire Weather Station, which was developed by Dallas as a tech demonstrator platform and is now available through AAG Electronica of Mexico for about $100:
http://www.aag.com.mx/aagusa/index1.html )
The protocol is similar to I2C, so I would think it might require some fast custom-made C functions in order to work on the SNAPpy modules. There are already working libraries like pyonewire (http://code.google.com/p/pyonewire ) but these use a USB-to-1wire converter on a PC (this does more than just level conversion, it's a protocol converter too); on an embedded device it makes more sense to wire a GPIO pin directly to the 1-wire data line, so pyonewire probably won't work as-is.
I'd really like to see these devices supported, but I don't code in C myself :/
I might be able to help modify the I2C functions if I had the source, or I can also help test code for others as we have several 1wire devices on hand. Let me (or Synapse) know if you're interested. Thanks!
Brian
They have some interesting sense (temp and humidity mostly), ID, memory and other modules that are useful for hobbyist and data logging projects. 1-wire sends and receives on a single signal line, and many devices can connect to the same bus because they're uniquely addressable. They're also hot-pluggable and support auto-discovery, so you can add sensors on the fly without needing to configure them.
General information here:
http://en.wikipedia.org/wiki/1-Wire
http://www.maxim-ic.com/products/1-wire/index.cfm?CMP=WP-7
(Maybe the neatest device is the 1-wire Weather Station, which was developed by Dallas as a tech demonstrator platform and is now available through AAG Electronica of Mexico for about $100:
http://www.aag.com.mx/aagusa/index1.html )
The protocol is similar to I2C, so I would think it might require some fast custom-made C functions in order to work on the SNAPpy modules. There are already working libraries like pyonewire (http://code.google.com/p/pyonewire ) but these use a USB-to-1wire converter on a PC (this does more than just level conversion, it's a protocol converter too); on an embedded device it makes more sense to wire a GPIO pin directly to the 1-wire data line, so pyonewire probably won't work as-is.
I'd really like to see these devices supported, but I don't code in C myself :/
I might be able to help modify the I2C functions if I had the source, or I can also help test code for others as we have several 1wire devices on hand. Let me (or Synapse) know if you're interested. Thanks!
Brian