Hacker Dictionary: RS-485 Will Go The Distance

RS485 is a communication standard that should be part of the advanced hardware hacker’s arsenal; it’s not commonly encountered, but powerful exactly when you need it. It’s a physical layer interface for wired communications that uses a single differential pair for noise immunity, has good long-distance properties, and allows many connections to a single bus. Because of that, you will encounter it in security systems and even cameras, wired sensor networks, DMX512 lighting and all sorts of industrial electronics. For our hobbyist goals, you can absolutely use RS485 to build your home (or room) automation system, or a relatively large robot – without all those worries that wireless brings.

The name might remind you of RS232, and that’s because both RS232 and RS485 are standards that come from EIA (Electronics Industries Alliance). It also might remind you of RS422, if you’ve ever seen this name mentioned online – RS422 and RS485 are closely intertwined, sharing most of the physical layer, and I’ll show how exactly they relate. Continue reading “Hacker Dictionary: RS-485 Will Go The Distance”

Jetson Nano Robot

[Stevej52] likes to build things you can’t buy, and this Jetson Nano robot falls well within that category. Reading the project details, you might think [Stevej52] drinks too much coffee. But we think he is just excited to have successfully pulled off the Herculean task of integrating over a dozen hardware and software modules. Very briefly, he is running Ubuntu and ROS on the PC and Nano. It is all tied together with Python code, and is using Modbus over IP to solve a problem getting joystick data to the Nano. We like it when existing, standard protocols can be used because it frees the designer to focus more on the application. Modbus has been around for 40 years, has widespread support in many languages and platforms.

This is an ongoing project, and we look forward to seeing more updates and especially more video of it in action like the one found below. With the recent release of a price-reduced Jetson Nano, which we covered last week, this might be an excellent project to take on.

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Meter All The Phases: Three Phase Energy Meter With OpenWrt

Keeping track your overall electricity usage is a good thing, and it’s even better if you know where all the kilowatt-hours are going. [Anurag Chugh’s] house has the three phases coming from the electrical distribution box tidily organized: One for the lighting and fans, one for household appliances, and one for the hot water supply. To monitor and analyze the electrical fingerprint of his house, [Anurag] installed a 3 phase energy meter and hooked it up to the internet.

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