I’ve had a fairly varied early part of my career in the semiconductors business: a series of events caused me to jump disciplines a little bit, and after one such event, I landed in the test engineering department at Philips Semiconductors. I was tasked with a variety of oddball projects, supporting engineering work, fixing broken ATE equipment, and given a absolute ton of training: Good times! Here’s a story that comes straight off the oddball pile.
We needed to assemble a crack team of experts and high-tail it to deepest darkest Wales, and sort out an urgent production problem. The brief was that the wafer probe yield was disastrous and the correlation wafer was not giving the correct results. Getting to the punch line is going to require some IC fabrication background, but if you like stories about silicon, or red-bearded test engineers, it’s worth it. Continue reading “Hair Today Gone Tomorrow: Four Men Go To Fix A Wafer Prober”→
The two machines are paired using a vintage digital-to-analog logic controller pack. This DAC was originally used to control model trains using your Apple II – something that we now desperately need to see in action. The pack can output voltages between 0 and 2.55 V at 8-bit resolution (or 256 steps), which is plenty for a retro synth.
With the card installed in Slot 7 of the Apple II and the DAC wired through to the synth’s CV/gate, it’s then a trivial matter of writing POKE statements in Applesoft BASIC to control the synth. The video after the break demonstrates playing a simple melody, as well as how one might use the Apple II keyboard to ‘play’ the synth in real time.
If you’re interested in building your own, the video below has all the information needed, as well as helpful advice on where to find a DAC for your preferred model of vintage computer. If all that doesn’t tickle your musical fancy, make sure to check out our coverage on the Game Boy MIDI synth, or perhaps this peculiar synth and visualizer combo.
eVTOL (Electric Vertical Take-off and Landing) craft are some of the more exciting air vehicles being developed lately. They aim to combine the maneuverability and landing benefits of helicopters with the environmental benefits of electric drive, and are often touted as the only way air taxis could ever be practical. The aircraft from Joby Aviation are some of the most advanced in this space, and [Peter Ryseck] set about building a radio-controlled model that flies in the same way.
The design is inspired by the Joby eVTOL test vehicle.
The result is mighty complex, with six tilt rotors controlled via servos for the utmost in maneuverability. These allow the vehicle to take off vertically, while allowing the rotors to tilt horizontally for better efficiency in forward flight, as seen on the Bell-Boeing V-22 Osprey.
The build uses a 3D-printed chassis which made implementing all the tilt rotor mounts and mechanisms as straightforward as possible. A Teensy flight controller is responsible for controlling the craft, running the dRehmFlight VTOL firmware. The assembled craft only weighs 320 grams including battery; an impressive achievement given the extra motors and servos used relative to a regular quadcopter build.
With some tuning, hovering flight proved relatively easy to achieve. The inner four motors are used like a traditional quadcopter in this mode, constantly varying RPM to keep the craft stable. The outer two motors are then pivoted as needed for additional control authority.
In forward flight, pitch is controlled by adjusting the angle of the central four motors. Roll is achieved by tilting the rotors on either side of the plane’s central axis, and yaw control is provided by differential thrust. In the transitional period between modes, simple interpolation is used between both modes until transition is complete.
Outdoor flight testing showed the vehicle is readily capable of graceful forward flight much like a conventional fixed wing plane. In the hover mode, it just looks like any other multirotor. Overall, it’s a great demonstration of what it takes to build a successful tilt rotor craft.
Many readers will be familiar with the Dyson Air Multiplier, an ingenious bladeless fan design in which a compressor pushes jets of air from the inside edge of a large ring. This fast-moving air draws the surrounding air through the ring, giving the effect of a large conventional fan without any visible moving parts and in a small package. It’s left to [Integza] to take this idea and see it as the compressor for a jet engine, and though the prototype you see in the video below is fragile and prone to melting, it shows some promise.
His design copies the layout of a Dyson with the compressor underneath the ring, with a gas injector and igniter immediately above it. The burning gas-air mixture passes through the jets and draws the extra air through the ring, eventually forming a roaring jet engine flame exhaust behind it. Unfortunately the choice of 3D print for the prototype leads to very short run times before melting, but it’s possible to see it working during that brief window. Future work will involve a non-combustible construction, but his early efforts were unsatisfactory.
It’s clear that he hasn’t created the equivalent of a conventional turbojet. Since it appears that its operation happens when the flame has passed into the center of the ring, it has more in common with a ramjet that gains its required air velocity with the help of extra energy from an external compressor. Whether he’s created an interesting toy or a useful idea remains to be answered, but it’s certainly an entertaining video to watch.
For the Nintendo aficionados of the 90s, the Super Game Boy was a must-have cartridge for the Super Nintendo which allowed gamers to play Game Boy games on your TV. Not only did it allow four-color dot-matrix gaming on the big screen, but it let you play those favorite Game Boy titles without spending a fortune on AA batteries. While later handhelds like the PSP or even Nintendo Switch are able to output video directly to TVs without issue, the original Game Boy needed processing help from an SNES or, as [Andy West] shows us, it can also get that help from a modern microcontroller.
Testing the design before installing it in the NES case.
The extra processing power in this case comes from a Raspberry Pi Pico which is small enough to easily fit inside of a donor NES case and also powerful enough to handle the VGA directly. For video data input, the Pico is connected to the video pins on the Game Boy’s main board through a level shifter. The main board is also connected to a second Pico which handles the controller input from an NES controller. Some fancy conversion needed to be done at this point because although the controller layouts are very similar, they are handles by the respective consoles completely differently.
With all of the technical work largely out of the way, [Andy] was able to put the finishing touches on the build. These included making sure the power buttons, status LEDs, and reset button all functioned, and restoring the NES case complete with some custom “Game Guy” graphics to match the original design of the Game Boy. We commend the use of original Game Boy hardware in this build as well, which even made it possible for [Andy] and his wife to play a head-to-head game of Dr. Mario through a link cable with another Game Boy. If you’re looking for a simpler way of playing on original hardware without burning a hole in your wallet buying AA batteries, take a look at this Game Boy restoration which uses a Lithium battery instead.
Who can’t resist snapping up a piece of really expensive laboratory testing gear for next to nothing when browsing eBay or similar? Maybe it’s giving you mournful eyes when browsing through a yard sale. Often such gear is sold for cheap because it’s defective, but with a bit of attention, can be brought back to life. This is how [Roberto Barrios] ended up with a Rohde & Schwarz FSIQ 7 signal analyzer lounging around his place for a few months until he got it fixed.
See anything wrong with this picture?
Part of the fix was replacing a busted RF converter module (A160 IF-Filter) with a used-but-working replacement, but this left the device with odd calibration failures. In the process of tracing down the cause, [Roberto] took many high-resolution images of both sides of the PCBs in order to reverse-engineer the circuit. To complicate matters, the calibration results indicated that the unit’s filters were fine on boot-up, but would deviate after a few minutes.
After extending the filter module to work outside the enclosure and experimental use of a hot air gun, ultimately the cause was tracked down to an unsoldered pad. Considering the extremely simple cause of the failure, it would seem that R&S QA had an off-day when that replacement module was produced. If there’s a lesson to be learned here it is probably that a simple visual inspection is sometimes all that is needed to fix a hardware issue.
Have you ever looked at a derelict electric wheelchair and thought “I bet I could make something great with that!” Of course you have- this is Hackaday, after all! And so did [Made in Poland], who managed to get a hold of a broken down electric wheelchair and put the full utility of his well equipped metalworking shop to work. The results? Lets just say it hauls.
What we really enjoyed about the build was that there wasn’t much that couldn’t be done by an average garage hacker with a drill press, angle grinder, and a stick welder. While it’s definitely nicer to have a lathe and a high quality welding table, plasma cutter, and everything in between, nothing that [Made in Poland] did in the video is such high precision that it would require those extensive tools. There may be some parts that would be a lot more difficult, or lower precision, but still functional.
Another aspect of the build is of course the control circuitry and user interface. Keeping the skid steer and castor approach meant that each motor would need to be controllable independently. To achieve this, [Made in Poland] put together a purely electromechanical drive controlled with momentary rocker switches and automotive relays to form a simple H-Bridge for each motor.
Of course you just have to watch until the end, because it really proves that a man will do anything to get out of hauling wood around! Old electric wheelchairs can also make a great base for big robots, as it turns out.
