raspberry pi

1648 Articles

Make A Compatible Raspberry Pi Clone – But Your Pi Must Die

July 11, 2019 by 34 Comments

The world is awash with Raspberry Pi clones that boast fruity names, but those looking for a piece of the real thing will find their compatibility only goes so far. Shaky Linux distros abound and, with a few honourable exceptions, they are not for the faint-hearted. The reason that a market hasn’t emerged for fully-compatible clones is that the Pi people seem to have a monopoly on the world’s supply of the particular Broadcom SoCs that they use, forcing would-be competitors to source the brains of their outfit elsewhere.

It’s easy to buy a Raspberry Pi SoC though, if you don’t mind receiving a Raspberry Pi along with it. So to make a compatible Pi clone for space-constrained applications, the folks at Arducam removed the SoC from a Pi 3 and designed a surface-mount module board for it, making a 40 mm x 25 mm postage-stamp style system-on-module. It’s not a Raspberry Pi, but it runs Raspbian.

Their board is not one that they will be selling, but it does open up interesting possibilities for others with an eye to creating Pi boards in different form factors. It would be fascinating for example were somebody to produce an open-source module board for a Pi SoC. Some of you might be asking why the existing Compute Module was not suitable for them; in the write-up they cite mechanical issues with the SODIMM socket.

This isn’t the first compatible Pi clone we’ve seen. Aside from the intriguing but short-lived Odroid W there was another even smaller Arducam offering that never made it to market.

Giving The Pi 4 PCI Express

July 10, 2019 by 71 Comments

The release of the Raspberry Pi 4 brought us a new SoC, up to 4 Gigs of memory, and most importantly, got away from that janky USB to USB and Ethernet solution. The Raspberry Pi 4 has a PCI Express interface buried under some chips, and if you’re very good at soldering you can add a PCIe x1 device to the new best single board computer.

[Thomasz] took a look at the Raspberry Pi 4 and realized the new USB 3.0 chip is attached to the PCI Express interface on the SoC. That is, if you remove this chip and you have some very fine wires, you can patch in a real PCI Express slot. Removing the chip is easy enough with a hot air gun, although a few caps did get messed up. Throw that in an ultrasonic cleaner, and you have a blank canvas to work PCI magic.

This hack requires six wires, or three differential pairs, there’s a reference clock, a lane 0 transmit, and a lane zero receive. Working backwards from a PCI Express riser, [Thomasz] traced out these connections and soldered a few wires in. On the Pi side, a few capacitors were required to be compliant with the PCI Express spec, but the soldering isn’t too bad. You can do a lot with a small tip on an iron and a microscope.

The Pi was successfully wired up to a PCI Express riser card, along with the lines for ground, 5V, link reactivation, and a power good signal. The only thing left to do was to plug in a PCI card and test. This didn’t go as well as expected, because the PCI Express adapter didn’t like being enumerated by the Raspberry Pi kernel. In subsequent experiments, an Adaptec SAS controller worked. Does this mean external graphics cards for the Pi? No, not quite; this is only one lane of PCIe, where modern graphics cards require an x16 slot for the best performance. Still, if you’ve ever wanted a SCSI card for a Pi, this is the best option yet.

Raspberry Pi 4 Benchmarks: Processor And Network Performance Makes It A Real Desktop Contender

July 10, 2019 by 87 Comments

The new Raspberry Pi 4 is out, and slowly they’re working their way from Microcenters and Amazon distribution sites to desktops and workbenches around the world. Before you whip out a fancy new USB C cable and plug those Pis in, it’s worthwhile to know what you’re getting into. The newest Raspberry Pi is blazing fast. Not only that, but because of the new System on Chip, it’s now a viable platform for a cheap homebrew NAS, a streaming server, or anything else that requires a massive amount of bandwidth. This is the Pi of the future.

The Raspberry Pi 4 features a BCM2711B0 System on Chip, a quad-core Cortex-A72 processor clocked at up to 1.5GHz, with up to 4GB of RAM (with hints about an upcoming 8GB version). The previous incarnation of the Pi, the Model 3 B+, used a BCM2837B0 SoC, a quad-core Cortex-A53 clocked at 1.4GHz. Compared to the 3 B+, the Pi 4 isn’t using an ‘efficient’ core, we’re deep into ‘performance’ territory with a larger cache. But what do these figures mean in real-world terms? That’s what we’re here to find out.

Continue reading “Raspberry Pi 4 Benchmarks: Processor And Network Performance Makes It A Real Desktop Contender” →

Fly A Pi On Your Next Model Rocket

July 5, 2019 by 6 Comments

From time to time, we see electronics projects for model rocket instrumentation. Those who have been involved in the hobby for many years may remember when 8-bit microcontrollers like the PIC16F84 were the kind of hardware you might fly on a mission. These days, however, there’s little reason not to send a high-powered processor. This is exactly what [Mohamed Elhariry] has done with his PiX project, which turns a Raspberry Pi Zero W into a neat little flight data recorder.

The hardware has what you might expect from a flight recorder, including accelerometer, gyroscope, and pressure sensor. In addition, it carries temperature and humidity sensors, and of course, a camera. A 64 GB microSD card provides the storage, while a LiPo SHIM board allows the whole thing to run from a 150 mAh battery. All of the components are off-the-shelf breakouts, which makes assembly as easy as soldering a few connections and securing the modules with a little tape.

The project is in GitHub, including python code, schematics for the hardware, and detailed instructions. If you ever wanted to get started with instrumenting a model rocket, this looks like a great resource. Also in the repo is a captured video from an actual flight [34 MB GIF] if you just want to see the view from one launch.

Using commercial modules seems pretty convenient, but if custom hardware is more your thing, check out these 22 mm round PCBs designed to fit inside rockets.

Raspberry Pi Catches The Early Bird

July 4, 2019 by 11 Comments

If you live in an area with high bird activity, setting up a bird feeder and watching some hungry little fellows visit you can be a nice and relaxing pastime. Throw in a Raspberry Pi with some sensors and it can also be the beginning of your next IoT project, as it was the case for [sbkirby] with his Bird Feeder Monitor project.

To track the arrival and departure times of his avian visitors, [sbkirby] attached a set of capacitive touch sensors to each side of his bird feeder, and hooked them up to a Raspberry Pi Zero W via a CAP1188 breakout board. The data is published via MQTT to another Raspberry Pi that serves as backend and stores the data, as well as to an optional additional camera-equipped Pi that will take a picture of each guest along the way. Taking into account that precipitation might affect the sensor readings, he also checks the current weather situation to re-calibrate the sensors if necessary, and also to observe a change in the birds’ presence and eating behavior based on weather conditions.

It seems that sensor-based animal feeding will always serve as inspiration for some new projects, whether feeding the animal itself is the goal, like most recently this fish feeder has shown, or whether the eating behavior is monitored and used for further research such as this squirrel-based weather forecast system.

Exploring Basement Humidity With A Raspberry Pi

July 1, 2019 by 16 Comments

Sometimes a hack isn’t about building something cool. Sometimes it’s more tactical, where the right stuff is cobbled together to gather the information needed to make decisions, or just to document some interesting phenomenon.

Take this impromptu but thorough exploration of basement humidity undertaken by [Matthias Wandel]. Like most people with finished basements in their homes, [Matthias] finds the humidity objectionable enough to warrant removal. But he’s not one to just throw a dehumidifier down there and forget about it. Seeking data on how well the appliance works, [Matthias] wired a DHT22 temperature/humidity sensor to a spare Raspberry Pi to monitor room conditions, and plugged the dehumidifier into a Kill-A-Watt with a Pi camera trained on the display to capture data on electrical usage.

His results were interesting. The appliance does drop the room’s humidity while raising its temperature, a not unexpected result given the way dehumidifiers work. But there was a curious cyclical spike in humidity, corresponding to the appliance’s regular defrost cycle driving moisture back into the room. And when the dehumidifier was turned off, room humidity gradually increased, suggesting an unknown source of water. The likely culprit: moisture seeping up through the concrete slab, or at least it appeared so after a few more experiments. [Matthias] also compared three different dehumidifiers to find the best one. The video below has all the details.

We always appreciate [Matthias]’ meticulous approach to problems like these, and his field expedient instrumentation. He seems to like his creature comforts, too – remember the target-tracking space heater from a few months back?

Continue reading “Exploring Basement Humidity With A Raspberry Pi” →

Building A DIY Desktop-Sized Arcade Machine

June 29, 2019 by 10 Comments

Full-sized arcade cabinets are undeniably cool, but take up a lot of space and can be somewhat of a handful. [PleaseNoFisticuffs] desired something a little more fun-sized, and so built a desktop arcade machine that has some serious style.

It’s a build that’s remarkably accessible for even the inexperienced builder. Paper templates are used to cut out the plywood parts for the cabinet, and the electronic components are all off-the-shelf items. Assembly is readily achievable with high-school level woodworking and soldering skills. Like most similar builds, it relies on the Raspberry Pi running RetroPie, meaning you’ll never run out of games to play.

Where this project really shines, however, is the graphics. Cribbed from Mortal Kombat II and looking resplendent in purple, they’re key to making this cabinet a truly stunning piece. The attention to detail is excellent, too, with the marquee and screen getting acrylic overlays for that classic shine, as well as proper T-moulding being used to finish the edges.

We’d love to have something like this on our desk, though we’d likely get far less work done in such an event. For another take on an arcade build, check out this impressive Undertale pinball cabinet.