Peripherals Hacks

1488 Articles

This Device Is A Real Page Turner

September 22, 2025 by 6 Comments

You can read e-books on just about anything—your tablet, your smartphone, or even your PC. However, the interface can be lacking somewhat compared to a traditional book—on a computer, you have to use the keyboard or mouse to flip the pages. Alternatively, you could do what [NovemberKou] did, and build a dedicated page-turning device.

The device was specifically designed for use with the Kindle for Mac or Kindle for PC reader apps, allowing the user to peruse their chosen literature without using the keyboard to change pages. It consists of a thumb wheel, rotary encoder, and an Arduino Pro Micro mounted in a 3D printed shell. The Pro Micro is set up to emulate a USB keyboard, sending “Page Up” or “Page Down” key presses as you turn the thum bwheel in either direction.

Is it a frivolous device with a very specific purpose? Yes, and that’s why we love it. There’s something charming about building a bespoke interface device just to increase your reading pleasure, and we wholeheartedly support it.

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Restoring A Vintage Computer And Its Plotter

September 22, 2025 by 19 Comments

Repairing vintage computers is bread-and-butter for many of us around here. The machines themselves tend to be fairly fixable, assuming spare parts are available and there hasn’t been too much physical damage. Peripherals can be another matter, though. Since they interface with the real world they can have more esoteric problems that aren’t always solvable. [joekutz] was handed just such a device in the form of a CE-150 docking station for a Sharp PC1500 Pocket Computer, which has a plotter built in. Here’s his “tip” for getting plotters like these working again.

The first step here is to disassemble the original, dried out pens to scavenge a few of the parts. The outer case needs to be kept so that it can be put back into the plotter, and a small O-ring is saved as well. To replace the dried-out tips [joekutz] discards the original tips and replaces them with tips from a common ink pen, using shrink wrap tubing to help fit the pen’s tip into the original plotter cylinder. He also takes the ink from the pen to fill the plotter’s cartridge, completing the surgery on the multi-colored plotter and bringing it back to life.

Of course this build goes well beyond the plotter, including bringing the PC1500 back to life as well. There are a few other videos about this project covering that original restoration as well as demonstrating some of the quirks of how this computer is meant to be programmed. But we mostly focused on the plotter here since that is a little bit out of the ordinary, and we’re also sure that refilling ink cartridges of any sort gets under the skin of everyone at HP.

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A Serial Mouse For A Homebrew 8-bit Computer

September 21, 2025 by 2 Comments

[Too Many Wires] has a custom computer he’s building. He wanted a mouse, but USB is a bit of a stretch for the fledgling computer. We might have opted for PS/2, but he went for something even older: a serial mouse connected with a DE-9 (colloquially, a DB-9). Check it out in his recent video update on the project below.

Don’t remember serial mice? They were very common many years ago, and apparently, you can still buy new ones, which makes you wonder what people are doing with them. If you are an old hand at serial, you’ll immediately know why he couldn’t get it to work at first. If you haven’t worked with RS-232 gear before, you’ll learn a lot.

The protocol is simple enough, and you can read the code or find plenty of old documents. He’s using a UART chip, which offloads the CPU. However, the PS/2 mice are very easy to work with directly, and you could skip the +/- 12V RS-232 and other issues.

Either way, however, using an RS-232 or PS/2 mouse in a project is relatively straightforward. You might not think you need a mouse, but don’t forget, they are really accurate two-axis sensors. An optical mouse on a motion table, for example, could be worth something.

The computer is based on [Ben Eater]’s design, if you want more details on that. Can’t decide between RS-232 and PS/2? You don’t have to.

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The Android Linux Commander

September 9, 2025 by 7 Comments

Last time, I described how to write a simple Android app and get it talking to your code on Linux. So, of course, we need an example. Since I’ve been on something of a macropad kick lately, I decided to write a toolkit for building your own macropad using App Inventor and any sort of Linux tools you like.

I mentioned there is a server. I wrote some very basic code to exchange data with the Android device on the Linux side. The protocol is simple:

  • All messages to the ordinary Linux start with >
  • All messages to the Android device start with <
  • All messages end with a carriage return

Security

You can build the server so that it can execute arbitrary commands. Since some people will doubtlessly be upset about that, the server can also have a restrictive set of numbered commands. You can also allow those commands to take arguments or disallow them, but you have to rebuild the server with your options set.

There is a handshake at the start of communications where Android sends “>.” and the server responds “<.” to allow synchronization and any resetting to occur. Sending “>#x” runs a numbered command (where x is an integer) which could have arguments like “>#20~/todo.txt” for example, or, with no arguments, “>#20” if you just want to run the command.

If the server allows it, you can also just send an entire command line using “>>” as in: “>>vi ~/todo.txt” to start a vi session.

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Open source mute button

Silent No More: Open-Source Fix For Mic Mishaps

August 30, 2025 by 12 Comments

“Sorry, my mic was muted…” With the rise of video calls, we’ve all found ourselves rushing to mute or unmute our mics in the midst of a call. This open-source Mute Button, sent in by [blackdevice], aims to take out the uncertainty and make toggling your mic easy.

It’s centered around a small PIC32MM microcontroller that handles the USB communications, controls the three built-in RGB LEDs, and reads the inputs from the encoder mounted to the center of this small device. The button knob combo is small enough to easily move around your desk, yet large enough to toggle without fuss when it’s your turn to talk.

To utilize all the functions of the button, you’ll need to install the Python-based driver on your machine. Doing so will let you not only toggle your microphone and volume, but it will also allow the button to light up to get your attention should you be trying to talk with the mic muted.

Although small, it’s also quite rugged, knowing it will spend its life being treated much like a game of Whac-A-Mole—slapped whenever needed. The case is designed to be 3D printed by any FDM printer, with the top knob section printed in translucent material to make the notification light clearly visible.

All of the design files, firmware, and parts list are available over on [blackdevices]’s GitHub page, and they are open-source, allowing you to tweak the design to fit your unique needs. Thank you for sending in this well-documented project, [blackdevices]; we look forward to seeing future work. If you like this type of thing, be sure to check out some of our other cool featured desk gadgets.

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Debugging The Instant Macropad

August 25, 2025 by No comments

Last time, I showed you how to throw together a few modules and make a working macropad that could act like a keyboard or a mouse. My prototype was very simple, so there wasn’t much to debug. But what happens if you want to do something more complex? In this installment, I’ll show you how to add the obligatory blinking LED and, just to make it interesting, a custom macro key.

There is a way to print data from the keyboard, through the USB port, and into a program that knows how to listen for it. There are a few choices, but the qmk software can do it if you run it with the console argument.

The Plan

In theory, it is fairly easy to just add the console feature to the keyboard.json file:

{
...
    "features": {
        "mousekey": true,
        "extrakey": true,
        "nkro": false,
        "bootmagic": false,
        "console": true
    },
...

That allows the console to attach, but now you have to print.

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Pinout of 74HC595

Using The 74HC595 Shift Register To Drive 7-Segment Displays

August 21, 2025 by 19 Comments

In a recent video our hacker [Electronic Wizard] introduces the 74HC595 shift register and explains how to use it to drive 7-segment displays.

[Electronic Wizard] explains that understanding how to apply the 74HC595 can increase the quality of your projects and also help keep the demands on the number of pins from your microcontroller to manageable levels. If you’re interested in the gory details you can find a PDF datasheet for the 74HC595 such as this one from Texas Instruments.

[Electronic Wizard] explains further that a shift register is like a small one byte memory where its data is directly available on its eight output pins, no input address required. When you pulse the clock pin (CLK) each bit in the eight bit memory shifts right one bit, making room for a new bit on the left. The bits that fall off the right hand side can daisy chain into another 74HC595 going out on pin 9 and coming in on pin 14.

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