Batteryless, wireless transmitter (energy harvesting)

Ron Czapala

A friend told me about this " Self-Powered Battery Free Transmitter with Receiver Remote Control"
Acegoo Wireless Lights Switch

A product reviewer said a company named EnOcean developed the technology behind this product (and many similar products):

Energy Harvesting - EnOcean Alliance solutions make use of energy created from slight changes in motion, pressure, light, temperature or vibration. The self-powered wireless sensors help make buildings smarter, safer, more comfortable and more energy-efficient. No batteries - product manufacturers, building professionals and end-users can now realize the promise of battery-less and wire-free control systems. Because they are anchored by self-powered sensors and switches, EnOcean-enabled buildings are more flexible and cost-efficient to design, build and operate.

https://enocean.com/en/technology/energy-harvesting/
https://enocean-alliance.org/en/products/?tx_f03enocean_pi1%5bprodukthauptkategorien%5d=5

Has anyone come across a hobbyist version of this technology? Pretty sure it uses piezoelectricity to supply power...

Heater.

They are using light - Photovoltaic cells.

They are using temperature differences - Peltier effect devices

And whatever else.

The trick then is to have a super efficient power supply to convert whatever you get from the power source to something that can be used to charge a battery/capacitor and power your gadget. Even if only for a short time every day or whatever.

LoRa Wireless technology or even ZigBee will perhaps get you the low power wireless connection.

For sure I have stumbled across hobbyists experimenting with these things. For example:

Ron Czapala

Sparkfun sells an Energy Harvester Breakout board - LTC3588

https://sparkfun.com/products/9946
linear.com/product/LTC3588-1

This breakout board uses the LTC3588 Piezoelectric Energy Harvester from Linear Technologies. This board can be used not only for harvesting piezoelectric energy, but solar energy as well. There is a bridge rectified input for piezo elements (PZ1 and PZ2) and a direct input (VIN) for DC sources. Both are clamped to 20V. In addition, the board can simply be used as a standalone nanopower buck regulator.

An ultralow quiescent current undervoltage lockout (UVLO) mode with a wide hysteresis window allows charge to accumulate on an input capacitor until the buck converter can efficiently transfer a portion of the stored charge to the output. In regulation, the LTC3588 enters a sleep state in which both input and output quiescent currents are minimal. The buck converter turns on and off as needed to maintain regulation.

Four output voltages (1.8V, 2.5V, 3.3V and 3.6V) are pin selectable with up to 100mA of continuous output current and comes pre-configured for an output of 3.3V. However, the output capacitor may be sized to service a higher output current burst. An input protective shunt set at 20V enables greater energy storage for a given amount of input capacitance.

erco

HA! I got this Tomy toy back in the 80's (still have it). The big red dino robot Deadeye is "remote controlled" using Cricket, a small bird. The remote is a piezo clicker, just as found in "electronic" lighters. That burst of energy is fed to a short wire antenna, which functions as a wave shaper. Clicking the remote cycles the toy through several different functions.

It occurred to me back then to use this technology to make a wireless light switch for a lamp. Put a standard-looking switch in the remote clicker and stick on a wall. I tested it and it worked OK. I looked briefly at making it into a commercial product, but the lawyers I showed it to warned that the transmitter generates broad-band interference and was actually illegal in the US. This was originallly a Japanese toy, imported here in small volumes.

Ron Czapala

Digikey has a bunch of wireless switches but they are just a switch - no transmitter or receiver.

They are pretty pricey too!

lardom

One of the ideas I occasionally think about is having a bank of small wind turbines small enough to be turned by a breeze. I'd place them in a grid or stack them somehow and test to see how much current the group could generate.

msrobots

Ron Czapala wrote: »

Digikey has a bunch of wireless switches but they are just a switch - no transmitter or receiver.

They are pretty pricey too!

I am kind of confused.

A wireless switch without transmitter or receiver is just a switch. Like any other switch you can buy without any wires on it.

What am I missing?

Mike

erco

All my switches and components are wireless... until I wire them up.

Don't even ask about my cordless screwdriver.

Beau Schwabe

I contracted with a guy in Dallas, TX shortly after leaving Parallax that was developing "Printable Receivers" based around bow-tie antennas to power LED's from cell-phone and WiFi....( The idea was drink coasters in a bar/restaurant and various labels) There is definitely enough energy there to power a small brain of electronics and re-transmit at a different frequency to do whatever you want if designed correctly. Many moons ago this is supposedly how the Germans used a similar concept to energize wireless "bug transmitters" and make them undetectable when the energy signal was not present ... transmit the necessary energy at one frequency to receive a modulated signal from a microphone at another frequency.

... it's rather amazing how much voltage you can generate across a piece of wire if it is resonating at the right frequency. That is the trick though.

Power transfer test video:

Ron Czapala

msrobots wrote: »

Ron Czapala wrote: »

Digikey has a bunch of wireless switches but they are just a switch - no transmitter or receiver.

They are pretty pricey too!

I am kind of confused.

A wireless switch without transmitter or receiver is just a switch. Like any other switch you can buy without any wires on it.

What am I missing?

Mike

Sorry Mike! I meant to say Digikey has lots of piezo switches... DUH!