Hi guys: some folks in the DASH7 community told me about this discussion. I am the lead developer for OpenTag. My email address is at the bottom of the message.
[size=12]First, let me explain a few things about DASH7 and OpenTag.[/size]
Bluetooth and ZigBee are older that DASH7 and more mature, but they are also not open standards, nor are they open source. This may or may not be an issue for you.
DASH7 (ISO 18000-7) is not designed as a cables-replacement technology. In fact, it's a pretty lousy standard to use if your primary goal is to replace a traditional wire: this is because it does not focus on point-to-point "session-based" communications. The DASH7 MAC and data elements are architected in such a way as to make feasible ultra low power, ultra ad-hoc operation. So, it is quite good for sensing and awareness applications where things are moving around, or, from another perspective, where devices spend a lot of time sleeping and the session cannot be guaranteed.
This means that using a DASH7 module would not be as simple as hooking up a serial connector and sending addresses & data. If this is all you want to do, of course this is possible, and I could spin-out a module build for this limited function pretty easily. Or, I could tell you how to do it ... after all, OpenTag is open source, and we LOVE open source developers.
[size=12]The other question here seems to be whether or not DASH7 can work with the Arduino. The answer is yes, and there are various ways to do it.
1. Use a module based on something like the CC430. I said earlier that it's not trivial to create a module for DASH7/OpenTag. The reason is not technical, but that it's hard to assess the market requirements in a way that would allow me to write a consistent OpenTag module interface that could be conformable to most of the them. If you have some requirements you would like to share, please send them. In some cases, it might be easy to get something working.
2. Port arduino (and OpenTag) to the XMEGA. OpenTag should have no problem running on the XMEGA, as XMEGA has a DMA and plenty of resources.
3. Port OpenTag to the Atmega. It is
possible, but it won't be highly optimized. Someone thinks that because OpenTag cannot run on Atmega, it must be bloated. The opposite is true! OpenTag compiles into about 10-16K of program space on the MSP430 or Cortex M3, depending on options. OpenTag was architected to use a DMA because this reduces the number of interrupts and, thus, reduces the power requirement quite substantially. But you can still do it without a DMA. It's just not optimal. Certain radios also have hardware that can basically do the same job as a DMA. I do have one interested party that may well be going down the path of developing an AVR Atmega port that pairs with a TI CC1101 radio, so I'm looking into getting this to run OK without a DMA.
[size=12]On supporting AVR:[/size]
OpenTag is not a huge project. The HW we support is based on a handful of things (in order):
- What products lead to the best price/performance?
- Which companies support ISO 18000-7 and the DASH7 Alliance?
- Which companies send us dev kits?
Atmel is not yet in this matrix. I have nothing against Atmel or the AVR, but there's only so much bandwidth I have (pun intended). Moreover, I find the MSP430F5 core to be lower power, higher performance, and about the same price as the AVR is. The CC430 is also hard to beat in price due to it integration. The Cortex M3 is a brute -- it can pretty easily do FFT, which is needed for many types of advanced sensors. These are the reasons why I haven't put AVR on the formal roadmap.
If someone else wants to write the AVR port, I will help, but I am too busy right now with the other ports to do the bulk of the job on an AVR port. Let me know if this is something that interests you. As I mentioned, I can hook you up with some guys who are already thinking about an Atmega+CC1101 port of OpenTag.
Lastly, TI is sending us some Chronos watches that we'll get set up with OpenTag. Shouldn't be an issue.
jpnorair_dash7_org (fill in the blanks)