Category Archives: low power

Using Backscatter Radio for a Soil Sensor Network

With almost 8 billion souls to feed and a changing climate to deal with, there’s never been a better time to field a meaningful “Internet of Agriculture.” But the expansive fields that make industrial-scale agriculture feasible work against the deployment of sensors and actuators because of a lack of infrastructure to power and connect everything. So a low-power radio network for soil moisture sensors is certainly a welcome development.

We can think of a lot of ways that sensors could be powered in the field. Solar comes to mind, since good exposure to the sun is usually a prerequisite for …read more

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Posted in backscatter, low power, misc hacks, moisture, network, radio hacks, sensor, soil | Leave a comment

Looking Back at QRP Transmitters

When you get to a certain age, you get unsettled by people calling “your” music oldies. That’s how a few of us felt when we saw [Mikrowave1’s] video about Retro QRP – Solid Gold Years (see below). “QRP” is the ham radio term for low power operation, and the “solid gold” years in question are the 1960s to 1980. The videox has some good stuff, including some old books and some analysis of a popular one-transistor design from that time. He even tries a few different period transistors to see which works best.

[Mikrowave1] talks about the construction techniques used …read more

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Posted in amateur radio, arc-5, command receiver, ham radio, low power, QRP, radio hacks, vintage | Leave a comment

Building A LoRa PHY With SDR

The Internet of Things is terrible when it’s your toaster. The real fun happens when you have hundreds or thousands of sensors sending data back to a base station every day. That requires low power, and that means LPWAN, the Low Power Wide Area Network.

There are a lot of options for LPWAN, but few are a perfect fit. LoRa is one of the rare exceptions, offering years of operation on a single AA cell, and range measured in miles. Layers two and three of LoRa are available as public documentation, but until now layer one has been patented and …read more

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Posted in LoRa, low power, LPWAN, sdr, software-defined radio, wireless hacks | Leave a comment

Add Data To Your Shipping Suspicions With This Power-Sipping Datalogger

One only has to ship one or two things via a container, receiving them strangely damaged on the other end, before you start to wonder about your shipper. Did they open this box and sort of stomp around a bit? Did I perhaps accidentally contract a submarine instead of a boat? Did they take a detour past the sun? How could this possibly have melted?

[Jesus Echavarria]‘s friend had similar fears and suspicions about a box he is going to have shipped from Spain to China. So [Jesus] got to work and built this nice datalogger to discover the truth.  …read more

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Posted in data, data logger, logger, low power, misc hacks, pic18, spain | Leave a comment