See if you can talk your local school district into buying a computer that costs about $5,000 and weighs 40 pounds. That was HP’s proposition to schools back in 1968 so really it is more like $35,000 today. The calculator had a CRT display for the RPN stack that you could mirror on a big screen. You could also get a printer or plotter add-on. Pretty hot stuff for the ’60s.
The 1970 videos promoting the HP 9100, posted by the [Computer History Archive Project], shows something we’d think of as a clunky calculator, although by the standards of the day it was a pretty good one with trig functions and a crude programming capability.
While M17 might sound like a new kind of automatic rifle (as actually, it is), we were referring to an open source project to create a ham radio transceiver. Instead of paraphrasing the project’s goals, we’ll simply quote them:
The goal here should be to kick the proprietary protocols off the airwaves, replace DMR, Fusion, D-Star, etc. To do that, it’s not just good enough to be open, it has to be legitimately competitive.
Like some other commercial protocols, M17 uses 4FSK along with error correction. The protocol allows for encryption, streaming, and the encoding of callsigns in messages. There are also provisions for framing IP packets to carry data. The protocol can handle voice and data in a point-to-point or broadcast topology.
Most of us gained a familiarity with siege weapons from Age of Empires, and the march of technology has meant these relics aren’t typically seen on modern battlefields. However, development continues apace in the enthusiast community, and [Tom Stanton]’s latest trebuchet design puts a different spin on launching projectiles at speed.
The design takes advantage of the flywheel as an energy storage device. The flywheel is spun up to speed using a hand crank, through a timing belt and a set of hybrid 3D printed and CNC aluminium gears. Once spun up to sufficient angular velocity, a trigger releases the tennis ball payload from a sling, flinging it forth at speeds over 180 miles per hour.
Moving on from classical materials such as wood and nails, [Tom]’s latest design relies on aluminium in an effort to build something that won’t rot when left outside in the rain. The use of aluminium profiles also makes adjustment and redesigns easy, while providing the necessary adjustments to dial in things like release point and belt tension. We’ve featured a few different designs over the years; the walking-arm trebuchet is perhaps the most oddball of all. Video after the break.
When we see RGB LEDs used in a project, they’re often used more for aesthetic purposes than as a practical source of light. It’s an easy way to throw some color around, but certainly not the sort of thing you’d try to light up anything larger than a desk with. Apparently nobody explained the rules to [Brian Harms] before he built Light[s]well.
Believe it or not, this supersized light installation doesn’t use any exotic hardware you aren’t already familiar with. Fundamentally, what we’re looking at is a WiFi enabled Arduino MKR1000 driving strips of NeoPixel LEDs. It’s just on a far larger scale than we’re used to, with a massive 4 x 8 aluminum extrusion frame suspended over the living room.
Onto that frame, [Brian] has mounted an undulating diffuser made of 74 pieces of laser-cut cardstock. Invoking ideas of waves or clouds, the light looks like its of natural or even biological origin while at the same time having a distinctively otherworldly quality to it.
The effect is even more pronounced when the RGB LEDs kick in, thanks to the smooth transitions between colors. In the video after the break, you can see Light[s]well work its way from bright white to an animated rainbow. As an added touch, he added Alexa voice control through Arduino’s IoT Cloud service.
If we count all the screens in our lives, it takes a hot minute. Some of them are touchscreens, some need a mouse or keyboard, but we are accustomed to all the input devices. Not everyone can use the various methods, like cerebral palsy patients who rely on eye-tracking hardware. Traditionally, that only works on the connected computer, so switching from a chair-mounted screen to a tablet on the desk is not an option. To give folks the ability to control different computers effortlessly [Zack Freedman] is developing a head-mounted eye-tracker that is not tied to one computer. In a way, this is like a KVM switch, but way more futuristic. [Tony Stark] would be proud.
An infrared detector on the headset identifies compatible screens in line of sight and synchs up with its associated HID dongle. A headset-mounted color camera tracks the head position in relation to the screen while an IR camera scans the eye to calculate where the user is focusing. All the technology here is proven, but this new recipe could be a game-changer to anyone who has trouble with the traditional keyboard, mouse, and touchscreen. Maybe QR codes could assist the screen identification and orientation like how a Wii remote and sensor bar work together.
While we’re currently in an era of comparatively low gas prices, the last few decades have seen much volatility in the oil market. This can hit the hip pocket hard, particularly for those driving thirstier vehicles. Thankfully, modifications can help squeeze a few extra miles out of each gallon of dinosaur juice if you know what you’re doing.
The art of striving for the best fuel economy is known as hypermiling, and involves a broad spectrum of tricks and techniques to get the most out of a drop of fuel. Let’s dive in to how you can build a more efficient cruiser for getting around town.
Step 1: Know Thine Enemy
If you want to improve your fuel economy, the first step is to measure it. Without accurate measurement, it’s impossible to quantify any gains made or optimise for the best performance. For those with modern cars, it’s likely that there’s already a trip computer built into the dash. Using this to track your fuel economy is the easiest solution. Instantaneous modes are useful to help improve driving habits, while average modes are great for determining the car’s economy over time.
However, many older vehicles don’t have such features installed as stock. Thankfully, there’s a few ways to work around this. For those driving post-1996 vehicles outfitted with an OBD-II port, tools like Kiwi or Scangauge can often track fuel economy. Failing this, most fuel injected cars can be fitted with a device like the MPGuino that monitors fuel injection to calculate consumption. Fundamentally, all of these tools involve tracking the amount of fuel used per distance travelled. Factory tools and OBD-II gauges do it by using the car’s standard hardware, while the MPGuino splices in to speedometer signals and injector triggers to do the same thing with an Arduino. If you do decide to install a custom device, make sure you calibrate it properly, else your figures won’t bear much resemblance to what’s going on in reality.
Of course, as long as your car has a working odometer and a fuel tank that doesn’t leak, there’s always the pen-and-paper method. Simply reset the trip odometer to zero after filling the tank to the brim. Then, when refilling the tank, fill all the way to the top, and divide the miles driven by the gallons of fuel added back to the tank. This isn’t the most accurate method, as the nature of gas station pumps and automotive fuel tanks mean that tanks aren’t always accurately filled to the brim, due to air pockets and devices used to prevent overfilling. Despite this, it’s a handy way of getting some ballpark figures of your car’s performance over time.
Hackaday editors Mike Szczys and Elliot Williams dish up a hot slice of the week’s hardware hacks. We feature a lot of clocks on Hackaday, but few can compare to the mechanical engineering elegance of the band-saw-blade-based ratcheting clock we swoon over on this week’s show. We’ve found a superb use of a six-pin microcontroller, peek in on tire (or is that tyre) wear particles, and hear the sounds of 500 mph RC gliders. It turns out that 3D printers are the primordial ooze for both pumping water and positioning cameras. This episode comes to a close by getting stressed out over concrete.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!