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Introducing the Freakduino 900 MHz Long Range Wireless Board v2.1a | Print |
Written by Akiba   
Wednesday, 25 September 2013

I'm proud to introduce the latest addition to the Freakduino family. This is the Freakduino 900 MHz Long Range wireless board. On the outside, it looks fairly similar to the other Freakduino boards, but under the hood, it's tuned to communicate over long distances. This board uses the same radio as the standard Freakduino 900 MHz board but adds a TI CC1190 RF front end. This boosts the transmit power from 10 mW (+10 dBm) to 500 mW (+27 dBm). There's also a low noise amplifier on the receiver which gives the received signal an +11 dB boost (>10X). Altogether, this chip adds +38 dB to the link budget which is massive gain in the wireless world.

I originally designed this circuit a few years back when I was looking for something to do long distance wireless sensor links, on the order of kilometers or tens of kilometers. 2.4 GHz gets a bit hard to drive that far since higher frequencies have more attenuation in free space as well as a difficult time going through objects. Lower frequencies have much less attenuation and are able to travel through obstacles more easily so they're ideal for situations where range is valued over speed. In sensor networks, data rate usually has a low priority compared to battery life and communications range.

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Introducing the Arashi Ethernet Gateway for Wireless Sensor Networks | Print |
Written by Akiba   
Tuesday, 30 July 2013

Iím proud to announce the release of two new designs, the Arashi Ethernet Gateway for both 2.4 GHz and 900 MHz wireless sensor networks. Thereís quite a bit of history for me with this design. Back when there was a meltdown at Fukushima Dai-Ichi in Japan, I grabbed some Wiznet W5100 ICs and put together a circuit that connected to and uploaded radiation data to servers on the internet. This eventually became a design I called the NetRad and was one of the first DIY geiger counters to be uploading radiation data publicly to the internet during the Fukushima crisis.

01 02

In Tokyo Hackerspace, we deployed a few of them when Sean Bonner emailed me to ask me for links to the data and if I wanted to help a fledgling group that he and Joi Ito were working with called RDTN. Later on, Sean, Joi, me, Bunnie, and a cast of others started working together and Safecast was born .

03

Here's a shot of one of our first meetings together in Tokyo with Bunnie, Aaron Huslage, Sean Bonner, Joi Ito, Ray Ozzie, and a bunch of people from Keio University.

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chibiArduino v1.01 Release | Print |
Written by Akiba   
Monday, 29 July 2013

I just packaged up and released chibiArduino v1.01. This release mainly includes support for some new boards that I'll be releasing shortly. The first board will be an 802.15.4/Ethernet gateway that can be used to connect a chibi based local sensor network to the internet. That should be released within the next day or two. The next round of boards coming out afterwards will be long range boards that have powered RF front ends. I'll be explaining more about these boards soon as well.

There is also a bug fix in this version of the stack. A race condition was found in the transmit function. When a frame is transmitted, the radio state machine is put into a transmit state. However if the radio is busy receiving a frame, the state machine won't transition to the transmit state properly. The fix was to check to make sure no frames were being received before transitioning to the transmit state. 

The release links can be found on the chibiArduino page here :)

 
Intermittent Bugs and How to Strike Fear In the Heart of Experienced Devs | Print |
Written by Akiba   
Wednesday, 03 July 2013

I finished a debugging session yesterday where I had to hunt down a troublesome bug in the chibiArduino stack. It was first brought to my attention last week by a user of the chibiArduino stack who couldn't figure out why it would hang sometimes. He was running four devices with each device broadcasting every 0.1 seconds. It unwittingly created a an interesting stress test in the form of a broadcast storm with an average packet being sent and received by each node every 25 msec. This exposed a problem that I hadn't encountered before, which is strange since I feel like I've used the stack quite a bit.

Before I begin, I'd like to announce that there's an update to the chibiArduino stack with a bug fix in it. You can get it by going here. The rest of this post is long and somehow turned into a story about the hunt for this bug so I'm making the announcement at the beginning for those not interested in hunts for nasty bugs :)

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Introducing chibiArduino v1.0 and Freakduino v2.1a | Print |
Written by Akiba   
Friday, 21 June 2013

Whew! I can't believe how much work it was to coordinate the software release of the library and hardware release of the boards together. There was documentation flying all over the place, furious coding, testing on multiple OSes, screenshots, long photography sessions, and somewhere in there, hardware and software testing. I'm glad I did it though because I've been wanting to release a new version of the Freakduino for a long time. Seriously, I've been wanting to do it since 2011, but a series of events changed my whole life. Ha ha ha...

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