keypad

57 Articles

A Custom Zigbee Touch Keypad

June 26, 2026 by No comments

[Dominic Buchstaller] wanted a neat, tidy entryway keypad that actually looked good. Prime goals were something slim, wireless, and with no visible screws. Dependency on the cloud was also a no-go. With few ready-to-go options available on the market, he set about whipping up his own.

The heart of the build is an ESP32-C6 microcontroller devboard. This device has the benefit of including Zigbee communication functionality baked right into the chip. It’s hooked up to an MPR121 capacitive touch controller, which allows different segments of the touchpad PCB to act as capacitive buttons for numerical entry. The number labels are directly printed on the PCB solder mask, so there’s no overlay or other label required on top. Power is courtesy of a 1300 mAh lithium-polymer cell which gives a useful lifespan of six months between recharges. A simple 3D-printed case holds everything together and completes the clean and simple look. [Dominic] notes that it’s possible to also use the device via Matter or Thread without a lot of changes, as the ESP32-C6 can easily handle those protocols, too.

If you’re looking for a cheap, handsome keypad for your Home Assistant setup or similar, you might find this useful. We’ve explored DIY keypad entry systems before, too. If you’ve come up with some other creative way to get into your house, car, or bank vault, be sure to notify us via the tipsline.

A T9 Keyboard For Your Smartphone

June 24, 2026 by 12 Comments

These days, most of us are fortunate enough to use smartphones with decent touchscreen keyboard capabilities. However, once upon a time, if you wanted to type something on a phone, you had to tap it out on the number keys instead. [Jarrett] is bringing that back with a custom T9 keyboard for modern phones. 

The build is designed around the keypad of the Nokia E52, a Symbian smartphone released in 2009—two years after Apple changed the game with the first iPhone. The phone keypad itself is laid over a custom PCB with Alps SKRK tactile switches corresponding to each individual key. Each is wired with a diode and the switches are scanned as a row/column array as is typical for keyboards. Reading the matrix is an ESP32-C6 microcontroller, which counts the keypresses and spits out the right letters over its Bluetooth connection to an attached smartphone or other device. Power is via a small lithium-ion battery, looked after by a TP4200 charger chip.

Overall, the keyboard works as you’d expect, allowing T9-style input to any compatible device that works with Bluetooth keyboards. [Jarrett] does have one regret, with the 0.98 N actuation force switches used leaving he keypad feeling a little mushy. The firmer 1.57 N switches were suspected to give a more satisfying response under thumb, which was a nice upgrade in the second revision build.

We’ve seen other builds in this vein before, too, albeit with bigger keys. If you’re coming up with your own esoteric input methods, don’t hesitate to notify the tipsline.

Building A Hackerspace Entry System

March 3, 2026 by 26 Comments

A hackerspace is a place that generally needs to be accessed by a wide group of people, often at weird and unusual hours. Handing around keys and making sure everything is properly locked up can be messy, too. To make it easy for hackers to get in to [Peter]’s local hackerspace, a simple electronic system was whipped up to grant access.

The combined use of QR code & PIN adds a layer of security.

The basic components of the system are a keypad, a QR code and barcode scanner, a stepper motor, an Arduino Nano, and a Raspberry Pi. The keypad is read by an Arduino Nano, which is also responsible for talking to a stepper motor driver to actuate the lock cylinder. A secondary Arduino mounted inside the building is used to control the stepper motor, which actuates the lock cylinder once authentication is complete.

The system works on the basis of two-factor authentication. Regular users authenticate to enter by presenting a QR code or barcode, and entering a matching PIN number. The system can also be set up for PIN-only entry on a temporary basis.

For example, if the hackerspace is running an event, a simple four-digit pin can allow relatively free access for the duration without compromising long-term security. Actual authentication is handled by the Raspberry Pi, which takes in the scanned barcode and/or PIN, hashes it, and checks it against a backend database which determines if the credentials are valid for entry. If so,they command the second Arduino to unlock the door.

While it’s not technically necessary for a project like this — in fact, you could argue it’s preposterously overkill — we have to take particular note of the machined aluminum enclosure for the keypad. Mere mortals could just run it off on their 3D printers, but if you’ve got access to a CNC router and a suitably chunky piece of aluminum, why not show off a bit?

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Instant Macropad: Just Add QMK

August 20, 2025 by 2 Comments

I recently picked up one of those cheap macropads (and wrote about it, of course). It is surprisingly handy and quite inexpensive. But I felt bad about buying it. Something like that should be easy to build yourself. People build keyboards all the time now, and with a small number of keys, you don’t even have to scan a matrix. Just use an I/O pin per switch.

The macropad had some wacky software on it that, luckily, people have replaced with open-source alternatives. But if I were going to roll my own, it would be smart to use something like QMK, just like a big keyboard. But that made me wonder, how much trouble it would be to set up QMK for a simple project. Spoiler: It was pretty easy.

The Hardware

Simple badge or prototype macropad? Why not both?

Since I just wanted to experiment, I was tempted to jam some switches in a breadboard along with a Raspberry Pi Pico. But then I remembered the “simple badge” project I had up on a nearby shelf. It is simplicity itself: an RP2040-Plus (you could just use a regular Pi Pico) and a small add-on board with a switch “joystick,” four buttons, and a small display. You don’t really need the Plus for this project since, unlike the badge, it doesn’t need a battery. The USB cable will power the device and carry keyboard (or even mouse) commands back to the computer.

Practical? No. But it would be easy enough to wire up any kind of switches you like. I didn’t use the display, so there would be no reason to wire one up if you were trying to make a useful copy of this project.

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Linux Fu: The Cheap Macropad Conundrum

July 30, 2025 by 10 Comments

You can get cheap no-brand macropads for almost nothing now. Some of them have just a couple of keys. Others have lots of keys, knobs, and LEDs. You can spring for a name brand, and it’ll be a good bet that it runs QMK. But the cheap ones? Get ready to download Windows-only software from suspicious Google Drive accounts. Will they work with Linux? Maybe.

Of course, if you don’t mind the keypad doing whatever it normally does, that’s fine. These are little more than HID devices with USB or Bluetooth. But what do those keys send by default? You will really want a way to remap them, especially since they may just send normal characters. So now you want to reverse engineer it. That’s a lot of work. Luckily, someone already has, at least for many of the common pads based around the CH57x chips.

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Design Constraints Bring Lockbox To Life

April 27, 2025 by 1 Comment

One of the most paradoxical aspects of creating art is the fact that constraints, whether arbitrary or real, and whether in space, time, materials, or rules, often cause creativity to flourish rather than to wither. Picasso’s blue period, Gadsby by Ernest Vincent Wright, Tetris, and even the Volkswagen Beetle are all famous examples of constraint-driven artistic brilliance. Similarly, in the world of electronics we can always reach for a microcontroller but this project from [Peter] has the constraint of only using passive components, and it is all the better for it.

The project is a lockbox, a small container that reveals a small keypad and the associated locking circuitry when opened. When the correct combination of push buttons is pressed, the box unlocks the hidden drawer. This works by setting a series of hidden switches in a certain way to program the combination. These switches are connected through various diodes to a series of relays, so that each correct press of a button activates the next relay. When the final correct button is pushed, power is applied to a solenoid which unlocks the drawer. An incorrect button push will disable a relay providing power to the rest of the relays, resetting the system back to the start.

The project uses a lot of clever tricks to do all of this without using a single microcontroller, including using capacitors that carefully provide timing to the relays to make them behave properly rather than all energizing at the same time. The woodworking is also notable as well, with the circuit components highlighted when the lid is opened (but importantly, hiding the combination switches). Using relays for logic is not a novel concept, though; they can be used for all kinds of complex tasks including replacing transistors in single-board computers.

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Metronome Flashes And Vibrates To The Beat

December 8, 2023 by 3 Comments

Annoying though they can be, if you play any kind of instrument, you will definitely benefit from using a metronome. While many of them thock or otherwise tock, the VRRVRR metronome from [Turi] works a little differently.

In addition to flashing LEDs, the VRRVRR contains a small vibrating motor. If you’re wondering about the name, it comes from the fact that it vibrates and makes a sort of vrr vrr sound. Need to be quiet? A small switch on the side shuts off the vibrations.

The 4×4 keypad really allowed [Turi] to cram in a bunch of features using both short and long press to do different things. On short press, the digits set the tempo. When not typing in a tempo, zero can be used to enter a tempo by tapping. The letters load preset tempos, and the +/- keys increase and decrease it.

Inside the basswood enclosure is a Raspberry Pi Pico, the vibration motor, and various other bits and bobs that make it go. There’s even an LED to indicate that it’s time to charge the lithium battery. If you want to build your own, head on over to GitHub, but be sure to take the brief VRRVRR tour after the break.

We don’t see too many metronomes around here, but we do have this nice teardown to offer you.

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