raspberry pi

1657 Articles

3D Printed Server Case Holds 14 Raspberry Pis

December 26, 2020 by 26 Comments

If you ever need to cluster up to 14 Raspberry Pis and an equal number of 2.5 inch hard drives, you might want to look at the Raspberry Pi Server Mark III case from [Ivan Kuleshov]. The original Mark I design came from Thingiverse, but the Mark III is a complete redesign.

The redesign allows for more boards along with a reduction in the number of parts. That takes less plastic and less time to print. The design is also modular, so there should be new components in the future.

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Fox Hunting With Software-Defined Radio

December 26, 2020 by 7 Comments

Fox hunting, or direction finding, is a favorite pastime in the ham radio community where radio operators attempt to triangulate the position of a radio transmission. While it may have required a large amount of expensive equipment in the past, like most ham radio operations the advent of software-defined radio (SDR) has helped revolutionize this aspect of the hobby as well. [Aaron] shows us how to make use of SDR for direction finding using his custom SDR-based Linux distribution called DragonOS.

We have mentioned DragonOS before, but every iteration seems to add new features. This time it includes implementation of a software package called DF-Aggregator. The software (from [ckoval7]), along with the rest of DragonOS, is loaded onto a set of (typically at least three) networked Raspberry Pis. The networked computers can communicate information about the radio waves they receive, and make direction finding another capable feature found in this distribution.

[Aaron] has a few videos showing the process of setting this up and using it, and all of the software is available for attempting something like this on your own. While the future of ham radio as a hobby does remain in doubt, projects like this which bring classic ham activities to the SDR realm really go a long way to reviving it.

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Making Smart Bulbs Smarter With The Power Of MQTT

December 25, 2020 by 14 Comments

What’s the point of smart home automation? To make every day tasks easier, of course! According to [Tomasz Cybulski], that wasn’t the case when he installed IKEA smart lights in his closet. It’s handy to have them in a common switch, in this case a remote control, but having to look for it every time he needed the lights could use some improvement. Enter his project to make smart bulbs smarter, through the use of a simple ESP8266.

While hooking a door switch to the lights’ power supply could provide a quick solution, [Tomasz]’s wife wanted to keep the functionality of the remote control, so he had to look elsewhere. These light bulbs use the simple Zigbee protocol, so arranging for other devices was rather trivial. A USB dongle to interface with the protocol was configured for his existing Raspberry Pi automation controller, while an ESP8266 served as the real-world sensor by connecting it to reed switches installed in the closet doors.

With all the hardware sorted out, it’s a simple matter of making it all talk to each other. The ESP8266, using the Tasmota firmware, sends a signal to an MQTT server running on the Raspberry Pi, which in turn translates it to a remote trigger on the Zigbee frequency with the dongle. The lights turn on when the door opens, and off again once it closes. And since there were no further modifications to the lights themselves, the original IKEA controller still works as expected, which we’re sure [Tomasz]’s wife appreciates!

MQTT can be an interesting piece of software that goes beyond just home automation though, and if you already have a server in your home you can use it to transfer your clipboard’s contents to another device. If you are using it for home automation though, here’s an inspiration for a rather unusual dashboard to keep things interesting. Check out this hack in action after the break.

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Implementing SENT Sensors On The Raspberry Pi

December 22, 2020 by 12 Comments

The SENT protocol, standing for Single Edge Nibble Transmission, is used for sensors that need to send high-resolution data while keeping system costs low. It’s most typically used in the automotive world, where it can be found in such parts as throttle-by-wire pedals and temperature sensors. [Mark Smith] set out to see if he could get the Pi Zero to read such sensors without the use of an intermediate microcontroller.

[Mark]’s initial attempts relied on Python and the RPI.GPIO library. Unfortunately, the overheads introduced made decoding SENT traffic impossible. Undeterred, [Mark] pressed on, leveraging the pigpio library and its callback function which allowed sampling at up to one microsecond. This was fast enough to read the messages from a LX3302A inductive position sensor that uses the protocol.

It’s a project that could prove useful for those trying to work with certain sensors who want to avoid adding complexity to a Raspberry Pi project. Files are available on Github for the curious. We’ve seen other direct sensor builds with the Pi, before too – like this power monitoring system. Video after the break.

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Old Thermostat Gets Smarts

December 19, 2020 by 24 Comments

A smart thermostat is nothing new. But making one built a decade or more ago takes a few tricks. If you want to upgrade your thermostat without replacing it, [geektechniquestudios] shares their solution using a Raspberry Pi Zero to smarten up that dumb controller.

The hardware is decidedly simple: just a Pi Zero and a pair of relays. The relays act as button presses to the old thermostat. The software, though, is decidedly complex. There’s a React server and a Redis database along with some other bits and pieces.

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Pi Compute Module Is Love-child Of Raspberry And Arduino

December 14, 2020 by 27 Comments

The Raspberry Pi compute module is a powerful piece of hardware, especially for the price. With it, you get more IO than a normal Pi, plus the ability to design hardware around it that’s specifically tailored to your needs rather than simply to general-purpose consumers. However, this comes at the cost of needing a way to interface with it since the compute module doesn’t have the normal IO pins or ports, but [Timon] has come up with a handy development board for this module called the Piunora which solves a lot of these prototyping issues.

The development board expands the compute module to the familiar Arduino-like form factor, complete with IO headers, USB ports, and HDMI output. It doesn’t stop there, though. It has an M.2 connector, some built-in LEDs, a camera connector, and a few other features. It also opens up some other possibilities that would be difficult or impossible with a standard Pi 4, such as the ability to run the Pi as a USB gadget rather than as a host device which simplifies certain types of development, which is [Timon]’s intended function.

As a development board, this project has a lot of potential for the niche uses of the compute module when compared to the standard Raspberry Pi. For embedded applications it’s much easier to deploy, with the increased development costs as a tradeoff. If you’re still unsure what to do with the compute module 4, we have some reading for you. And Timon’s previous project is a great springboard.

Still Got Film To Scan? This Lego And Raspberry Pi Scanner Is For You

December 11, 2020 by 9 Comments

There was a time during the early years of mass digital photography, when a film scanner was a common sight. A small box usually connected to a USB port, it had a slot for slides or negatives. In 2020 they’re  a rare breed, but never fear! [Bezineb5] has a solution in the shape of an automated scanner using a Radpberry Pi and a mechanism made of Lego.

The Lego mechanism is a sprocket feeder that moves the film past the field of view from an SLR camera. The software on the Pi runs in a Docker container, and features a machine learning approach to spotting frame boundaries. This is beyond the capabilities of the Pi, so is offloaded to a Google Coral accelerator.

The whole process is automated with the Pi controlling not only the Lego but also the camera, to the extent of retrieving the photos from it to the Pi. There’s a smart web interface to control everything, making the process — if you’ll excuse the pun — a snap. There’s a video of it in action, that you can see below the break.

We’ve featured many film scanner projects over the years, one that remains memorable is this 3D printed lens mount.

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