IoT Telemetry with Energy Harvesting

[sbb1612]

Good Morning,

I'm working in an Energy Harvesting system to power a Wireless Sensor Node, due to low efficiency of the system, I'm able to send temperature measurements every hour (or half hour) and plot it in a Internet Server.
My question is, what would be a real telemetry application where getting data every hour would be considered reasonable?


Thank you

 

[Enny]

The data could be considered reasonable for decision-making though it depends on whatever aim you are trying to achieve however your sensor node should be designed in such a way that data gathered hourly from the sensor network will be capable of performing some processing, gathering sensory information and communicating with other connected nodes in the network to a base station. It will be more clarified if you can explain your ideas about the energy harvesting.

 

[sbb1612]

I harvest energy from the ambient, then charge some capacitors and finally discharge them to read a temperature sensor and send the data to a Monitoring Node to plot them in the web.
Due to the charging time of the capactiors, the data can be sent hourly.

I need to justify why this would be a valid application to IoT Telemetry.

Hope this clarify my question.
Appreciate any help.

 

[BrunoARG]

Hello.

I think that if it can send any information from far away, even at any frequency, it is actually telemetry... It's on you to judge its performance.

I understand your device charges its capacitors (is it a supercapacitor? or a bunch of common electrolytic capacitors in parallel? If not, you should consider supercaps) from the ambient energy. Is it solar? Is it thermal? is it from wind or uses a motor generator maybe? It should be good to know where you get the energy from, since maybe you can generate much more energy than you think, by de fact that you can get pretty little energy from these methods, but it's enough for low power applications such as temperature sensing.

I've worked in low power (battery supplied) devices, and I have to tell you that you must put at least one transistor to supply the external to MCU circuits (sensors, transceivers, LEDs, etc) when you need them, and turning it off when you don't... That will save energy for the MCU to keep working -even at sleep modes- and waking up every an amount of time to do the job. In this case, it could wake every hour, turn the external circuits on (take into account you could have to initialize external transceivers/modules if you turn them off) and measure to transmit data. Meanwhile, you harvest energy and charge your caps.

You've said that you send information every hour or half an hour... Have you thought about taking measurements every -to say- 5 minutes and send a larger data package (with all these measurements) at that hourly rate?

What exact transmission method are you using? ISM bands or GSM/mobile network? Modern transceivers use very little energy and can reach very good ranges, in good conditions (no rain, open areas, plain surface).