Nest Protect

Teardown: Nest Protect

We get inside the very latest from Google's Internet of Things subsidiary.

Earlier this year, Google acquired Nest Labs in a $3.2bn deal. The company wants to be the Apple of home automation - it was set up by two ex-Apple engineers. Given its heritage and ownership, it is therefore seen as a barometer for the Internet of Things. But Nest does diverge from the accepted IoT model, as we see in this US version.

Nest has detected that their Internet-connected thermostats have been used in over 100 territories in which they do not market the device. No wonder, then, that Nest recently announced a version for the UK market as well as a continental European version.

According to the company, the international version will be identical but the base that the thermostat attaches to has been completely redesigned for the UK market. This is due to the fact that the UK Nest Thermostat cannot be wired directly to the heating system since it is using lower voltage (12V versus 230V) and would be irreparably damaged if connected that way. It uses a transformer to lower the voltage.

In the US, boilers use a lower voltage - and as a result of this Nest can be directly connected to provide boiler control. The UK and Europe use 120-240V boilers. For these boilers, the company created Heat Link. This connects to the boiler and turns it on and off at the thermostat's (or your) request.

As noted, Nest wants to go the Apple route. Its products offer many IoT-based features while also putting a strong emphasis on industrial design and premium branding. That means that this teardown of the company's Nest Protect smoke alarm, launched in the US last October, must begin with the price.

The cost is $130 for both battery- and mains-operated versions. A typical smoke alarm retails in the US at around $30, and more advanced ones rarely exceed $60. The Nest Protect is therefore about twice as expensive as its nearest rivals.

What does the premium buy you? The Nest Protect initially recalls the Mac Mini, given its flat rectangular exterior with rounded edges and centralised logo. The product doesn't hide its roots, you might say. However, the design here is far from trivial.

Not having a smoke alarm is one thing, but emergency services say another serious problem is that we often put them in the wrong places. Most are ugly, people want their houses to look nice and so these devices are frequently hidden in recesses or behind bookcases and drapes. By looking good on the wall - a better design comparison is to a smart mini speaker - the Nest Protect may be a rare example where the aesthetics could help save lives.

Nevertheless, this is a safety device so functionality is its most important aspect.

As is increasingly standard, the Nest Protect incorporates both a smoke detector - based on a photodiode sensing atmospheric changes to the output from an LED - and a carbon monoxide detector - an electromechanical sensor that analyses the proportion of CO in the air. The clever stuff comes in how it handles the output.

When any of the alarms are triggered, it emits a verbal warning and sends an alert to your mobile device over Wi-Fi. This warning can be along the lines of either, 'There is a possible problem' or, 'Get out of the building now', depending on the reading.

Where multiple alarms are installed, these connect via Zigbee radio, so any one alarm in the house can trigger others and send a message about where the possible emergency is. That is then broadcast by each alarm.

A further interesting feature comes into play if you buy another Nest product, its Learning Thermostat. In this configuration, when one alarm detects CO reaching potentially dangerous levels, it wirelessly instructs the thermostat to shut down the boiler. The IoT is as much about systems communicating with us and other systems as it is about communication within the systems themselves.

One feature that will appeal to those of us that like a fry up is that you can silence the alarm if tripped by some sizzling bangers simply by waving your hands in front of it. No more clambering up and jabbing ineffectively at the case. Straight and angled motion detectors do the job.

Finally, there are photo detectors that allow the Nest Protect's internal light to function as both a status indicator and a night/escape light, plus an 85dB horn in case the voice alert - carried by separate speakers - does not get you moving.

Going inside the Nest Protect reveals a more complex board and electronics than you would normally associate with a smoke detector, as iFixit's Teardown team notes. But while there's undoubtedly some interesting software running, the component focus is on commercial-off-the-shelf (COTS)'parts. This will have helped keep down the bill of materials. So - the Apple link again - there's probably a very good margin for the Nest Protect at its introductory price.

The hardware is designed around what are largely seek-to-protect sensors. "The [CO] detector's measuring circuitry is on the reverse side of the main board, encased in some clear adhesive, which is likely to protect it against shock and the atmosphere," says iFixit.

Overall, the Nest Protect illustrates a lot about where the Internet of Things is going as a market. It follows its own path in that it is an interesting and attractive attempt at differentiation to get beyond what are likely to be very thin margins. Safety devices have long had this inherent attraction.

However, at a more generic level, it operates within a wider context than its own interconnectable system and where cost control has been possible, it seems to have been strongly exercised.

Finally, the iFixit team usually supplies a 'repairability' score for the devices it analyses. But not this time, and with good reason.

If anything like a smoke detector malfunctions, their - and our - advice is that you must either replace it or seek out an authorised repair shop. Don't poke around in there yourself. The Nest Protect well illustrates the point. Its LED and photodiode, for example, are positioned at a precise angle to one another to get the most accurate smoke reading - so you could replace one of those parts and still have a duff smoke alarm if you do not get the position exactly right. 

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