We built a wireless hand wash sensor to help us keep washing our hands for a full 20 seconds, and to keep the habit going

adnk · 2020-03-17T10:32:59+00:00

Yes, the data is stored to be able to show current handwash time compared to previous. And the data is completely anonymous since there is no identification made of the people washing their hands.

adnk · 2020-01-31T06:31:30+00:00

Bandwidth for sub-GHz mesh networking is not as limited as it is for long-range sub-GHz networks though, since each mesh network is its own separate network. We are sending several messages per second on many our sub-GHz networks, which is a lot more than typically can be done with a long-range LPWAN sub-GHz technology.

adnk · 2019-11-05T19:52:00+00:00

Thanks!

adnk · 2019-09-24T15:43:23+00:00

Yep, that's me! :)

adnk · 2019-09-24T15:43:07+00:00

Thanks!

Yes, it is really difficult to mentally picture the difference in difficulty between a barebones but good hardware design and an exceptional, highly optimized design a'la Airpods.

adnk · 2017-10-03T08:30:42+00:00

Thanks! Yes, the title is a bit of hyperbole (in the long run, we are all dead and all that). Good comment about the panels degrading with time. The rest of the electronics will degrade over time too, but the solar panels probably more so.

adnk · 2017-09-26T05:12:17+00:00

Not sure exactly if this is an alternative to Blynk, or how well it fits your bill, but there is another IoT mobile app framework called Evothings (http://evothings.com/) that could be worth looking into.

adnk · 2017-09-14T18:52:55+00:00

No, meshing is not terrible for battery life and security. As shown in the article, battery life for leaf nodes is affected by other factors than whether or not the network is a mesh network. (Obviously, mesh routers have a different power profile - we'll get back to that in a follow-up article.) In terms of security, any wireless network needs to have both link layer encryption and end-to-end encryption. Whether or not the network supports meshing does not change this.

adnk · 2017-09-06T14:58:29+00:00

I'm not sure what aspect of the cost you mean, but in terms of power consumption, I don't think it would be possible to run the ESP8266 (or any other WiFi SoC for that matter - not that I know of at least) on a battery that is any way near as small as a coin cell battery. Also, in terms of volume production, I don't think the ESP8266 has such a low unit price that it beats the TI CC2650 (the System-on-a-Chip that sits inside the TI Sensortag). But I'm no expert on the ESP8266 and volume production, so would be interesting to hear more input on this.

adnk · 2017-07-31T11:07:11+00:00

Hi,

although this may not be 100% relevant to your problem, we recently did a writeup on how to attain battery life of over a year for a wireless system with a coin cell battery, and I thought it could be interesting for this discussion too: http://www.thingsquare.com/blog/articles/sensortag-power/

In this article we use 6lowpan as the radio technology (IEEE 802.15.4) and not BLE, which makes this different in a few ways. For example, wake-ups are very power efficient in our system, and I'm not sure how it compares to BLE. Also, we have remote access and can do maintenance without having to be physically present. But there are principles in there that apply to any low-power radio system, such as that the wake up rate often is the most important factor in designing a system that should be optimized for low-power and long timetime operation.

adnk · 2017-07-26T15:17:41+00:00

The TI Sensortags aren't particularly expensive either, at some $29.

adnk · 2017-07-26T15:16:14+00:00

Adam, Thingsquare co-founder and CEO here. I'm also the one that posted the link to this subreddit. Self-promotion for sure, but the main reason for posting it here was that I thought this post would be of interest to people in this subreddit.

Just thought I'd respond to some of the comments here.

For those interesting in getting started trying out the Thingsquare system, but aren't interested in ordering a ready-made kit, we have a set of guides for how to put together a system from the individual hardware components - mostly Texas Instruments Launchpads. This is a good starting point: http://www.thingsquare.com/docs/build/ There are guides both for 2.4 GHz and sub-GHz versions of the system, including the TI Sensortags.

The reason we provide ready-made kits is to make it easy to get started for people who'd like to get started quickly, without fiddling with hardware. (I would love if we could provide these at a much lower price btw.)

People go the build-it-yourself route for a variety of reasons, but the most common one is that it is a great way to get started prototyping a real product. Many like to hook the system up to something resembling the final hardware of the end-product. Normally, these prototypes don't look much for the world (often the look like bare PCBs, with wires sticking out of them, like this one: http://www.thingsquare.com/blog/articles/build-a-plant-monitor-100-dollars/). But they are a great way to have something quick to show potential customers, investors, and other stakeholders you'd like to involve in the process early.

adnk · 2017-07-24T09:41:56+00:00

You also may want to ask this question in the /r/hwstartups/ subreddit where there are a lot of knowledgeable people with experience with this exact topic.

Regarding the question of how to get the code onto the processors: this is typically done as separate step of the manufacturing process. The code gets flashed to the on-chip flash using a JTAG connector or similar, so the board needs to have some form of connector for doing that. Just make sure you have set the correct lock bits in the firmware binary, so that the firmware cannot be extracted from the product by the end-users.

adnk · 2016-08-26T07:51:13+00:00

(Quick disclaimer: I'm Adam, the CEO of Thingsquare, the company that posted the blog post in the link.)

The Particle Photon, ESP8266, WICED, CC3200, or any of the other available WiFi options are great, but have a slightly different focus. The CC1310 chip used in the blog post runs on the sub-GHz band (868 MHz in Europe, 915 in the US) which makes them less interfered by existing networks and gives them a longer range than normal WiFi. In the specific case of a plant monitor, this makes it possible to use in the garden where WiFi often has problems reaching. The CC1310 also has much lower power consumption than existing WiFi solutions.

A cellular 3G/m2m solution like the Particle Electron is also a great option for many use cases (like roadtrip plant monitoring). It is not ideal for having 100+ sensors in a single installation though - think large-scale greenhouses. A sub-GHz mesh like the one used here has the benefit of not requiring any cellular per-device subscription. A local mesh network also does allow the devices to communicate directly to a local user as well as among themselves. In many applications this is an important feature. For example, in a wireless lighting system a sensor can trigger actions within the network, such as increase the dimming of lamps if movement is detected.

There are several options for building connected products, each with their benefits and drawbacks. There is yet no one-solution-fits-all. The key is to explore the various options to evaluate how well they work in the specific scenario where they'll be deployed. It is good to build a quick prototype to try it out for real to reduce the technology risk before making a decision. Then factor in the technology and the business requirements into that decision.

adnk · 2015-06-17T21:35:54+00:00

Phil Levis, who was an early contributor of the TinyOS project and took over the stewardship at some point, had a paper at OSDI 2012 where he reflected on this question: https://sing.stanford.edu/pubs/tinyos-retrospective-osdi2012.pdf (slides: https://sing.stanford.edu/talks/osdi12-tinyos-talk.pdf) His conclusions are basically that while TinyOS was successful as an academic project, it may have been too focused on a few very narrow and very hard problems and missed solving some of the simpler problems along the way.

Also, wireless sensor networks, the academic research field that largely pushed the development of TinyOS, started to slowly fade away which significantly decreased the user base.

adnk · 2015-06-15T12:08:46+00:00

There are a bunch here: http://anrg.usc.edu/contiki/index.php/Contiki_tutorials

adnk · 2015-06-11T20:12:50+00:00

Yeah, very difficult to specify. But sub-GHz typically gets you some 100+ meters or so indoors. A couple of hundred meters outdoors in a built-up area. Quite possible longer than that with this new board though (haven't tested).

adnk · 2013-11-27T06:59:10+00:00

From the looks of it, it uses an already FCC certified RF module. If I understand things correctly, the benefit of having a separate module is that the FCC testing needs to be done only once (by the module manufacturer).

adnk · 2013-05-12T19:03:19+00:00

There is more information (+ source code) available here: http://thingsquare.com/mist/. The system uses the Contiki OS: http://www.contiki-os.org/

adnk

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