Simple Range Testing for LoRa Modules

WiFi and Bluetooth have their use cases, but both have certain demands on things like battery life and authentication that make them unsuitable for a lot of low-power use cases. They’re also quite limited in range. There are other standards out there more suitable for low-power and wide area work, and thankfully, LoRa is one of them. Having created some LoRa pagers, [Moser] decided to head out and test their range.

Now, we’ve done range tests before. Often this involves sending one party out with a radio while the other hangs back at base. Cellphones serve as a communications link while the two parties go back and forth, endlessly asking “Is it working now? Hang on, I’ll take a few steps back — what about now?”

It’s a painful way to do a range test. [Moser]’s method is much simpler; set a cellphone to log GPS position, and have the pager attempt to send the same data back to the base station. Then, go out for a drive, and compare the two traces. This method doesn’t just report straight range, either — it can be used to find good and bad spots for radio reception. It’s great when you live in an area full of radio obstructions where simple distance isn’t the only thing affecting your link.

Build details on the pagers are available, and you can learn more about LoRa here. While you’re at it, check out the LoRa tag for more cool builds and hacks.

Foundry From Scrapped Oven for Cheap, Clean Castings

Home-built foundries are a popular project, and with good reason. Being able to melt and cast metal is a powerful tool, even if it’s “only” aluminum. But the standard fossil-fuel fired foundries that most people build are not without their problems, which is where this quick and clean single-use foundry comes into play.

The typical home foundry for aluminum is basically a refractory container of some kind that can take the heat of a forced-air charcoal or coal fire. But as [Turbo Conquering Mega Eagle] points out, such fuels can lead to carbon contamination of the molten aluminum and imperfections when the metal is cast. With a junked electric range, [Turbo Conquering Mega Eagle] fabricates a foundry that avoids the issue in an incredibly dangerous way. The oven’s heating element is wrapped around an old stainless saucepan, fiberglass bats from the stove insulate the ad hoc crucible, and the range’s power cord is attached directly to the heating element. The video below shows that it does indeed melt aluminum, which is used to sand cast a fairly intricate part.

We can’t see getting more than one use out of this setup, though, so it’s only as sustainable as the number of ranges you can round up. But it’s worth keeping in mind for one-off jobs. For a more permanent installation, check out this portable propane-powered foundry. And to see what you can make with one, check out this engine breather cast from beer cans.

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