Why Not Build Your Quadcopter Around An Evaluation Board?

January 31, 2025 by Lewin Day 3 Comments

Quadcopters are flying machines. Traditionally, that would mean you’d optimize the design for lightweight and minimum drag, and you’d do everything in a neat and tidy fashion. The thing is, brushless motors and lithium batteries are so power-dense that you really needn’t try so hard. A great example of that is this barebones quadcopter build from [hebel23] all the way back in 2015.

The build is based around the STM32F4 Discovery Board, which [hebel23] scored as a giveaway at Electronica in Munich way back when. It’s plopped on top of a bit of prototyping board so it can be hooked up to the four controllers driving the motors at each corner. The frame of the quadcopter similarly uses cheap material, in the form of alloy profiles left over from an old screen door. Other equipment onboard includes a GY-273 electronic compass module, a MPU6050 3-axis gyroscope and accelerometer to keep the thing on the straight and level, and the Fly Sky R9B RC receiver for controlling the thing.

It might look crude, but it gets off the ground just fine. We’ve seen quadcopters using the STM32 in more recent years with more refined designs, but there’s something amusingly elegant about lacing one together with an evaluation board and some protoboard in the middle. If you’re working on your own flying projects, don’t hesitate to notify the tipsline!

Copper Candle Burns Forever… Just Add Fuel

January 30, 2025 by Al Williams 47 Comments

[Zen Garden Oasis] wanted to heat and light a space using a candle. But candles aren’t always convenient since they burn down and, eventually, you must replace them. So he built copper candles using a common copper pipe and an old glass jar. Of course, the candle still takes fuel that you have to replace, but the candle itself doesn’t burn down.

The basic idea is that the copper tube holds a high-temperature carbon wick that stays saturated with fuel. The fuel burns, but the wick material doesn’t. The copper part is actually concentric with a 3/4-inch pipe mostly enclosing a 1/2-inch pipe.

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Inside Vacuum Fluorescent Displays

January 29, 2025 by Al Williams 2 Comments

VFDs — vacuum fluorescent displays — have a distinctive look, and [Anthony Francis-Jones] is generally fascinated with retro displays. So, it makes sense that he’d build a VFD project as an excuse to explain how they work. You can see the video below.

VFDs are almost miniature CRTs. They are very flexible in what they display and can even use color in a limited way. The project [Anthony] uses as an example is an indicator to show the video number he’s currently making.

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A gif of a BlueSky feed, visualized as Matrix-style digital rain.

It’s Raining From The BlueSky

January 28, 2025 by Kristina Panos 15 Comments

Which would you rather feel? The blast of a fire hose, or a cool, digital rain? That’s what we thought. Introducing Blue Rain — the fire hose that is the BlueSky feed, falling semi-cryptically down your screen in Matrix-style letter droplets. Ahh, isn’t that nice?

Now, the rain doesn’t have to be blue. You can change the color, the speed at which it falls, the font, the font size, and other stuff like toggling NSFW, uh, tweets. (Wait, what are we calling BlueSky messages, anyway? Skeets? Really?)

You can even choose between a few fonts for the rain. And if you want to like, actually read one of the skeets, just shoot one carefully with your mouse while it’s still falling.

[Simone] has the project files on GitHub, but you should really read the blog post. Inspired by the lovely firehose3d, [Simone] thought instead of displaying the BlueSky fire hose as digital rain.

First, she collects as many skeets as there are empty columns on a screen from a Jetstream sever. This is calculated based on font style and size. She wrote an algorithm loosely inspired by CodePen, which does digital rain. If the skeet doesn’t fully render by the time it reaches the bottom of the screen, the rest appears at the top of the same column and falls until it’s done displaying. Then the column clears out and waits for a new skeet.

Want to take Matrix-style digital rain on the go? You can cram it onto a Pico, you know.

Thanks for the tip, [FrancisF]!

A Quarter And A Dime Will Get You A Commodore 64 Softmodem

January 20, 2025 by Lewin Day 43 Comments

Back in the 1980s, a viable modem cost hundreds of dollars. Even in the 1990s, you were looking at spending a a Benjamin or two to get computer squawking down the phone lines. According to [Cameron Kaiser], though, it’s possible to whip up a softmodem using a Commodore 64 for much cheaper than that. How much? Just 35 cents, we’re told!

The inspiration was simple—Rockwell apparently used to build modems using the 6502. The Commodore 64 has a 6502 inside, pretty much, so surely it could be a softmodem, right? Indeed, one [John Iannetta] had done this in a one-way form in the 1980s, using the Commodore 64’s SID audio chip to output data in sound form. In 1998, he espoused the 35-cent modem—basically, the price of buying an RCA jack to hook up a phone line to your Commodore 64.

As [Cameron] found out, the concept still works today, as does [John’s] code, but it’s more like 68 cents in 2025 dollars. With the right bits and pieces, and a little code, you can have your C64 modulating data into sound at rates of 300 baud.

It’s hacky, slow, and there’s no real way to receive—the C64 just doesn’t have the chops to demodulate these kinds of signals on its own. You also shouldn’t use it on a real phone line if you don’t want to damage your C64. Still, it’s a wonderful bit of hackery, and it’s fun to see how well it works. We’ve seen some other great Commodore 64 modem projects before, like the ever-useful RetroModem. Meanwhile, if you’ve got your own communication hacks for the computers of yesteryear, don’t hesitate to let us know!

Android Head Unit Gets Volume Knob Upgrade

January 17, 2025 by Lewin Day 22 Comments

Touch screen head units are pretty much the norm these days. Many compromise with annoying on-screen volume controls or tiny buttons. If you find yourself with such a unit, you might like to hack in a real volume knob. [Daniel Ross] shows us how to do just that.

The build uses an ATMega328 as the heart of the operation, though [Daniel] notes an Arduino Uno or Mini would have done just fine. It’s set up with a 74HC14 hex Schmitt trigger, and a CD4066 quad bilateral switch on a custom PCB. As for the volume knob itself, it’s not a real analog pot, instead it’s using a rotary encoder with a center push button. The way it works is that the Arduino reads the encoder, and figures out whether you’re trying to turn the volume up or down based on the direction you’re turning it. It then sends commands to the CD4066 to switch resistors in and out of circuit with lines going to the stereo to emulate the action of volume buttons on the steering wheel.

[Daniel’s] guide explains how everything works in greater detail, and how you can calibrate your head unit to accept these signals while preserving the function of your actual steering wheel volume buttons. Then you just have to find a neat way to integrate the knob into your existing dashboard.

We don’t see as many car stereo hacks in this era when infotainment systems rule all, but we’ve seen some great stuff from older vehicles over the years. Video after the break.

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Head To Head: Servos Vs Steppers

January 14, 2025 by Al Williams 12 Comments

You have a project that needs something to move. Should you use a stepper motor or a servo motor? [Matthias] has an opinion, and you can hear his thoughts in the video below. One tip we’ll take away from the video: when working with motors, shoot some high-frame-rate video and slow it down to see what’s really happening.

The initial tests looked fine at normal speed. But increasing the frame rate and decreasing the playback speed showed some very interesting things like how much each motor was overshooting. The ability to control this sort of thing is a key differentiator for these kinds of motors.

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