It's been a long time since I last updated the chibiArduino software. For the most part, the stack has been amazingly stable for the last few years but there were always small things that could be done to improve the stack. These were small features that should have been implemented but kept on getting put off. I'm now re-discovering myself after having many adventures, some time off, and going through a few personal roller coasters. It's been a long road, but I'm happy to be back and excited about wireless sensor networks again. There's really a lot of interesting stuff going on and in some strange way, things took a turn up my alley. I'm completely shocked that people are interested in low power, wide area networks (LPWANs) now and also on outdoor, medium/long range wireless sensor networks. In any case, there will be more discussion about that, about some exciting new devices coming out, some hard realizations I've had about myself, and perhaps some ruminations on wireless sensor networks too. So let's get to the release.
One of the main things I did for this release was to enable the various PHY modes. Previously, there were only two data rates supported at 900 MHz (250 kbps and 40 kbps) and one data rate supported at 2.4 GHz (250 kbps). I've added support for a whole slew of data rates at 2.4 GHz: 2 Mbps, 1 Mbps, 500 kbps, and 250 kbps. The range drops off as the speed increases but in some cases, there might not be a need for range as much as throughput so that option is there.
At 900 MHz, I've enabled 1 Mbps, 500 kbps, and both 40 kbps and 20 kbps with BPSK. Previously, BPSK only supported 40 kbps. The higher rates are interesting but what's really exciting is the BPSK-20 PHY mode. At 900 MHz, two types of modulation are supported: OQPSK (offset quadrature phase keying) and BPSK (binary phase shift keying). You don't really need to know the details, but BPSK is much simpler than OQPSK. It encodes less data per symbol than OQPSK hence the lower data rate, but in return, it improves the chances of decoding faint signals. This means a great improvement in range. I've already range tested BPSK-40 and it was pretty crazy. Me and my friends couldn't really walk far enough to escape the signal. BPSK-20 should get even better range than that since the data rate is lower.
I've also added support for a bunch of new boards that will be coming out in the next few weeks. These boards will have variations on the AVR MCU and come in various form factors targeted at specific applications. And finally, I fixed one pretty nasty bug that was found when I was helping a freakduino user figure out a problem they had when they re-initialized the stack after waking up from deep sleep.
In general, these will be the first of many updates and releases and I'll be getting much more active on the website. Thanks for taking the time to read through all of this rambling and I hope you like the software release.
Here is the link to the latest release of chibiArduino.
Happy New Year and it's great to be back :)