College Gives You Practical Electronics

September 3, 2024 by Al Williams 28 Comments

While classroom learning isn’t for everyone, one awesome benefit of the Internet is that you have a variety of college classes available to you, even if they aren’t for credit. You can virtually audit classes from institutions around the world on just about any topic you can think of. Of course, the topic we think of is practical electronics and that happens to be the title of a class from [Dr. Bill Newhall] of the University of Colorado. You can watch the first part in the video below. So far, there are two lectures available but more are coming as the class is ongoing right now.

[Dr. Newhall] is one of us. He’s a ham radio operator and a pilot, as well as an electrical engineer. This class is aimed at others who need to understand electronics in another context. It reminded us of the genesis of one of our favorite books — also from a professor — The Art of Electronics.

The course material promises to cover topics ranging from solar and battery power sources, power conversions, IoT and RF communications, sensors, and DC motor control. Of course, there will also be sections on microcontrollers and associated hardware.

Just like a real class, the first lecture has a lot of housekeeping information, but you might want to skim it anyway. But if you want to get to the electronics, the second video won’t disappoint. While it covers a lot of ground that is probably familiar to most Hackaday readers, it is a good review and there’s more coming in the future lectures.

With all the resources online, you can easily hack your own degree plan together. Having access to instructors like [Dr. Newhall] is exactly the point we were making about how the Internet allows you to leverage the best educational opportunities no matter where you are.

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An Open Source 6kW GaN Motor Controller

August 19, 2024 by Dave Rowntree 30 Comments

We don’t know how you feel when designing hardware, but we get uncomfortable at the extremes. High voltage or current, low noise figures, or extreme frequencies make us nervous. [Orion Serup] from CrabLabs has been turning up a few of those variables and has created a fairly beefy 3-phase motor driver using GaN technology that can operate up to 80V at 70A. GaN semiconductors are a newer technology that enables greater power handling in smaller packages than seems possible, thanks to high electron mobility and thermal conductivity in the material compared to silicon.

The KiCAD schematic shows a typical high-power driver configuration, broken down into a gate pre-driver, the driver itself, and the following current and voltage sense sub-circuits. As is typical with high-power drivers, these operate in a half-bridge configuration with identical N-channel GaN transistors (specifically part EPC2361) driven by dedicated gate drivers (that’s the pre-driver bit) to feed enough current into the device to enable it to switch quickly and reliably.

The design uses the LM1025 low-side driver chip for this task, as you’d be hard-pushed to drive a GaN transistor with discrete components! You may be surprised that the half-bridge driver uses a pair of N-channel devices, not a symmetric P and N arrangement, as you might use to drive a low-power DC motor. This is simply because, at these power levels, P-channel devices are a rarity.

Why are P-channel devices rare? N-channel devices utilise electrons as the majority charge carrier, but P-channel devices utilise holes, and the mobility of holes in GaN is very low compared to that of electrons, resulting in much worse ON-resistance in a P-channel and, as a consequence, limited performance. That’s why you rarely see P-channel devices in a circuit like this.

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Audio On Pi: Here Are Your Options

August 12, 2024 by Arya Voronova 36 Comments

There are a ton of fun Raspberry Pi and Linux projects that require audio output – music players, talking robots, game consoles and arcades, intelligent assistants, mesh network walkie-talkies, and much more! There’s no shortage of Pi-based iPods out there, and my humble opinion is that we still could use more of them.

To help you in figuring out your projects, let’s talk about all the ways you can use to get audio out of a Pi or a similar SBC. Not all of them are immediately obvious and you ought to know the ropes before you implement one of them and get unpleasantly surprised by a problem you didn’t foresee. I can count at least five ways, and they don’t even include a GPIO-connected buzzer!

Let’s rank the different audio output methods, zoning in on things like their power consumption, and sort them by ease of implementation, and we’ll talk a bit about audio input options while we’re at it.

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A Demo Party On A Chip

July 28, 2024 by Jenny List 5 Comments

The demoscene has provided our community with its artistic outlet since the first computers which could handle graphics, and has stayed at the forefront of technology all the way. For all that though, there’s a frontier it hasn’t yet entirely conquered, which exists in the realm of silicon. To address this cones the ever awesome Tiny Tapeout, who are bringing their ASIC-for-the-masses scheme to the world of demos with an ASIC demo competition.

With a closing date of 6th of September, all accepted entrants get a free Tiny Tapeout tile for their entry. Entries are limited to two tiles or less. with VGA and audio outputs via a specified PMOD pinout. There are a variety of categories including the expected best sound and best graphics, but among them we’re most interested by the mixed signal one that includes analogue circuitry.

Tiny Tapeout has been a particularly exciting project over the last couple of years, truly breaking new ground for the hardware hacker world. Since they’ve just recently been able to start doing some analog design on the chips, we’re excited to see what people come up with for this competition, and we hope it will provide significant advancement to the art. In the best tradition of the demo scene, they’ve even made an intro for the competition, which you can see below the break.

Want to know what all the fuss is about? Start here!

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The BAPPR Keeps Your Addressable LED System Cool

July 27, 2024 by Alexander Rowsell 17 Comments

We all love a nice strip or grid of addressable LEDs. It can add flair or an artistic touch to many projects, and it can make gaming computers look extra 1337. However, providing enough current to a long strip of addressable LEDs can sometimes be difficult. Often a separate voltage rail is needed to supply enough juice. At the same time, continually sending out data to animate them can often use 100% of the microcontroller’s CPU power, especially if the serial bus is being bit-banged. A crash or badly timed interrupt can leave the system in a weird state and sometimes with the LEDs not displaying the correct colours. Or you might just want to enter a power-saving mode from time to time on your main MCU? Well, the BAPPR is designed to address all of these problems.

[TheMariday] created the BAPPR and made it fully open-source. It’s a switch-mode power supply that can accept anywhere from 7 V to 17 V and converts it into a strong 5 V rail for typical addressable LEDs. It also has a “smart” mode where it monitors the data line going to the LEDs to see if there is activity. If for some reason the system stops sending data, the BAPPR can intervene and shut off the power to the LEDs, which can help prevent strange colour combinations from being displayed while the system recovers. Once data starts flowing again, power is restored and the light party can resume.

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OSHW Model Rocket Kit Embraces The Hexagon

July 27, 2024 by Tom Nardi 19 Comments

If you’ve ever built a model rocket, you’ll know there’s not a whole lot to them. Essentially it’s a cardboard tube, a plastic nosecone, some fins, and a little clip that will keep it riding the launch rail as it accelerates off the pad. Extra points awarded if you add in a parachute, but strictly speaking, even that’s a luxury. Stick an Estes motor in that thing and send it.

But pointing out that lightweight cardboard tubes can be tricky to ship without getting crushed, [Concrete Dog] has come up with HEXA, a clever model rocket kit that uses pre-scored cardstock instead. The immediate advantage is that this allows the rocket to be shipped as flat sheets of material, but as a secondary bonus, once folded into its final shape the rocket has an awesome hexagonal cross section.

As with a traditional kit, both the nosecone and fins are plastic. Except here they’ve been 3D printed in either PLA or PETG depending on their proximity to he hot and fiery area of the rocket. [Concrete Dog] says the printed parts are largely ready to fly as-is, but that some quality time with a piece of sandpaper and a coat of paint could improve the aerodynamics a bit if you were so inclined.

Ready for the best part? [Concrete Dog] has decided to release all of the design files for the rocket under the CERN Open Hardware Licence, meaning you’re free to reproduce and modify the rocket as you see fit. In fact, on July 24th, the HEXA rocket was officially certified as Open Hardware by the Open Source Hardware Association (OSHWA) — a first for a DIY rocket, as far as we can tell.

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Modern In-Circuit Emulator For The 6809

July 19, 2024 by Alexander Rowsell 12 Comments

The Motorola 6809, released in 1978, was the follow-up to their 6800 from four years earlier. It’s a powerful little chip with many 16-bit features, although it’s an 8-bit micro at heart. Despite its great improvements over the 6800, and even technical superiority over the Z80 and 6502 (hardware multiply, for example!), it never reached the same levels of success that those chips did. However, there are still some famous systems, such as the TRS-80 Colour Computer, which utilized the chip and are still being hacked on today. [Ted] is clearly a fan of the 6809, as he used a Teensy 4.1 to create a cycle-exact, drop-in 6809 emulator!

A small interposer board rearranges the Teensy pinout to match the 6809, as well as translating voltage levels from 3.3V to 5V. With careful design, the Teensy matches the cycle diagrams in the Motorola datasheet precisely, and so should be able to run any applications written for the chip! A great test was booting Extended Colour BASIC for the TRS-80 CoCo 2 and running some test BASIC programs. Any issues with opcode decoding or timing would certainly be exposed while running an interpreted language like BASIC. After this successful test, it was time to let the Teensy’s ARM Cortex-M7 rip and see what it could do.

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