A High Resolution ADC From Scratch

October 4, 2025 by 6 Comments

It’s a well-known conundrum that while most computers these days are digital in nature, almost nothing in nature is. Most things we encounter in the real world, whether it’s temperature, time, sound, pressure, or any other measurable phenomenon comes to us in analog form. To convert these signals to something understandable by a digital converter we need an analog-to-digital converter or ADC, and [Igor] has built a unique one from scratch called a delta sigma converter.

What separates delta sigma converters apart is their high sampling rate combined with a clever way of averaging the measurements to get a very precise final value. In [Igor]’s version this average is provided by an op-amp that integrates the input signal and a feedback signal, allowing for an extremely precise digital value to be outputted at the end of the conversion process. [Igor] has built this one from scratch as well, and is using it to interface a magnetic rotary encoder to control digital audio playback.

Although he has this set up with specific hardware, he has enough detail in his video (including timing diagrams and explanations of all of the theory behind these circuits) for anyone else to build one of these for other means, and it should be easily adaptable for plenty of uses. There are plenty of different ADC topologies too, and we saw many different ones a few years ago during our op-amp challenge.

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How Your SID May Not Be As Tuneful As You’d Like

October 4, 2025 by 6 Comments

The MOS Technologies 6581, or SID, is perhaps the integrated circuit whose sound is most sought-after in the chiptune world. Its three voices and mix of waveforms define so much of our collective memories of 1980s computing culture, so it’s no surprise that modern musicians seek out SID synthesisers of their own. One of these is the MIDISID, produced by [MIDI IN],  and in a recent video she investigates an unexpected tuning problem.

It started when she received customer reports of SIDs that were out of tune, and in the video she delves deeply into the subject. The original SID gained its timing from a clock signal provided by the Commodore 64, with thus different timing between NTSC and PAL versions of the machine. This meant European SID music needed different software values to American compositions, and along the way she reveals a localisation error in that the British Commodore 64 manual had the wrong table of values.

Modern SIDs are emulated unless you happen to have an original, and her problem came when switching from one emulated SID to another. The first one used that clock pin while the second has its own clock, resulting in some music being off-tune. It’s a straightforward firmware fix for her, but an interesting dive into how these chips worked for the rest of us.

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Building A Ham Radio Data Transceiver On The Cheap

October 3, 2025 by 15 Comments

Once upon a time, ham radio was all about CW and voice transmissions and little else. These days, the hobby is altogether richer, with a wide range of fancy digital data modes to play with. [KM6LYW Radio] has been tinkering in this space, and whipped up a compact ham radio data rig that you can build for well under $100.

Radio-wise, the build starts with the Baofeng UV-5R handheld radio. It’s a compact VHF/UHF transceiver with 5W output and can be had for under $25 USD if you know where to look. It’s paired with a Raspberry Pi Zero 2W, which is the brains of the operation. The Pi is hooked up to the All-In-One-Cable which is basically a soundcard-like interface that plugs into USB and hooks up to the mic and speaker outputs of the Baofeng handheld. The final pieces of the puzzle are a USB PD battery pack and a small OLED screen to display status information.

What does that kit get you? The capability to transmit on all sorts of digital modes with the aid of the DigiPi software package. You can send emails, jump on APRS, or even chat on the web. You can configure all of this through a web interface running on the Raspberry Pi.

We’ve looked at some interesting digital ham projects before, too. Video after the break.

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When USB Charger Marketing Claims Are Technically True

October 3, 2025 by 19 Comments
The 600W is not the output rating, despite all appearances. (Credit: Denki Otaku, YouTube)
The 600W is not the output rating, despite all appearances. (Credit: Denki Otaku, YouTube)

We have seen many scam USB chargers appear over the years, with a number of them being enthusiastically ripped apart and analyzed by fairly tame electrical engineers. Often these are obvious scams with clear fire risks, massively overstated claims and/or electrocution hazards. This is where the “600W” multi-port USB charger from AliExpress that [Denki Otaku] looked at is so fascinating, as despite only outputting 170 Watt before cutting out, it’s technically not lying in its marketing and generally well-engineered.

The trick being that the “600W” is effectively just the model name, even if you could mistake it for the summed up output power as listed on the ports. The claimed GaN components are also there, with all three claimed parts counted and present in the main power conversion stages, along with the expected efficiency gains.

While testing USB-PD voltages and current on the USB-C ports, the supported USB-PD EPR wattage and voltages significantly reduce when you start using ports, indicating that they’re clearly being shared, but this is all listed on the product page.

The main PCB of the unit generates the 28 VDC that’s also the maximum voltage that the USB-C ports can output, with lower voltages generated as needed. On the PCB with the USB ports we find the step-down converters for this, as well as the USB-PD and other USB charging control chips. With only a limited number of these to go around, the controller will change the current per port dynamically as the load increases, as you would expect.

Considering that this particular charger can be bought for around $30, is up-front about the limitations and uses GaN, while a genuine 300 Watt charger from a brand like Anker goes for $140+, it leads one to question the expectations of the buyer more than anything. While not an outright scam like those outrageous $20 ‘2 TB’ SSDs, it does seem to prey on people who have little technical understanding of what crazy amounts of cash you’d have to spend for a genuine 600 Watt GaN multi-port USB charger, never mind how big such a unit would be.

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DIY astrophotography camera

Cold Sensor, Hot Results: Upgrading A DSLR For Astrophotography

October 3, 2025 by 13 Comments

When taking pictures of the night sky, any noise picked up by the sensor can obscure the desired result. One major cause of noise in CMOS sensors is heat—even small amounts can degrade the final image. To combat this, [Francisco C] of Deep SkyLab retrofitted an old Canon T1i DSLR with an external cooler to reduce thermal noise, which introduces random pixel variations that can hide faint stars.

While dedicated astrophotography cameras exist—and [Francisco C] even owns one—he wanted to see if he could improve an old DSLR by actively cooling its image sensor. He began with minor surgery, removing the rear panel and screen to expose the back of the sensor. Using a sub-$20 Peltier cooler (also called a TEC, or Thermoelectric Cooler), he placed its cold side against the sensor, creating a path to draw heat away.

Reassembling the camera required some compromises, such as leaving off the LCD screen due to space constraints. To prevent light leaks, [Francisco C] covered the exposed PCBs and viewfinder with tape. He then tested the setup, taking photos with the TEC disabled and enabled. Without cooling, the sensor started at 67°F but quickly rose to 88°F in sequential shots. With the TEC enabled, the sensor remained steady at 67°F across all shots, yielding a 2.8x improvement in the signal-to-noise ratio. Thanks to [Francisco C] for sharing this project! Check out his project page for more details, and explore our other astrophotography hacks for inspiration.

 

 

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Build A 3D Printed Tide Clock So You Know When The Sea Is Coming To Get You

October 3, 2025 by 8 Comments

The tides! Such a unique thing, because on Earth, we don’t just have oceans full of liquid water—we also have a big ol’ moon called Moon to pull them around. You might like to keep track of the tides; if so, this tide clock from [rabbitcreek] could come in handy.

The motions of the tides are moderately complex; it was in the late 19th century that Sir William Thomson figured out a reasonable method to predict the tides mathematically and with a mechanical contrivance of his own design. These days, though, you don’t need pulleys and ropes to build a tide clock; you can just use electronics for display and the NOAA API to get the information you need.

[rabbitcreek’s] build is based around the Xiao ESP32 S3, which is charged with using its Wi-Fi connection to query NOAA up-to-date tide height data. It then uses this information to drive the position of a servo, installed inside a 3D-printed housing. The servo rotates a little red Moon indicator around a central Earth, with our home planet surrounded by a stretched blue marker indicating the swelling of the tides as influenced by the Moon’s gravity.

If you’re a surfer or beach driver that’s always wanting to know the tidal state at a glance, this clock is for you. We’ve featured other tide clocks before, but never any projects that can actually influence the tides themselves. If you’ve figured out how to mess with gravity on a planetary scale, consider applying for a Nobel Prize—but do notify the tipsline before you do.

A man is shown behind a table, on which a glass apparatus like a distillation apparatus is set, with outlets leading into a large container in the center of the table, and from there to a pump.

Pulling A High Vacuum With Boiling Mercury

October 3, 2025 by 20 Comments

If you need to create a high vacuum, there are basically two options: turbomolecular pumps and diffusion pumps. Turbomolecular pumps require rotors spinning at many thousands of rotations per minute and must be carefully balanced to avoid a violent self-disassembly, but diffusion pumps aren’t without danger either, particularly if, like [Advanced Tinkering], you use mercury as your working fluid. Between the high vacuum, boiling mercury, and the previous two being contained in fragile glassware, this is a project that takes steady nerves to attempt – and could considerably unsteady those nerves if something were to go wrong.

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