Tokyo HackerSpace’s volunteers take ‘people power’ to radiation monitoring


Tokyo HackerSpace Photo Credit: David Powell

TOKYO (majirox news) – Radiation from the Fukushima Daiichi nuclear plant is not leaking evenly and many parts of the United States have higher radiation levels than Japan, according to, which uses volunteers armed with bento box (lunch box) monitors to gather radiation data.

Safecast, an international volunteer organization, works with Tokyo HackerSpace to help people affected by Japan’s disasters.

“People have a reaction of fear and panic, which I am not saying is unwarranted, but we have found that this type of contamination is not uniform and is spread out in different locations, so unless you go and measure you shouldn’t make blanket statements,” said Pieter Franken, senior visiting researcher at Keio University and co-founder of

“You shouldn’t say ‘don’t go to Fukushima’ or ‘don’t go to Japan.’ If you compare the radiation levels in Japan on a worldwide scale, you will find out that in many places in the United States the radiation levels are higher.” is made up of volunteers who have used their expertise to create a simple-to-use bento box radiation monitor. The system is made with everyday items and operated by ordinary people who check radiation levels and the data they find is posted online.

The system is the first in the world that can be mounted on a car, motorbike or bicycle.

“It uses ordinary batteries and an SD* card, instead of a PC,” Franken, an avid cyclist, told Majirox News. “It has an on and off button, like a recorder. It’s that simple. We call it a bento box, because it’s the size and shape of a bento box.

“The moment you switch it on, it registers the level of radiation in the air and then goes immediately to a Google site map. Anybody on the planet can see what we measured that day.”

Franken added that is now monitoring a larger area than it had been due to having more cars available and it is mapping areas street-by-street in cities across Japan, which are posted on the organization’s site at

“Before, we drove on the big roads and crossed the main cities. We have gone back to these cities and crossed every single street. Like in Google Maps you have the concept turn-by-turn. This is literally turn-by-turn radiation measurement.”

Safecast volunteer Robin Scheibler on his bike with the radiation detection monitor currently operates 10 bento box radiation detection systems, with about 20 people building them. Safecast is working through Tokyo HackerSpace to teach people how to build their own detectors and in the coming months will offer classes. One can also purchase a completed monitor for about 100,000 yen (1,235).

Bento box monitors have discovered that radiation levels have risen, with levels in Chiba prefecture being three to five times higher than radiation in Tokyo. The capital may be three times higher than what is measured in Shizuoka prefecture, to the south. “Compared to before March 11, the city of Koriyama (in Fukushima prefecture) may have a difference of 100 to 300 times,” Franken said. had found cesium 134 and cesium 137 everywhere, but no traces of iodine, an indicator of recent nuclear release activity.

“There seems to be a chemical reaction between cesium and specific surfaces, such as concrete, wood, metal, asphalt, etc.,” he said. “The cesium chemically reacted with the material and baked onto it. We have been seeing this over time when it has been raining and there is wear and tear. The amount of contamination is barely coming down or not at all.”

Governmental agencies have just started mimicking’s methods of monitoring radiation, albeit at a much slower pace.

“They came up with this idea after two and half months while we started two and half months ago,” Franken said. “It doesn’t matter, though. What is important is that more people understand that this is a valid way of attacking the problem.”

He noted that the government also uses slightly different equipment than

“We are using a system that is sensitive to alpha, beta and gamma radiation,” he said. “They use a different device, designed to measure only gamma radiation.”

Franken added that the bento box system is also the third generation of its design, which means it can be used by anybody, as opposed to being operated by computer or specialists. takes an objective approach which Franken suggested makes the organization’s data preferable to that provided by public bodies.

“People want to have an independent assessment done by people who don’t have vested interests,” he said. It’s like getting a second opinion done by a doctor. “The other reason is that our priorities are slightly different. The government will make an assessment and share it as official data. It may or may not be used to determine whether people should evacuate or not.”

Similar accessibility can be seen in’s use of the data it obtains.

Safecast volunteers at Iwaki in Fukushima prefecture, L to R: Kiki Tanaka, Yamadera-san, Brett Waterman, Joe Moross and Pieter Franken

“We share the radiation measurements with the people,” Franken added. “We show pictures of our devices, we share the design, source code and everything is open. The data is published under a creative commons license that allows anybody to copy it without having to pay money for it. There are no constraints in showing the data and we will share it as soon as we have it, no delays in data release, no restrictions in what we will make public. Complete transparency is our strength.”

Franken lauded the voluntary efforts of the organization.

“This type of crisis brings people together and I come out of my professional life, where typically things take time. People tend to be averse to doing things fast, but in a crisis situation people can get together, team up to get things done very quickly and do something quite exceptional,” the Keio University researcher said. “I find it amazing, working with volunteers where most people have never met each other, but are focused and very professional about getting things done.”

He has his theories about why people are getting involved.

“Because we’re nuts,” he said with a laugh, before getting serious again. “Everyone wants to help out and the people working on it are technically strong and have the skills to do it. Many of us are concerned about our families, want to measure what is happening and share the results with other people.”

Franken, a long-time resident of the Japanese capital, has his own concerns in making sure works.

“On a personal level, because I am able to see with my own eyes what the levels are around me, a lot of fear and anxiety I previously had has gone away,” he said. “This level is manageable for my family and not a reason to abandon ship in Tokyo — I can’t say this for Fukushima — but my position might be different if I had a small child.”

But Franken also concedes’s findings about radiation levels have also posed plenty of questions.

“I had expected that it would have been more uniform, but what we’re finding that it is fairly blotchy,” he said. “You can be OK in one place, but if you walk a couple of meters you find a much higher radiation reading.

“I was hoping to find a simple answer to what is safe or not, but in retrospect, it is much more complex. There is no easy answer to say what level of radiation is too much and how much doesn’t harm you. The truth is somewhere in the middle. But where is that middle? How do you measure safe levels for a person or a group? And, are they really exposed to that level?”


Footnote: An SD Card (Secure Digital Card) is an ultra small flash memory card designed to provide high-capacity memory in a small size. SD cards are used in many small portable devices such as digital video camcorders, digital cameras, handheld computers, audio players and mobile phones.

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2 Responses to Tokyo HackerSpace’s volunteers take ‘people power’ to radiation monitoring

  1. Chiba residence on 07/06/2011 at 12:15 am

    Good job, I am sure those people who are staying in the contaminated areas are scared, you guys give them confidence and hope. I hope you will continue these investigations.

  2. Mitesh on 07/13/2011 at 11:39 pm

    Hello safecast team you are really doing a fantastic job. I am living in Tokyo for last 15 years and my son is going to school in Edogawa ward Tokyo. If I request your team to measure radiation near my son’s school and nearby area , then I will be very grateful to you. is it possible?
    Thank you

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