One part wants 3.3V logic. Another wants 5V. What do you do? Over on the [Playduino] YouTube channel, there’s a recent video running us through a not-so-recent concern: various approaches to level-shifting.

In the video, the specific voltage domains of 3.3 volts and 5 volts are given, but you can apply the same principles to other voltage domains, such as 1.8 volts, 2.5 volts, or nearly any two levels. Various approaches are discussed depending on whether you are interfacing 5 V to 3.3 V or 3.3 V to 5 V.

The first way to convert 5 V into 3.3 V is to use a voltage divider, made from two resistors. This is a balancing act: if the resistors are too small, the circuit wastes power; if they are too large, they inhibit fast signals.

The second approach to converting 5 V into 3.3 V is to use a bare resistor of at least 10K. This is a controversial approach, but it may work in your situation. The trick is to rely on the voltage drop across the series resistor to either drop enough voltage or limit the current flowing through input protection diodes, which will clamp the voltage but also burn out with too much current flow.

The third approach to converting 5 V into 3.3 V is to use chips from the 74AHC series or 74LVC series, such as inverting or non-inverting buffers. These chips can do the level shifting for you.

The easiest approach for going in the other direction is to simply connect them directly and hope you get lucky! Needless to say, this approach is fraught with peril.

The second approach for converting 3.3 V into 5 V is to make your own inverting or non-inverting buffer using, in this case, an N-channel Enhancement-mode MOSFET. Use one MOSFET for an inverting buffer and two MOSFETs for a non-inverting buffer. Just make sure you pick N-MOSFETs with 3.3 V or 5 V gate drive voltage V_GS. Alternatively, you can use a buffer from the 74HCT series.

The video provides a myriad of approaches to level shifting, but you still have to decide. Do you have a favorite approach that wasn’t listed? Have you had good or bad luck with any of the approaches? Let us know in the comments! For more info on level shifting, including things to watch out for, check out When Your Level Shifter Is Too Smart To Function.

Over on YouTube [Drake] from the [styropyro] channel investigates what happens when you take an enormous tungsten incandescent light bulb and pump 30,000 watts through it.

The answer: it burns bright enough to light up the forest at night, and hot enough to cook food and melt metal. And why on Earth would anybody do such a thing? Well [Drake] said it was because he wanted to outdo [Photonicinduction] who had already put 20,000 watts through a light bulb. Nothing like a little friendly competition to drive… progress?

[Drake] says he has purchased the most powerful incandescent light bulb ever made for commercial production. Rated for 24,000 watts (and operated at 30,000 watts) the enormous filament is made from tungsten. The starting current drawn by a light bulb is higher than the operating current, because the resistance of the filament increases with temperature, so it’s prudent to warm the device slowly. To this end [Drake] builds some custom wiring and dials to power the thing. Once that’s done, it’s off to the forest to play!

If you’re interested in over-the-top lighting shenanigans, you might enjoy reading about The World’s Longest Range LED Flashlight.

Here’s a fun rabbit hole to run down if you don’t already have the RP2040/RP2350 PIO feather in your cap: how to serve data without CPU intervention using PIO and DMA on the RP2350.

If you don’t know much about the RP2040 or RP2350 here’s the basic run down: the original Raspberry Pi Pico was released in 2021 with the RP2040 at its heart, with the RP2350 making its debut in 2024 with the Pico 2. Both microcontrollers include a feature known as Programmed I/O (PIO), which lets you configure tiny state machines and other facilities (shift registers, scratch registers, FIFO buffers, etc) to process simple I/O logic, freeing up the CPU to do other tasks.

The bottom line is that you can write very simple programs to do very fast and efficient I/O and these programs can run separately to the other code running on your micro. In the video below, [piers] explains how it works and how he’s used it in his One ROM project.

This is the latest installment from [piers rocks] whose One ROM project we’ve been tracking since July this year when we first heard about it. Since then we’ve been watching this project grow up and we were there when it was only implemented on the STM32F4, when it was renamed to One ROM, and when it got its USB stack. Along the way [piers rocks] was on FLOSS Weekly Episode 850: One ROM To Rule Them All too.

Have you seen PIO being put to good use in other projects? Let us know in the comments, or on the tips line!

In a recent video, [Jason Jacques] demos the Busch Electronic Digital-Technik 2075 which was released in West Germany in the 1970s.

The Digital-Technik 2075 comes with a few components including a battery holder and 9 V battery, a push button, two 1 K resistors, a red LED, a 100 nF ceramic capacitor, a 100 µF electrolytic capacitor, a quad NAND gate IC, and a counter module which includes an IC and a 7-segment display. The kit also comes with wires, plugs, a breadboard, and a tool for extracting modules.

The Digital-Technik 2075 doesn’t use the spring terminals we see in other project labs of the time, such as the Science Fair kits from Radio Shack, and it doesn’t use modular Denshi blocks, such as we saw from the Gakken EX-150, but rather uses wire in conjunction with yellow plastic plugs. This seems to work well enough.

In the video, after showing us how to do switch debouncing, [Jason] runs us through making a counter with the digital components and then getting the counter to reset after it counts to five. This is done using NAND gates. Before he gets stuck into doing a project he takes a close look at the manual (which is in German) including some of the advertisements for other project labs from Busch which were available at the time. As he doesn’t speak German [Jason] prints out an English translation of the manual before working through it.

We’ve heard from [Jason] at Hackaday in recent history when we saw his Microtronic Phoenix Computer System which referenced the 2090 Microtronic Computer System which was also made by Busch.

The Bomem DA3 is a type of Fourier transform spectrometer used for measuring various spectral data and [Usagi Electric] has one. On his quest to understand it he runs down a number of rabbit holes, including learning about various barcode formats, doing a teardown of the Telxon LS-201 barcode scanner, and exploring how lasers work. That’s right: lasers!

His reason for looking at the Telxon LS-201 barcode scanner is that it has the same type of helium-neon laser as his Bomem DA3 uses. Since he’s learning about barcode scanners he thinks it’s prudent to learn about barcode formats too, and he has a discussion with our very own Adam Fabio about such things, including the UPC-A standard barcodes.

It’s fun seeing the mainboard of the Telxon LS-201 sporting the familiar 555 timer, LM393 comparator, and three op-amps: 5532, LF347, and TL062; no discrete logic in sight! If you’re interested in barcode tech you might like to read Barcodes Enter The Matrix In 2027 and Old Barcode Scanner Motherboards Live Again. The particular Hackaday article mentioned in the video is this one: The Eloquence Of The Barcode.

Also, in the interest of public health and safety, make sure you’re wearing laser protection glasses if you’re working with laser technology. Even low power lasers can do damage to your eyes. Laser emissions can be invisible to the human eye and you don’t have nerves that tell you when your eyeballs are being roasted, so take care out there!