Drawing Tablet Controls Laser In Real-Time

April 1, 2026 by Donald Papp 1 Comment

Some projects need no complicated use case to justify their development, and so it was with [Janne]’s BeamInk, which mashes a Wacom pen tablet with an xTool F1 laser engraver with the help of a little digital glue. For what purpose? So one can use a digital pen to draw with a laser in real time, of course!

Pen events from the drawing tablet get translated into a stream of G-code that controls laser state and power.

Here’s how it works: a Python script grabs events from a USB drawing tablet via evdev (the Linux kernel’s event device, which allows user programs to read raw device events), scales the tablet size to the laser’s working area, and turns pen events into a stream of laser power and movement G-code. The result? Draw on tablet, receive laser engraving.

It’s a playful project, but it also exists as a highly modular concept that can be adapted to different uses. If you’re looking at this and sensing a visit from the Good Ideas Fairy, check out the GitHub repository for more technical details plus tips for adapting it to other hardware.

We’re reminded of past projects like a laser cutter with Etch-a-Sketch controls as well as an attempt to turn pen marks into laser cuts, but something about using a drawing tablet for real-time laser control makes this stand on its own.

A Novel 555 Circuit In 2026

April 1, 2026 by Jenny List 6 Comments

The humble NE555 has been around for over five decades now, and while during that time we’ve seen a succession of better and faster versions of the original, the circuits which surround it are pretty well known. There can’t be anything new in the world of 555s, can there? [Stephen Woodward] claims he’s made a novel 555 circuit, with his 1 MHz linear voltage to frequency converter. Since he’s been in love with the 555 since 1974, we’re inclined to trust him on this part.

It’s visibly the 555 astable oscillator we’re all familiar with, given the addition of a current source in place of the normal charging resistor. This makes for a much more linear sawtooth waveform, but it still doesn’t fix the linearity of the voltage to frequency curve. The novel bit comes in adding an extra resistor between the threshold and discharge pins, with a value calculated for a time constant with the capacitor to match the 555’s own switching delay. This provides the necessary compensation, and gives the circuit its linearity.

This is so brilliantly simple that it’s almost a shock that it’s new, but it’s also a great example of the old-school electronic engineer’s art. We can’t think of an immediate need for a 555 voltage to frequency converter on the Hackaday bench at the moment, but you can bet we’ll come back to this one if we do.

We had someone pushing a newer 555 variant to its limit, when we ran our component abuse challenge.