Also a question if such harvester need its own power source to be able to operate?

They cite a super wide range of EM freqs from Hz to MHz, and an efficient antenna...

Harvesters don’t need their own power supply and ideally the system can come back to life from totally empty (meaning it doesn’t need to be deployed with any charge level)

I was doing my thing back before the packaged harvester management chips were available and I made a PIC based microcontroller system that could monitor the charge level in a capacitor fed from a piezoelectric vibration energy harvester and decide when to wake up and transmit a data reading based on the capacitors charge level.

The trick was getting the PIC’s sleep current draw low enough that the capacitor was charging even at milli g level vibration levels - from memory you can get a PIC’s sleep current well down in the tens of nano amp range.

PICs have a built in voltage reference that is stable (a zener or schotkey diode from memory of 0.6V?) and a way to read what the Vsupply (basically the capacitor) is compared to it. So the PIC would wake up every 30 seconds, check Vsupply to the built in reference and, when high enough fully wake up, take and transmit a reading and go back to sleep.

From memory I got it running at 50mg transmitting every few minutes.

I got a nice journal publication in IEEE for that work.

So the harvester sustains itself, keeps filling up the bucket, and periodically reports out the progress.

I guess it's a balancing game, as the filling up process is probably slow, so the target's draw needs to be low too.

The main use of energy harvesting is for powering wireless sensor nodes, so this was a simple implementation of that.

https://digital-library.theiet.org/content/journals/10.1049/...

Looks like it was an IET journal, I think my IEEE publications were all conferences.

It used energy-harvesting for the sensor packages, essentially charging caps if things got wet/moved/etc., but would boot up to do the sensor-data processing and communication (BLE/ANT) .. my lead on the project brought his dusty old home phone in, to give us all a stable power source, but we didn't really need it much - lots of 800mhz-900mhz in the city.

Was fun to realize, even back then, that we are literally surrounded by energy and don't really have an energy problem. We have an energy management problem, which we have yet to localize at the individual, and are instead spreading the problem across our society.

But, in between builds on this project, I would often daydream of a scenario where computing devices ran simply on background radiation, and there was no longer any need for cables, really, in order to compute.

Its fun to note we're getting closer and closer to that point. Okay, I could build a solar powered computer and also feel such satisfaction, but .. an all-in-one wafer that simply ran on cosmic noise?

Hell yeah, gimme that, sparkies!!!

(If you want to start a business off this idea feel free to contact me ;) half joking but half serious)

So yeah, I'd rather make musical instruments. If anyone wants to talk about that idea, I'm all in.

:)

Additionally, when doing research around kinetic / thermal energy harvesting technology for a wearable design project (gesture recognizing smart ring) for school, we found modules to have far too low a volumetric energy density (W/mm^3) to be useful, where size matters more than anything else.

Musical instrument design is a well saturated space as well…

Yeah, thats sort of the point. :)

https://www.peterzimon.com/analog-bitcrusher/

https://zynthian.org

Or Mod DUO:

https://mod.audio/mod-duo/

.. can both do what you want, and a ton more to boot - I know you specifically asked for simple and cheap - well, these devices are cheap and .. amazing ..

For example, the Dualo touch uses a slider and a gyroscope for analogical input:

https://dualo.com/en/dualo/

The voice recorded through a mic can also be a nice anological input, such as in the Rc-505 loop station:

https://www.boss.info/global/products/rc-505mk2/

Even better if there is an analogical feedback. For example with springs under buttons, rubber bands attached to finger rings or other crazy ideas.

In what areas of startup’s have you been in? More of electrons or software or something?

I build a system for an agriculture client like this with each node only having a very small solar panel (6in^2) and some super capacitors that kept it reporting data throughout the night. We even used performance metrics from the voltage being output by the solar panel to measure how cloudy it was. These devices reported via LoRa to a base station setup that was connected to a PoE system so we just ran a single Cat-6 STP line to a pole in the middle of the property.

I think the other aspect of “always on” is that the operator isn’t going to pick up the sensor years down the line. They’re just going to leave it dead and buried, especially if the sensors have to live inside the earth There’s ongoing work on harvesting electricity out of soil

That being said, it’s not the energy per se that we can tap into, it’s the gradient created as it dissipates/moves that we tap into. Heat is great, but not if it’s uniform, solar is great, but not if it harvesting it casts an area in shadow that needs it, vibration is great so long as it doesn’t damp and further load the system it’s being taken from.

I believe we are going to find these systems in our future, soon enough.

')

Don't all of these Harvesting systems load a system? For example one of the transmitters somewhere. Yes it is microwatts and no transmitter will notice a single unit. However if we start to talk large quantity of sensors, who is really paying the price? Otherwise we are admitting that Free Energy is a real thing.

You and others may find the recently released Nexperia NBM5100 and NBM7100 of interest. While aimed at batteries it functionally translates high impedance power sources to lower impedance to charge up caps for IoT usage.

https://www.nexperia.com/products/analog-logic-ics/power-ics...

https://www.nexperia.com/products/analog-logic-ics/power-ics...

If it’s a train cart/carriage then not really a problem as there is so much mass and vibration to go around, if it’s the surface of a small industrial machine that needs to be reasonably balanced only producing a few hundred milli g then more of a concern.

Wouldn’t harvesting the stray noise lower the impedance of the thing being noisy, making it use more power to compensate?

I forget the minimum amount but so long as there was more than say 20 mG (milli-gravity) of vibration acceleration then it could harvest from empty.

So really neat to see your system did not suffer from that.

However, the research group I was in was focussed on using silicon carbide devices for hostile environment sensors (think high temp gas sensors primarily) and looking at how to make FETs from SiC that could work in high temp/high radiation environments etc.

This is why my thesis and papers primarily focussed on testing energy harvesting devices at temperature - batteries won't work at 300degC and running power cables up and into a volcano fumarole is a tad awkward.

I had this feeling though that if I didn't get a room temperature, off the shelf components, system working I would have missed a key part of the learning - I just got lucky that the system was novel enough for a paper publication.

I'd love to see an open source energy harvester, especially if it is based on off the shelf components. Low power sensors without a battery would be a major plus for the environment.