raspberry pi

1648 Articles

Alma The Talking Dog Might Win Some Bar Bets

March 16, 2019 by 17 Comments

Students at the University of Illinois at Urbana-Champaign have a brain-computer interface that can measure brainwaves. What did they do with it? They gave it to Alma, a golden labrador, as you can see in the video below. The code and enough info to duplicate the electronics are on GitHub.

Of course, the dog doesn’t directly generate speech. Instead, the circuit watches her brainwaves via an Arduino and feeds the raw data to a Raspberry Pi. A machine learning algorithm determines Alma’s brainwave state and plays prerecorded audio expressing Alma’s thoughts.

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Twelve Channels Of LEDs Give RRRRGGGGBBBB Light

March 12, 2019 by 31 Comments

If you’ve ever searched Mouser or Digikey for LEDs parametrically, you won’t find just one red in your LEDs. You won’t find one green. There is quite literally an entire rainbow of colors of LEDs, and this rainbow goes into infrared and ultraviolet. You can search LEDs by frequency, and an RGEB LED is right at your fingertips. The ‘E’ stands for Emerald, and it’s better than a Bayer filter.

[ayjaym] over on Instructables realized anyone could buy a dozen frequencies of high-power LEDs, and the obvious application for this is to turn it into a tunable light source. The Angstrom is twelve LEDs, all different colors, and all controlled by PWM and piped down a single optical fiber. It’s an RRRRGGGGBBBB LED, ideal for microscopy, forensics, colorimetry, and seeing octoreen.

The heart of this device are twelve 3W star LEDs, with the following wavelengths: 390, 410, 440, 460, 500, 520, 560, 580, 590, 630, 660, and 780 nm. That’s deep red to almost ultra violet, and everything inbetween. These are powered by a 5 V, 60 W power supply, and controlled via a Raspberry Pi with 12 PWM channels in a circuit that’s basically just a bunch of MOSFETs. Proper heatsinking is required.

The impressive part of this build is the optics. A 3D printed mount holds and connects optical fibers and sends them into an optical combiner that is basically just a square acrylic rod. This is output to another optical fiber that will shine on just about anything. A webpage running on a Raspberry Pi sets the PWM channels of all the LEDs, and the resulting output shows up at the end of an optical fiber. It’s great if you want to look at something in a specific frequency of light. It also looks really cool, so that’s a bonus.

Raspberry Pi Camera With Smarts — Cloud Or Local?

March 7, 2019 by 20 Comments

[Mark West] gave an interesting presentation at last year’s GOTO Copenhagen conference. He shows how he took a simple Raspberry Pi Zero webcam and expanded it with AI. He actually added the intelligent features in two different ways: on in the Amazon cloud and another using the Intel Modvidius NCS USB stick directly connected to the USB. You can see the video below.

Local motion detection uses some open source software. You simply configure it using a text file and it even handles the video streaming. However, at that point, you just have a web camera — not amazing, nor very cost effective. However, you get a lot of false alarms with the motion detection software. A random cat walking past, clouds, trees, or even rain would push [Mark] an email and after 250 alert e-mails a day, [Mark] decided to make something better.

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Balena Introduces DIN-Capable Pi Compute Module Carrier Board

March 1, 2019 by 17 Comments

Although you don’t hear about it very much over the clamor of emulating old video game systems, one of the biggest uses of the Raspberry Pi outside its educational roots is in industry. The Pi makes for a great industrial control system, and if you mount it to a DIN rail, you’re golden. This is the biggest reason the Pi foundation is still making the Pi 1, and it’s one of the big motivations behind the Pi Compute Module.

Now that the Pi Compute Module 3 and 3+ have been out for a while, it’s only fitting that these modules get a great carrier board. The balenaFin 1.1 is out now, and it’s the perfect carrier board for the Pi compute module.

Balena (formerly resin.io) is a software stack designed for managing fleets of Linux devices, and there’s no better example of that than a factory filled with Pis fiddling relays and such. Balena has found its way from tracking sea turtles to monitoring oil rigs, and with that comes a need for a developer kit. The Pi compute module is supposed to have a very long support life, so the obvious solution is to make a great carrier board for this fantastic module.

Features of note include two camera connectors, PoE (with a Hat), USB headers, an RGB indicator LED, an industrial temperature range, and a case designed for a DIN rail. So far, so goo, but there’s also a microcontroller with a Bluetooth radio that can operate without the compute module being turned on, and an RTC for time-based operation. There’s a mini PCI express slot designed for cellular modems, and a SIM card slot just for fun.

While most Pi builds we see could make use of these features, they are assuredly one-off builds. You’re not going to be deploying hundreds of Pis if you need to 3D print an enclosure for each one. That’s when actual engineers need to get involved, and if you’re doing that, you might as well go with the Raspberry Pi compute module. If you’re looking for a fleet of Pis, you could do worse than to look at this very nice compute module carrier board.

Leigh Johnson’s Guide To Machine Vision On Raspberry Pi

March 1, 2019 by 9 Comments

We salute hackers who make technology useful for people in emerging markets. Leigh Johnson joined that select group when she accepted the challenge to build portable machine vision units that work offline and can be deployed for under $100 each. For hardware, a Raspberry Pi with camera plus screen can fit under that cost ceiling, and the software to give it sight is the focus of her 2018 Hackaday Superconference presentation. (Video also embedded below.)

The talk is a very concise 13 minutes, so Leigh flies through definitions of basic terms, before quickly naming TensorFlow and Keras as the tools she used. The time she saved here was spent on explaining what convolutional neural networks are and how they work, just enough to prepare the audience. But all of that is really just background, the meat of the talk is self-contained examples that Leigh has put together and made available online. I love to see that since it means you go beyond just watching and try it out for yourself. Continue reading “Leigh Johnson’s Guide To Machine Vision On Raspberry Pi” →

Hack My House: Raspberry Pi As A Touchscreen Thermostat

February 27, 2019 by 49 Comments

Your thermostat is some of the oldest and simplest automation in your home. For years these were one-temperature setting and nothing more. Programmable thermostats brought more control; they’re alarm clocks attached to your furnace. Then Nest came along and added beautiful design and “learning features” that felt like magic compared to the old systems. But we can have a lot more fun. I’m taking my favorite single-board computer, the Raspberry Pi, and naming it keeper of heat (and cool) by building my own touchscreen thermostat.

Mercury thermostats started it all, and were ingenious in their simplicity — a glass capsule containing mercury, attached to a wound bi-metal strip. As the temperature changes, the contraption tilts and the mercury bead moves, making or breaking contact with the wiring. More sophisticated thermostats have replaced the mercury bead with electronics, but the signaling method remains the same, just a simple contact switch.

This makes the thermostat the prime target for an aspiring home automation hacker. I’ve had this particular project in mind for quite some time, and was excited to dive into it with simple raw materials: my Raspberry Pi, a touchscreen, and a mechanical relay board.

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A Modern Solution To Tea Bag Inventory Management

February 20, 2019 by 13 Comments

Britain is famously known as a land of manners and hospitality. Few situations could make an Englishman’s stiff upper lip quiver, short of running out of tea bags while entertaining house guests. Thankfully, [The Gentleman Maker] is here and living up to his name – with a helpful tea monitor to ensure you’re never caught out again.

The Intelli-T, as it has been dubbed, monitors tea inventory by weight. An Arduino Uno combined with a HX711 IC monitors a load cell mounted under a canister, with a reed switch on the lid. Upon the canister being open and closed, the Arduino takes a measurement, determining whether tea stocks have dipped below critical levels. If the situation is dire, a Raspberry Pi connected over the serial port will sound an urgent warning to the occupants of the home. If there is adequate tea, the Raspberry Pi will instead provide a helpful tea fact to further educate the users about the hallowed beverage.

It’s a fun project, and one that has scope for further features, given the power of the Raspberry Pi. A little more work could arrange automatic ordering of more tea online, or send alerts through a service like IFTTT. We’ve seen [The Gentleman Maker]’s uniquely British hacks before, such as the umbrella that tells you the weather. Video after the break.

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