Author: Zoe Skyforest

3791 Articles

Black And White TV Was Hiding A Special Input Board

July 27, 2021 by 71 Comments

[John Floren] found a nice old black & white TV in a thrift store, and as so many of us would, he decided to take it home. He was surprised upon getting it there that it had, in addition to the VHF and UHF antenna inputs, a mysterious extra connector on the back. Naturally, he set about investigating.

On the rear was an obviously hacked-in F-type connector, paired with a toggle switch, both unlabelled. Running the output of an RF modulator to the connector didn’t net an image on the screen, even though the same method worked when hooked up to the antenna inputs. Undeterred, [John] dug deeper.

Inside, a little PCB bearing the mark “TVM.04” was inside, bearing a handful of components. The device turned out to be a Pickes and Trout TVM-04 adapter, designed in the 1970s for hooking a computer up to a television for use as a monitor. The adapter board allows the Hitachi TV to accept a composite video input. [John] was able to test the TV with a NES clone outputting composite video and voila, it worked! [John] then went further, adding an audio input and installing standard RCA jacks to make it easier to use the input with more modern electronics.

It’s a great example of how simply opening up some electronics and poking around can teach you something. Hacking on old-school TVs is a popular pastime around these parts, it seems. If you’ve been working on your own retro display hack, be sure to let us know.

Building An Electronic Tester For Measuring Arrow Stiffness

July 26, 2021 by 1 Comment

When shooting archery, if you want to be accurate, you need arrows of uniform specification and quality. One important part of this is making sure each arrow has a spine of similar stiffness. Traditionally, this is checked in a very analog way by using weights and measuring deflection of the arrow spine, but it can be done electronically too with this tester from [dvd8n].

The principle of operation is simple. The arrow is held up by two supports, 28 inches apart. The user then presses down in the center of the arrow, deflecting it by a 1/2 inch where itreaches a stop , and load cells at either end of the tester measure the force required to deflect the arrow by the set amount.

It allows arrows to be electronically measured in a fashion that is compatible with existing standards for measurement. The Arduino hardware which measures the load cells can also easily run conversion maths to display the arrow’s measured stiffness in whatever common spine measurement standard is desired. The system can also weigh the arrows, a useful thing to know for the home fletcher.

It’s a tidy build and one that should prove useful when [dvd8n] is building out their next quiver. We’ve seen other capable DIY archery hacks before, too. If you’ve got your own, drop us a line!

 

Little Quadruped Uses Many Servos

July 26, 2021 by 12 Comments

Walking robots were once the purview of major corporations spending huge dollars on research programs. Now, they’re something you can experiment with at home. [Technovation] has been doing just that with his micro quadruped build.

The build runs twelve servos – three per leg – to enable for a great range of movement for each limb. The servos are all controlled by an Arduino Uno fitted with an Arduino Sensor Shield. Everything is fitted together with a 3D printed chassis and limb segments that bolt directly on to the servo output shafts. This is a common way of building quick, easy, lightweight assemblies with servos, and it works great here. Inverse kinematics is used to calculate the required motions of each joint, and the robot can take steps from 1 to 4cm long in a variety of gaits.

We’d love to see a few sensors and a battery pack added on to allow the ‘bot to explore further in an untethered fashion. [Technovation] has left some provision to mount extra hardware, so we look forward to seeing what comes next.

We’ve seen bigger quadrupeds do great things, too. Video after the break.

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A Simple Sun Tracker With Very Few Parts

July 25, 2021 by 60 Comments

There are a huge number of ways to track the sun if you have some reason to do so. You can use time-based algorithms, or feed in coordinates from the Internet, or you could do it with minimal parts and no electronic processing at all. The latter is how this project from [3D Printer Academy] works. 

One key thing about this project is that you shouldn’t be fooled by the solar panels. They’re not here to generate power for external use. Instead, they’re wired up in opposing polarities to a DC gear motor. The motor turns the panel assembly. As one panel is hit by the sun, it turns the assembly to bring the other panel into the sun as well simply by applying a DC voltage to the motor. The other panel is wired up the opposite way, so if it is in the sun, it brings the other panel into alignment as well.

This serves as a very simple planar solar tracker. If you want to track the sun with minimal parts, this is a very easy way to do it. You’ll just need to put whatever you want to actually aim at the sun on top of the assembly. if that happens to be a larger solar panel, it may be cumbersome and another more complex design may be more suitable.

It’s an ingenious and easy way of tracking the sun, even if it’s not immediately apparent how the device would be useful in its current form. If you’ve got an idea how you would use such a mechanism, let us know in the comments.

We’ve seen other solar tracker projects before, too. Video after the break.

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Joker Monitor Keeps An Eye On Hazardous Gas Levels

July 23, 2021 by 12 Comments

The Joker is a popular character in the Batman franchise, and at times uses poisonous gases as part of his criminal repertoire. That inspired this fun project by [kutluhan_aktar], which aims to monitor the level of harmful gases in the air.

The project doesn’t use just one gas sensor, but several! It packs the MQ-2, MQ-3, MQ-4, MQ-6, and MQ-9. This gives it sensitivity to a huge variety of combustible gases, as well as detecting carbon monoxide. The sensors are read by an Arduino Nano, which displays results on an RGB LED as well as an attached IPS screen.

Readings from each sensor can be selected by using an infrared remote. In order to best work as a safety device, however, it could be more useful to have the Arduino automatically cycle through each sensor, checking them periodically and raising an alarm in the event of a high reading.

The whole project is built on a custom PCB which is artfully constructed with an image of the Joker himself. It helps to make the project a bit more of a display piece, and speaks to the aesthetic skills of its creator.

It’s a fun build, and one that could be mighty capable with a few software tweaks. With that said, if you’re working in a space with real hazards from combustible gases, it may be worth investing in some properly rated safety equipment rather than relying on an Arduino project.

Incidentally, if you’d like to improve the results from using such gas sensors, we’ve looked at that in the past. Video after the break.

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A Nerf Ball Turret Complete With FPV

July 23, 2021 by 2 Comments

Sentry turrets have long been a feature of science fiction films and video games. These days, there’s nothing stopping you from building your own. [otjones99] has done just that, with his FPV Nerf Ball launcher.

The system works on the basic principle of launching soft foam balls via a pair of counter-rotating wheels. It’s a remarkably simple way of electrically launching projectiles without a lot of fuss and mucking around, and it works well here. A blower fan is used to gently roll ammunition towards the launcher wheels as required. There’s a hopper-style clip which uses a servo to drop one ball at a time into the launching tube.

An Arduino Uno is responsible for slewing the turret, and handling the firing process. A joystick is fitted with an NRF24L01 radio module to send signals to the Arduino to aim the turret, while an FPV camera mounted on the turret allows the user to remotely see what the turret is aiming at. With a simple pull of the joystick’s trigger, the turret opens fire.

It’s a fun build, and one that shouldn’t do too much damage to anything given the soft pliable nature of the Nerf ammunition. Of course, if you don’t want to aim your turret yourself, you can always go ahead and build yourself an automated sentry gun. Video after the break.

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3D Printed Roller Coaster Looks Pretty Darn Fun

July 23, 2021 by 10 Comments

Rollercoasters are great fun if you can deal with the exhilaration without throwing up or otherwise screaming until you pass out. Of course, the big outdoors ones are a little hard to get to at the moment, what with a pandemic raging outside. However, [3d_coasters] has built a tabletop design that, while it’s too small to ride, is nonetheless quite impressive. (Video, embedded below.)

The coaster is of the launch design. It relies on an elastic cord that is wound up to high tension to launch the train up to speed, with the train then coasting around the rest of the curves on the track. The quality of the modelling is highly impressive, too. The doors at the boarding platform are even actuated to simulate riders boarding the train! Everything is controlled by an Arduino, a handful of micro servos, and a DC motor.

As you might imagine, this project didn’t happen overnight. 600 hours were logged in Fusion 360 developing the track, and slicing the models in Cura for 3D printing took a further 5 hours. The actual printing process itself took 800 hours, not including finishing, so this project certainly isn’t one for the faint of heart. The final model weighs a full 30 lbs.

Believe it or not, we’ve featured 3D printed rollercoasters before, too. Video after the break.

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