I'm happy to announce that after way too long, the new forum is now online . I switched from using the Joomla Fireboard forums, which are no longer being maintained or developed, to phpBB which has a very active development community. The reason for the switch was that the Joomla forums were easily targeted by forum spammers and I started having to spend a lot of time deleting spam posts from bots. Since Fireboard didn't support standard anti-bot tools like reCaptcha and Kismet, bots could essentially have their way with things. I have to admit that when I first started this site, I didn't give much thought to the tools. Truthfully, I didn't expect many people to visit the site so I just chose whatever was easiest. I now realize what a mistake that was. Ha ha ha. 

The forum should be much better with phpBB since it has many options, features, and plugins. I'm also hoping to make it much easier to share code on the forum. The old forum has been archived and can be reached at the forum menu link on the main menu or on the button at the top right side on the new forums. 

Sorry this took longer than expected. Hopefully I can turn this into a nice community hub for wireless sensor network enthusiasts.


I just got back from my vacation in Shenzhen yesterday and was going to relax a bit until Monday when I’d start working on some new designs. When I was reading the New York Times this morning, a particular article caught my attention. Hiroko Tabuchi wrote an interesting article about the worsening crisis going on at the Fukushima Dai-Ichi nuclear power plant.

The radioactive waste water is leaking into the ocean and the leaks seem to be getting larger. There are nearly 1000 tanks at the plant to store the radiated water which are prone to leaks. Also, there are no water level gauges in the tanks and only two men patrol the tanks every day to check for leaks. What caught my attention in the article was when it mentioned TEPCO had no reliable way to check the storage tanks for leaks. That was actually one of those “hmmm….really” moments for me.

Hi folks.

Just wanted to drop a quick note that I'll be on summer holiday from 8/17 to 8/23/2013. I'll be in Shenzhen taking in the geekery with some friends which will not only provide me with a nice break but also hopefully give me inspiration for my next designs. Sorry for the inconvenience and the shop will be open from 8/23.



I’m proud to announce the release of two new designs, the Arashi Ethernet Gateway for both 2.4 GHz and 900 MHz wireless sensor networks. There’s 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.

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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 .


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.

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 :)

A few months ago, I was having a conversation with my friend Nami, who works at a company called Loftwork . Loftwork is a design services firm and also the parent company of Fabcafe in Tokyo. She asked me if I wanted to help out with a project in the company to create a Makers group. The main goal of the group was to find DIY solutions to improve the office. They didn’t have a lot of experience in making things themselves so they asked me and a friend of mine, Joe Moross from Safecast, to help out.

One night over a Loftwork dinner that I invited myself to, we were talking about what projects were needed for the group. Nami and the other members proposed an office improvement project to detect when the women’s toilet was occupied. At Loftwork, the majority of the workers are female. On each floor, there’s a one-toilet men’s bathroom and a one-toilet women’s bathroom. Since there are a lot of women working there, the women’s bathroom is often occupied and the girls keep having to get up from their desk, check the toilet, and if its occupied, have to walk back to their desk. Hence, the Loftwork Womens' Toilet Sensor Project was born.

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 :)