Introducing the Solarcast Nano

Earlier this year we announced our new Solarcast device. Most notably, this was our first production device to include air quality monitoring capability, but more significant for us was that thanks to Solarcast’s onboard cellular connection and solar power, we now had the ability to “drop and forget” a device, rather than depend on external power infrastructure or manual processes to get data from it. This was a major step  for Safecast and something we knew would find more uses for going forward. A few weeks later a tunnel collapse at the Hanford Site in Washington State presented just the kind of use case we had envisioned. The exciting benefits of Solarcast, however, were counterbalanced by its steep cost and time-consuming production requirements, and while the addition of air quality sensing is something we’ve been working on for a while, it’s not not necessary for quick-deployment radiation survey and monitoring scenarios like at Hanford. Our bGeigie Nano excels at that kind of operation, but it requires someone to physically carry the device around and upload the data. We needed something that combined compact portability and fully automated operation. So we designed it. And sliding in just before the end of the year, we’re excited to introduce the Solarcast Nano.

Sean Bonner triumphantly displays his working Solarcast Nano. (photo Pieter Franken)

 

The Solarcast Nano emerged from our ongoing around the clock discussions of needs and emerging technical  possibilities.  As with the original Solarcast, Ray Ozzie led the design and wrote the software for it. The air quality components in the original Solarcast draw a lot of power, and eliminating them in the Solarcast Nano allowed us to shrink the size of the solar panel, with hopes of fitting it into a smaller pelican case similar to the bGeigie. We brought in Joseph Chiu from ToyBuilder Labs to do the 3d modeling and board design, challenging him to fit everything into a Pelican Case 1040 (double the size of the 1010 case we use for the bGeigie Nano, but considerably smaller than the Solarcast) and meeting a deadline of yesterday.

The Solarcast Nano displays a clear DNA lineage with the bGeigie line.

A quick spec rundown:

  • Drop and forget: Solarcast Nano is compact, wireless, portable, and autonomous. It can easily be deployed anywhere there’s 3G cell service, globally.
  • Self-configuring: Automatically connects with Safecast’s cloud service
  • Low-power consumption: Optimized to provide long, unattended operation under solar / battery power.
  • Radiation: Dual radiation sensors enhance verifiability and help determine isotopes.
  • Rugged: Designed for long-term outdoor use
  • VERY SMALL, easily fits into a backpack.
  • Comms: 3G cellular
  • Position: GPS, with accelerometer that enables it to resample position only when the unit is moved
  • Power: Solar panel, batteries, built-in micro-USB charger, remote cloud-based voltage & current monitoring.
  • Batteries are removable, standard 18650 size, so it can be shipped without issues.
  • Built-in SWD programmer enables “drag & drop” of firmware files without any special software required.
  • Over-the-air update
  • Standard tripod mount
  • Monitor it at anytime using realtime.safecast.org

One of my favorite things about Safecast is coming up with seemingly impossible goals and seeing people blow past them, and that certainly happened here. In October we got to hold the first actual working prototype in our hands, and it exceeded our expectations. It feels wonderful and substantial to hold, looks like a bGeigie, and it does exactly what it’s supposed to. So we decided to push it even further and see if this working prototype could be built as a kit. We tweaked the BOM, fleshed out the documentation, and bought enough parts to build 10. Last week we came together in our Tokyo office with soldering irons in hand, and a healthy dose of motivation and patience, and got to work. By the end of the day, bugs had been squashed and we had 9 working devices (and a broken display disabling the 10th, which was fixed a few days later).

The first batch of Solarcast Nanos are now being tested. Because the sensors themselves are the exact same as those in our Pointcast sensors (which are fixed and require power and internet), the data output is fully compatible. The potential deployment and use cases for these are significant. That said, we haven’t decided yet how many to build, how to pay for them, or how to make them available, but we’re more excited about this new device than we have been about anything else we’ve produced in the past couple of years.

Going back to Hanford, just this month a new release of radioactive material has contaminated several worker’s cars. We’re sending some of these devices there now to get a better idea what is happening in surrounding areas. Hope to have more details on this soon.

Safecast is a non-profit organization powered largely by volunteers. If you’d like to support our efforts with this and other environmental sensors, and open and publicly available dataset, please consider making a recurring donation (via paypal or patreon) which helps us keep things running and putting new sensors out into the field. Financial support from people like you is the only way we’re able to keep this project alive.

Here are some photos from the build event:

Ray flashed the ROMS and tested each unit for successful connectivity and data upload. (photo Sean Bonner)

Fitting this much tech into such a small case requires things to be done in a specific order when building it, as we learned the hard way several times during the day. (photo Pieter Franken)

Pieter holds his completed Solarcast Nano processing module. It’s a bit of a challenge to build… (photo Sean Bonner)

Despite the struggles, Kiki and Yuka both had fun building their kits. (photo Pieter Franken)

Tim Wong partway through his successful build (Photo: Pieter Franken)

Azby found the one with the broken display, but otherwise it worked fine. (photo Pieter Franken)

The Solarcast Nano features a kind of clam shell design that splits the process and power from the sensors, for easy debugging. (photo Azby Brown)

The Solarcast Nano uses 4 different PCBs that are used for structure as well as connectivity. (photo Pieter Franken)

Deployed in Shibuya! (photo Pieter Franken)

About the Author

Sean Bonner

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Sean Bonner is a co-founder and Global Director of Safecast. Based in Tokyo, he's an Associate Professor at Keio University and an Associate Researcher at the Center For Civic Media at the MIT Media Lab.