If you got an old PC/XT stored somewhere in basement and want to use a newer keyboard, here’s a little project you might like. [Matt] built an AT2XT keyboard adapter on a prototype board using an AT to PS/2 keyboard cable. An AT2XT keyboard adapter basically allows users to attach AT keyboards to XT class computers, since the XT port is electronically incompatible with PC/AT keyboard types. For those retro computing fans with a lot of old PCs, this trick will be great to connect the XT machines to a KVM (keyboard/Video/Mouse) switch.
[Matt] found schematics for the project on the Vintage Computer Federation Forum, but used a PIC12F675 instead of the specified PIC12F629. He does provide the .hex file for his version but unfortunately no code. You could just burn the .hex file or head up to the original forum and grab all files to make your own version. The forum has the schematics, bill of materials, PCB board layout and firmware (source code and .hex), so you just need to shop/scavenge for parts and get busy.
And if you are felling really 31337, you can make a PS/2 version of the binary keyboard to justify the use of your new adapter.
The electric motor is the fundamental building block of almost all robotic projects but, without some form of feedback, it lacks the precise positional control required for the task. Small servos from the modelling world will often use a potentiometer to sense where they are on their travel, while more accomplished motors will employ some form of shaft encoder.
Commercial shaft encoders use magnets and Hall-effect sensors, or optical sensors and encoder discs. But these can be quite expensive, so [Hello1024] hacked together an alternative in an afternoon. It uses another motor as the encoder, taking advantage of the minute changes in inductance as the magnet passes each of its coils. It’s a technique that works better with cheaper motors, as their magnets are more imperfect than those on their expensive cousins.
The sensing is rather clever in its economy, sending a pulse to the motor through an off the shelf motor controller and measuring the time it takes to decay through the body diode of the driving MOSFET. It requires a calibration procedure before first use, and it is stressed that the whole thing is very much still in beta, but it’s a very impressive hack nevertheless. He’s posted a video demonstration which you can see below the break.
After following along with all the Magic Mirror builds, [Troy Denton] finally caved in and started building one for his girlfriend for Christmas. These popular builds are all pretty much bespoke, and this one is no different.
His victim TV didn’t have the ability to be switched on and off by the Raspberry Pi using HDMI/CEC, so he came up with an alternative. He got a couple of opto-isolators and soldered one to the on/off button on the TV’s control board. The Pi didn’t know whether it was switching the TV on or off, it just knew it was switching it. To solve this, [Troy Denton] connected another opto-isolator to the TV’s LED, this one the other way around. When the TV is turned on, the Pi now detects it.
The enclosure is fabbed from 2×4 lumber, the mirror is one-way acrylic which runs somewhere in the $75-100 range for this 27-9/16″x15-1/2″ application. The top and bottom rails include lines of holes to encourage airflow to keep things cool. the face plate is picture framing which makes it easy to mount the mirror. An ultrasonic range finder finishes off the build and when someone stands in front of this magic mirror, the Pi senses it and turns the monitor on.
Included in [Troy]’s post are the Python code and shell scripts he wrote as well as a bunch of pictures of the build process. We’ve seen Magic Mirrors builds before, including some small ones. They’re a cool addition to the house and a fairly simple build.
Controlling the Internet of Things is all about passing information around. Realistically, it doesn’t matter what is used, be it MQTT, HTTP, serial data, whatever, and it doesn’t really matter what data is sent as long as the sender and receiver agree on what the data means. MIDI could be used to pass information back and forth, for example and while MIDI is good for some things, Open Sound Control is a more modern alternative and one area where OSC excels over MIDI is Internet connectivity. [Matt] used OSC to control the lighting he installed in his kitchen.
[Matt] had moved in to a new house and wanted some under-cupboard lighting for his kitchen. He got a few cheap warm white LED lights from the Internet and went about wiring them together. For the controller, an ESP8266-1 was used as well as a 12 volt constant-current buck converter. The software runs on the Sming framework, rather than the Arduino framework, and listens for incoming OSC messages. When it receives a command on a specific channel, a callback function turns the lights on and off. [Matt] also added a switch on the outside of the control box to manually turn the lights on and off.
OSC might not be the right choice for this project, and even [Matt] doesn’t know why he used it, but [Matt] got it working and uses an app on his phone to control it. If he wanted to, he could have used Ableton or another controller to control the lights. (He hasn’t wanted to yet.) OSC is an interesting alternative to MIDI and can also be used with an Arduino without an ethernet shield, or with RFID tags.
There are only a handful of people who can say they’ve built several successful electronic badges for conferences. Voja Antonic is not just on that list, he’s among the leaders in the field. There are a lot of pressures in this type of design challenge: aesthetics, functionality, and of course manufacturability. If you want to know how to make an exposed-PCB product that will be loved by the user, you need to study Voja’s work on the 2016 Hackaday SuperConference Badge. The badge is completely open, with all the design files, firmware, and a manual on the badge project page.
Between travelling from Belgrade to Pasadena and guiding production of 300 badges across the finish line before the conference deadline Voja took ill. He made it to the conference but without a voice he asked me to give his badge design talk for him. You can check that talk out below but let’s touch briefly on why Voja’s design is so spectacular.
The point of a conference badge is for attendees to wear them around their necks. This makes aesthetics as important as any other aspect of the design. Every single person will interact with the badge in this manner.
Voja’s approach was to come up with a series of board outlines and major component placements (in wireframe). He then sought input from many different people to help narrow down a half dozen designs to a single idea. With a design chosen, Voja tweaked the color scheme, ran a batch of prototypes, and started populating boards.
His final refinements are what make the badges so beautiful. He moved from black glossy solder mask to black matte, matched the silk screen color to the color of the auxiliary buttons and the hue of the non-illuminated LEDs. The shape, the component placement (LEDs and buttons on a 45 degree angle) and the choice of edge-mounted battery holders made less bulky with a PCB cut-out are all iconic design elements.
Design has some effect on price (can it be manufactured?) but hardware choices are the biggest driver of this. The badge has three ICs on it, the PIC18F25KL50, an LED driver, and the accelerometer. The rest is fairly straight-forward, an IR receiver, mini-B USB jack, LEDs, buttons, and passives. The point is that there’s nothing truly exotic here. Used well, common components have no trouble creating a device people will love. Sticking within the BOM cost is another issue altogether. We kept it close to our goal, but that’s because a lot of labor from our team didn’t figure into the bottom line. Read more about our tale of manufacturing.
An electronic conference badge is a failure if it only hangs around an attendee’s neck. People need to interact with these badges and for that Voja added a Tetris game, scrolling messages that can can be customized with an IR kiosk at the con, and a gravity simulation using the accelerometer
The underpinnings are a USB bootloader that our friends as Microchip provided. This added USB mass storage support to the badge. Voja wrote a ‘kernel’ that runs in protected bootloader space which takes care of all the low-level hardware handling. This combination makes the badge perfect for all skill levels.
Everything is memory mapped — LEDs control buffer, debounced button reads, RX and TX on the IR bus, accelerometer data subroutine calls, timing, and random numbers. And Voja’s clever implementation throws interrupts to user space first. Most users will redirect this back to the bootloader but seasoned embedded programmers can get full access to the hardware simply by not giving control back to the kernel.
These features are a huge win for the firmware. But Voja wrote a second firmware. He didn’t reveal it until the con had already started. This alternative could be flashed to the badge by the users to take on the crypto challenge.
Voja Antonic is an amazing hardware creator. Looking though his back catalog of projects you will be amazed by his Dali clock and his FR4 enclosures. He sets an example for all to follow — you should be a great hardware engineer, a great designer, and include amazing documentation in your designs. This conference badge hits all of those benchmarks and then some.
If you’ve never set up a telescope in your back yard, you’ve never been truly disappointed. The Hubble can take some great shots of Saturn, nebulae, and other astronomical phenomena, but even an expensive backyard scope produces only smudges. To do astronomy properly, you’ll spend your time huddled over a camera and a computer, stacking images to produce something that almost lives up to your expectations.
At CES, Unistellar introduced a device designed to fit over the eyepiece of a telescope to do all of this for you.
According to the guys at Unistellar, this box contains a small Linux computer, camera, GPS, and an LCD. Once the telescope is set up, the module takes a few pictures of the telescope’s field of view, stacks the images, and overlays the result in the eyepiece. Think of this as ‘live’ astrophotography.
In addition to making Jupiter look less like a Great Red Smudge, the Unistellar module adds augmented reality; it knows where the telescope is pointing and will add a label if you’re looking at any astronomical objects of note.
While I wasn’t able to take a look inside this extremely cool device, the Unistellar guys said they’ll be launching a crowdfunding campaign in the near future.