raspberry pi

1707 Articles

3D Printed Prosthesis Reads Your Mind, Sees With Its Hand

July 17, 2019 by 4 Comments

Hobbyist electronics and robotics are getting cheaper and easier to build as time moves on, and one advantage of that is the possibility of affordable prosthetics. A great example is this transhumeral prosthesis from [Duy], his entry for this year’s Hackaday Prize.

Side views of the 3D printed prosthesis arm.With ten degrees of freedom, including individual fingers, two axes for the thumb and enough wrist movement for the hand to wave with, this is already a pretty impressive robotics build in and of itself. The features don’t stop there however. The entire prosthesis is modular and can be used in different configurations, and it’s all 3D printed for ease of customization and manufacturing. Along with the myoelectric sensor which is how these prostheses are usually controlled, [Duy] also designed the hand to be controlled with computer vision and brain-controlled interfaces.

The palm of the hand has a camera embedded in it, and by passing that feed through CV software the hand can recognize and track objects the user moves it close to. This makes it easier to grab onto them, since the different gripping patterns required for each object can be programmed into the Raspberry Pi controlling the actuators. Because the alpha-wave BCI may not offer enough discernment for a full range of movement of each finger, this is where computer aid can help the prosthesis feel more natural to the user.

We’ve seen a fair amount of creative custom prostheses here, like this one which uses AI to allow the user to play music with it, and this one which gives its user a tattoo machine for an appendage.

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Exploring The Raspberry Pi 4 USB-C Issue In-Depth

July 16, 2019 by 117 Comments

It would be fair to say that the Raspberry Pi team hasn’t been without its share of hardware issues, with the Raspberry Pi 2 being camera shy, the Raspberry Pi PoE HAT suffering from a rather embarrassing USB power issue, and now the all-new Raspberry Pi 4 is the first to have USB-C power delivery, but it doesn’t do USB-C very well unless you go for a ‘dumb’ cable.

Join me below for a brief recap of those previous issues, and an in-depth summary of USB-C, the differences between regular and electronically marked (e-marked) cables, and why detection logic might be making your brand-new Raspberry Pi 4 look like an analogue set of headphones to the power delivery hardware.

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Curbing Internet Addiction In A Threatening Manner

July 15, 2019 by 37 Comments

Those who have children of their own might argue that the youth of today are getting far too much internet time. [Nick] decided to put an emergency stop to it and made this ingenious internet kill switch to threaten teenagers with. Rather unassuming on the outside, the big red button instantly kills all network traffic as soon as you push it down, doing its label justice. Reset the toggle button, and the connection is restored, simple as that.

In order to achieve this, [Nick] fit inside the enclosure a Raspberry Pi Zero W, along with a battery and a wireless charging circuit for portability and completely wireless operation. The button is wired into the Pi’s GPIO and triggers a command to the router via SSH over WiFi, where a script listening to the signal tells it to drop the network interfaces talking to the outside world. It’s simple, it’s clean, and you can carry it around with you as a warning for those who dare disobey you. We love it.

Another use for big red buttons we’ve seen in the past is an AC power timer, but you can do just about anything with them if you turn one into an USB device. Check this one in action after the break.

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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.

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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.