Usually at Hackaday we like to post projects that are of interest because of their complexity. That’s especially true for robots — the more motors and sensors the better. But, occasionally we come across a project that’s beautiful because of its simplicity. That’s the case with [Max.K’s] ZeroBot, recently posted over on Hackaday.io.
The interesting thing about submissions for The Hackaday Prize is seeing unusual projects and concepts that might not otherwise pop up. [ken conrad] has a curious but thoughtfully designed idea for Raspberry Pi-based SmartZoom Imaging that uses a Pi Zero and camera plus some laser emitters to create a device with a very specific capability: a camera that constantly and dynamically resizes the image make the subject appear consistently framed and sized, regardless of its distance from the lens. The idea brings together two separate functions: rangefinding and automated zooming and re-sampling of the camera image.
The Raspberry Pi uses the camera board plus some forward-pointing laser dots as a rangefinder; as long as at least two laser dots are visible on the subject, the distance between the device and the subject can be calculated. The Pi then uses the knowledge of how near or far the subject is to present a final image whose zoom level has been adjusted to match (and offset) the range of the subject from the camera, in effect canceling out the way an object appears larger or smaller based on distance.
We’ve seen visible laser dots as the basis of rangefinding before, but never tied into a zoom function. Doubtlessly, [ken conrad] will update his project with some example applications, but in the meantime we’re left wondering: is there a concrete, practical use case for this unusual device? We have no idea, but we’d certainly have fun trying to find one.
[Jason] has a Sonos home sound system, with a bunch of speakers connected via WiFi. [Jason] also has a universal remote designed and manufactured in a universe where WiFi doesn’t exist. The Sonos can not be controlled via infrared. There’s an obvious problem here, but luckily tiny Linux computers with WiFi cost $10, and IR receivers cost $2. The result is an IR to WiFi bridge to control all those ‘smart’ home audio solutions.
The only thing [Jason] needed to control his Sonos from a universal remote is an IR receiver and a Raspberry Pi Zero W. The circuit is simple – just connect the power and ground of the IR receiver to the Pi, and plug the third pin of the receiver into a GPIO pin. The new, fancy official Raspberry Pi Zero enclosure is perfect for this build, allowing a little IR-transparent piece of epoxy poking out of a hole designed for the Pi camera.
For the software, [Jason] turned to Node JS, and LIRC, a piece of software that decodes IR signals. With the GPIO pin defined, [Jason] set up the driver and used the Sonos HTTP API to send commands to his audio unit. There’s a lot of futzing about with text files for this build, but the results speak for themselves: [Jason] can now use a universal remote with everything in his home stereo now.
There’s something to be said for economies of scale and few things sell more than cell phones. Maybe that’s why [NODE] took inspiration from an iPhone slide out keyboard case to create this Pi Zero W-based portable terminal. This is actually his third iteration, and in the video below he explains why he has built the new version.
By housing the custom bits in a 3D-printed frame that is size compatible with the iPhone, [NODE] manages to leverage the slick slide out keyboard cases available for the phone. The iPhone in question is an older iPhone 5, so the cases are inexpensive, compared to the latest generation. On the other hand, the iPhone 5 is recent enough that it shouldn’t be hard to find a compatible case.
The circuitry itself is pretty straightforward: a battery, a charge controller, and an LCD display. The only complaint we could see was the lack of a control key on the keyboard.
The most popular use for a Raspberry Pi, by far, is video game emulation. We see this in many, many forms from 3D printed Raspberry Pi cases resembling the original Nintendo Entertainment System to 3D printed Raspberry Pi cases resembling Super Nintendos. There’s a lot of variety out there for Raspberry Pi emulation, but [moosepr] is taking it to the next level. He’s building the smallest Pi emulation build we’ve ever seen.
This build is based on the Pi Zero and a 2.2″ (0.56 dm) ili9341 TFT display. This display has a resolution of 240×320 pixels, which is close enough to the resolution of the systems the Pi Zero can emulate. The Pi Zero and display are attached to a beautiful purple breakout board (shared on OSH Park) along with a few 5-way nav switches, a charger for a Lipo battery, and a few other bits and bobs.
Right now, [moosepr] is experimenting with adding sound to his board. It’s easy enough to get sound out of a Pi Zero — it’s just PWM coming from a few pins — but audio also needs an amp, a speaker, and more space on the board. To solve this problem, [moose] found a few piezo transducers from musical greeting cards. These are designed to be thin and as loud as possible, and attaching these directly to the PWM pins providing audio might just work. This is a project to keep an eye on, if only to see if cheap piezos work for low-fi audio in retro emulators.
Putting a complete WiFi subsystems on a single-board computer is no mean feat, and on as compact a board as the Zero W, it’s quite an achievement. The antenna is the tricky part, since there’s only so much you can do with copper traces.
The new Raspberry Pi Zero W’s antenna is pretty innovative, but sometimes you need an external antenna to reach out and touch someone. Luckily, adding an external antenna to the Zero W isn’t that tough at all, as [Brian Dorey] shows us. The Pi Zero W’s designers thoughtfully included solder pads for an ultra-miniature surface-mount UHF jack. The jack pads are placed very close to the long, curving trace that acts as a feedline to the onboard antenna. There’s even a zero ohm SMT resistor that could be repositioned slightly to feed RF to the UHF jack. A little work with a soldering iron and [Brian]’s Pi was connected to an external antenna.
[Brian] includes test data, but aside from a few outliers, the external antenna doesn’t seem to offer a huge advantage, at least under his test conditions. This speaks to the innovative design of the antenna, which [Roger Thornton] from the Raspberry Pi Foundation discussed during last week’s last week’s Hack Chat. Check out the archive for that and more.
Thanks to [theEngineer] for the tip.