Psion Organiser with a Pico memory pack.

Proto-PDA Regains Its Memory With The Help Of A Raspberry Pi Pico

August 26, 2021 by Dan Maloney 2 Comments

Remember the Psion Organiser? If you do, chances are you were an early adopter, as the 8-bit pocket computer had its heyday in the mid-1980s. Things have come a long way since then, of course, but just how far is illustrated nicely by the fact that a Raspberry Pi Pico can stand in for the Psion’s original memory packs.

Like many of the early attempts at putting a computer in your pocket, the Psion II had removable modules, which were dubbed “Datapaks”. The earliest versions of the Datapaks were little more than an EPROM chip on a small PCB, and the technical limitations of the day plus the quirky way of addressing the memory made it possible for [Amen] to mimic a Datapak using a modern microcontroller.

The first version was a breakout board that extended out of the Datapak slot significantly, with a Pico, OLED display, SD card slot, and a bunch of pushbuttons. That prototype proved that the Pico was indeed fast enough to fool the Psion into thinking a legit Datapak was plugged in. [Amen] later refined the design by making a board that stuffs everything into the Datapak slot, with the exception of the OLED which still dangles out where it can be seen. He puts the faux memory to the test in the video below.

It’s great to see groundbreaking tech of yesteryear like the Psion being taken care of and returned to use. We’ve seen others try before; here’s a hack that uses a Pi to connect a Psion Organiser to the internet through its RS-232 serial port.

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How Do You Make A Raspberry Pi On A Stick?

August 24, 2021 by Michael Shaub 38 Comments

We agree with [magic-blue-smoke] that one of the only things more fun than a standard Raspberry Pi 4 is the Compute Module form factor. If they are not destined to be embedded in a system, these need a breakout board to be useful. Each can be customized with a myriad board shapes and ports, and that’s where the real fun starts. We’ve already seen projects that include custom carrier boards in everything from a 3D Printer to a NAS and one that shows we can build a single-sided board at home complete with high-speed ports.

[magic blue smoke] used this ability to customize the breakout board as an opportunity to create a hackable media player “stick” with the Raspberry Pi built-in. We love that this Raspberry Pi CM4 TV Stick eliminates all the adapters and cables usually required to connect a Pi’s fiddly micro HDMI ports to a display and has heat sinks and an IR receiver to boot. Like a consumer media player HDMI stick, all you need to add is power. Continue reading “How Do You Make A Raspberry Pi On A Stick?” →

Dedicated box to play new videos from a handful of content creators.

Dedicated Box Makes YouTube More TV-Like

August 20, 2021 by Kristina Panos 19 Comments

[Exposed Wire] is a huge fan of YouTube and consumes a lot of content. If that sounds familiar, maybe you should build a dedicated YouTube box, too. You get to push buttons, there’s LEDs, and you can take a break from other screens to look at this one for a while. [Exposed Wire] wanted to make it easier to watch the latest videos from their favorite creators, but we would argue that this is more fun, too.

The Rasberry Pi 4 inside checks every five minutes for new videos by keeping track of the creator’s total number of videos in a text file and doing a comparison. If one of the channels has a new video, then the corresponding LED lights up and the new video’s URL is linked to the button. Press the button and the Raspi opens the browser, goes the the URL, maximizes the video, turns off the LED, and updates the video count in the text file.

We like the construction job here. The 1/4″ MDF walls are connected by 3D-printed L-brackets in PETG. At first, [Exposed Wire] mounted the LEDs and buttons to a PCB, but that was really fiddly so they printed panels instead. Combined with the bracket around the screen, the finished build looks good. Check out the build montage after the break.

Regular old YouTube videos not doing it for you anymore? Try watching them at low resolution on an LED matrix.

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Raspberry Pi Powered Standing Desk Rises To New Heights

August 18, 2021 by Matthew Carlson 15 Comments

Like many office workers, [David Kong] found himself the lucky recipient of a motorized sit-stand desk. Also like most office workers with such a desk, he found himself mostly sitting. Reminders on his phone did little to change habits and [David] resolved to automate his desk to rise on a schedule.

Taking off the front panel of the control box required a few screws and [David] was delighted to find some testing pins right on the PCB.By connecting the right pins together, he could simulate any button being pressed. A Toshiba TLP222A solid-state relay made it simple to connect the pins together, the next step was triggering the relay on some sort of timer.

Speaking of timers, the oft-lauded 555 timer was considered. However, the length of time desired wasn’t as well suited for the 555, and the appeal of just tweaking a file to adjust the interval was tempting. Going to the other end of the spectrum, [David] had a Raspberry Pi zero laying around he had been meaning to play with.

After soldering the relay to pin 17 and writing a quick 10 line python script that is executed on startup, [David] had a working solution that could be taped to the underside of the desk, out of sight. Rather than being on a fixed timer, the desk raises every 45 to 60 minutes. The impact on his life has been wonderful, which was the goal of this particular project. It’s been a few months and he hasn’t had to tweak or fix anything. Is a whole 64-bit multicore processor a bit of an overkill for toggling a pin every hour or so? Yes. But we can’t really fault him for reaching for what was already lying around. The results speak for themselves.

Perhaps this would be something you would incorporate when you’re building your own standing desk?

Voice-Controlled Smart Home From The Foundation Up

August 16, 2021 by Bryan Cockfield 20 Comments

Smart homes are becoming an increasingly popular way to automate one’s home, whether it’s turning on lights, closing blinds, or even feeding pets. But the commercial offerings often rely on an internet connection to reach servers in order to work, which invites a lot of privacy concerns for a large percentage of us as well as being inconvenient when the internet is down. Essentially the only way to have a privacy-respecting, self-sufficient smart home is to build one on your own from the ground up, which is exactly what [Xasin] has done with this project.

This build is based on ESP32 modules with a Raspberry Pi as a hub, but it’s not as simple as a MQTT implementation. Not only does the self-contained home automation setup not rely on any outside services, but a failure of the central Pi server will not impact the nodes either as they are configured to continue operating independently even without central control. This allows for a robust home automation implementation without a single point of failure, and also includes some other features that are helpful as well including voice control, all while retaining a core design philosophy that makes it relatively easy to build.

Not only is the build technologically impressive for its standalone capabilities and its elimination of privacy concerns, but [Xasin] also did an excellent job with the physical design as well, adding plenty of RGB and a hexagonal enclosure that gives it a unique look wherever its is placed. If you’re renting right now or otherwise unable to interface any automation with your current home, be sure to take a look at some projects that do home automation without making any permanent changes.

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Using A Laser To Blast Away A Bayer Array

August 9, 2021 by Stephen Ogier 47 Comments

A Bayer array, or Bayer filter, is what lets a digital camera take color photos. It’s an array of tiny color filters that sit on top of a camera’s CCD. The filter makes it so that each sub-pixel in the image sensor only sees red, green, or blue light. The Bayer filter is an elegant tool that gives us color digital photos, but what would you do if you wanted to remove one?

[Les Wright] has devised a way to remove the Bayer filter from the Raspberry Pi Camera. Along with filtering red, green, and blue light for their respective sensors, Bayer filters also greatly reduce the amount of UV and IR light that make it to the CCD sensor. [Les] uses the Raspberry Pi camera in his Pi-based Spectrometer, and he wants to remove the Bayer filter to improve and expand its sensitivity.

Of course, [Les] isn’t the first one to want to do this. Some have succeeded in physically scratching the filter off of the CCD, but because the Pi Camera has vital circuitry around the outside of the sensor, scratching the filter off would likely destroy the circuitry. Others have stripped it off using chemical means, so [Les] gave this a go and destroyed no small number of cameras in his attempt to strip the filter off with solvents like DMSO, brake fluid, and industrial paint stripper.

A look at the CCD, halfway through the process.

Inspired by techniques used in industry, [Les] eventually tried to use a several-kW nitrogen laser to burn off the filter (which seems appropriate given his experience with lasers). He built a rig that raster scans the laser across the sensor using stepper motors to drive micrometer bases. A USB microscope was included to allow progress to be monitored, and you can see a change in the sensor’s appearance as the filter is removed.

After blasting off the Bayer filter, [Les] plugged his improved camera into his home-built spectrometer and pointed it outside. The new camera gives the spectrometer much more uniform sensitivity and allows [Les] to see further into the IR and UV bands. The spectrometer can even detect the Fraunhofer lines—subtle dips in the sun’s spectrum from absorption by molecules in the atmosphere.

This is incredible for a DIY setup and instrument, and we can’t wait to see what [Les] does next to improve his measurements. If your spectrometry needs are more mass than visual, take a look at this home-built mass spectrometer. Home spectrometers aren’t just for examining light spectra—they can also be used to judge the ripeness of fruit!

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SBITX: Hackable HF SDR For The Raspberry Pi

August 6, 2021 by Danie Conradie 32 Comments

Cheap, easy to use SDR dongles are an immensely powerful tool for learning about radio technology. However, building your own SDR is not something too many hackers are confident to tackle. [Ashhar Farhan, VU2ESE] hopes to change this with the sBITX, a hackable HF SDR transceiver designed around the Raspberry Pi.

[Ashhar] introduced the project in talk at the virtual “Four Days In May” annual conference of the QRP Amateur Radio Club International. Watch the full talk in the video after the break. He first goes over the available open source SDR radios, and then delves into his design decisions for the sBITX. One of the primary goals of the project was to lower the barrier of entry. To do this, he chose the Raspberry Pi as base, and wrote C code that that anyone who has done a bit of Arduino programming should be able to understand and modify. The hardware is designed to be as simple as possible. On the receive side, a simple superheterodyne architecture is used to feed a 25 kHz wide slice of RF spectrum to an audio codec, which send the digitized audio to the Raspberry Pi. The signal is then demodulated in software using FFT. For transmit, the signal is generated in software, and then upconverted to the desired RF frequency. [Ashhar] also created a GUI for the 7″ Raspberry Pi screen.

At the moment the sBITX is still in the development stage, information is spread between the video after the break, it’s accompanying PDF, the GitHub repo, and a thread on the BITX20 group.

[Ashar Farhan] is well known in the ham radio community for low cost radio designs like the BITX, and it’s successor, the μBITX. He also created the Antuino, an Arduino based antenna tester. Continue reading “SBITX: Hackable HF SDR For The Raspberry Pi” →