38

Check out ESP modules. I've 3 NodeMCU boards running at home checking temperature and humidity, and controlling power sockets and led strips. NodeMCU can be found for about 4-5$. If you want proper support and the chance to change the code from everyplace, take a look at Particle Photon, it's a bit more (about 20$) but works really really nice. If you ...


29

DOORS!!! I don't know if it is in the scope of your question but you can't imagine the wasted energy of opening/closing a door! A French comic strip named Gaston Lagaffe written in 1970 introduced a person who harvested the energy of an opening door to press oranges, print a picture, make coffee,... EDIT, thanks to to Olivier Dulac's comment I was able to ...


18

Solar energy is even indoors an alternative to thermal and vibrational energy harvesting. This indoor photovoltaics use both the natural light and artificial light. On the Feasibility of Indoor Light Energy Harvesting for Wireless Sensor Networks (Carlos Carvalho and Nuno Paulino) discusses indoor light energy harvesting of the attenuated natural ...


18

There is Omega2 from the company Onion. They cost 5$. They are still crowdfunding, therefore I'm not sure about their reliability and I haven't used one.. As @Aurora0001 pointed out, Onion completed their crowdfunding and they managed to pledge a funding 45 times more than their initial goal, which IMO makes them reliable. It has a 580 MHz CPU, 64 MB of ...


15

Wi-Fi outlets are at about 1.5-2 Watts of power consumption, that's the WeMo as mentioned in Jim's answer, and also a few other ones I've tried, like the TP HS110. ZigBee outlets like the one from Samsung SmartThings should use less power due to the ZigBee protocol usage. According to their support forums, it's about 0.3W when the relay is off and 0.6W when ...


15

MQTT has to run over TCP/IP (I can't remember if it's actually in the spec or if just enough assumptions are made to make it so) but its sister protocol MQTT-SN can be run over nearly any protocol that can pass data, I've seen implementations in UDP and serial. Having said that I'm not sure what you gain by running either over BLE, BLE's built in ...


13

As an even cheaper alternative to the NodeMCU from Luis answer I would like to mention the the bare ESP-12E or ESP-12F*, the module that is used on the NodeMCU. They are even cheaper than the NodeMCU, draw less power (because they are lacking the USB converter) and can be powered directly from a 3V battery. You'll need one USB-to-serial converter (3.3V**, ...


13

One that I have been keeping an eye on, but haven't tried yet, is VoCore. It was also crowdfunded like the Omega2. It promises a $4-$18 device, but the ones available start at $17.99. What is relevant about VoCore is that it has fully open source hardware and software. So you can, in theory, get to a low per-unit price at scale. Technical details and source ...


12

To understand better the power consumption of smart plugs it's worth peeking into them. To do so let's see some smart plug reference designs. One from Atmel One from Texas Instruments As you can see the parts of these two different designs are quite the same. There is an AC/DC power supply which provides the DC voltage for the sub-circuits. There is a "...


12

While having so much valuable answers to my question I have also done some further research about the topic. I have found an additional harvesting solution and also a great reference design about a wireless, solar energy powered sensor node, without using a battery. First the additional method from Texas Instruments, which is called RF switch harvesting ...


11

A WeMo Rep stated 1.5 Watts for their wall switch on a WeMo forum. I imagine most of these wall/socket switches will draw 1-2 watts in standby. WeMo Community Thread


10

That's an awesome question! The influence of IoT in power saving wouldn't be that huge, as you've mentioned. But making them smart enough would save a lot of energy. The radio system and the whole automation system would consume only about 5 V @ 1 A (max) if there are no motor drivers and other power components involved (in the case of lights, there are ...


10

There are a variety of encryption methods you could use to secure your traffic, and each one has a slightly different power usage, so I'm going to pick a couple of popular choices. The methodology I use to evaluate each method should be applicable to any other ciphers you find and wish to compare. AES AES is one of the most popular symmetric-key encryption ...


10

Arguably, you'd be better off doing a simple mapping of the data from BLE paradigms to MQTT, rather than trying to literally send MQTT over BLE. BLE generally exchanges data in the form of characteristics. These have various BLE-unique mechanisms for discovering value change that you may find useful. But they have a maximum data length of 20 bytes. It is ...


10

Defining battery life (and perhaps battery size) will tell you how long your thing has to last. That may then lead you to decide to only switch it on when (a) you need to take a reading and (b) when to transmit data. If you only want to wake up say, hourly, then you want something with a Real Time Clock (RTC) or something counting seconds either on board, ...


9

This video from 2015 shows an Aeotec Z-Wave Smart Dimmer measured at: ~0.4W idle ~0.6W on but fully-dimmed (no load) I assume these switches have a similar power usage as an outlet/socket, given their similar functionality. Outlets could be slightly lower, given no need for dimming circuitry. The person writing this post from 2016 purports to work for "a ...


9

This is an idea I've had that I'll throw out here... It seems like it should be possible to have a small device that you simply wrap a mains power cord around a few times (or wrap the device around the power cord, I'm not sure which). When the "host" device is powered on and current is flowing, the "parasite" on the power cord would become powered--not much,...


9

AWS IoT Button The AWS IoT Button is a programmable button based on the Amazon Dash Button hardware. This simple Wi-Fi device is easy to configure and designed for developers to get started with AWS IoT, AWS Lambda, Amazon DynamoDB, Amazon SNS, and many other Amazon Web Services without writing device-specific code. In this article, Ted Benson talks ...


8

Radiators should be a source of vibration (driven from the pump), though you would probably need to investigate the resonance frequencies quite carefully. It is also possible to embed kinetic energy harvesting in switches, although that may not be quite the use case you're imagining. The other side of the equation is determining how much energy you require ...


8

WiFi signals Forget about stealing your neighbor's Wi-Fi to surf the internet. Using cheap everyday materials, researchers at Duke University’s Pratt School of Engineering have developed a remarkable device that can convert microwave signals, like those used to wirelessly transmit the internet, into usable electricity. So in the future, you might instead be ...


8

This is a great idea to harvest energy from our daily energy use. But you have to consider that the energy you harvest comes from somewhere. If you want to harvest some heat from your room heating elements, you must be aware that all the heat converted to electricity via your device will not heat the room. So, your room heater will have to consume more ...


8

The bulk of your power will likely be expended on RF transmission, not CPU cycles spent in encryption routines. Every additional bit transmitted will cost you more power than the encryption you're proposing. That means if you take a naive approach, like using AES in CBC mode, you risk increasing the message size to carry the extra bits in each block. If ...


8

As your most important constraint is having a low power consumption, I think you are already paying attention to the 2 most important parameters: active mode current draw per frequency, and current draw at the different low power modes. Holding the communication as a constant (i.e. same communication protocol and EM frequency), then choosing the best MCU is ...


8

I'll assume that the processing requirements on the device are near enough zero. It sounds like you're using some acceleration input to determine how often to wake up the GSM device. Ideally, you want an MCU which can be triggered from the accelerometer to wake from sleep, and then determine when to send a location ping. Any micro-python based device should ...


7

The ant website has a power estimator which suggests an active 4800 baud connection requires less than 100 uA from a coin cell. I'm not too sure I trust the numbers there though, they look rather optimistic. The page does link some transmit IC data sheets though. According to this digikey article, the energy per bit is similar between ANT+ and BLE, but I ...


7

After some further investigation, I think the issue in the question is that although the power (rate of energy transfer) was reduced, the overall energy consumption was increased by using Docker, so there is no benefit in terms of reduced electricity costs. Based on the paper's figures for 100,000 requests, we can calculate the energy usage through the ...


7

An exercise bike/ treadmill rigged to a dynamo. This will also give you an incentive to work out. Rather than using the microwave oven/convection oven which will eat into their function, you can place a small chimney over the cooking place (though the escaping vapors might pose a problem). I don't exactly know how, but people sit on the couch all day. I ...


7

One often available temperature differential that might be harvested would be: the difference between internal house temperature, and external. With a temperature controlled living environment, there would often be a non-trivial differential, one way or the other. Even without that, external temperature often changes through 24 hrs, whereas we try to ...


7

It is actually possible to allow for sleeping nodes without the need for time synchronization. The basic idea is to send a message multiple times until the node finally wakes up. There is of course a lot of room for clever optimization, so there are hundreds of MAC layer approaches based on this idea. But since your question specifically asks for MAC layers,...


6

Your land line. There is about 48V available on any land line in your house. Lots of bad articles on the internet about this, though this seems to be the best I've seen. Part 68 of the US Federal Communications Commission's telecommunications regulations states that any device that connects to the phone line and is not actively communicating must present ...


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