7-segment display

44 Articles

Mechanical 7-Segment Display Looks Clean

May 21, 2024 by 3 Comments

[Jens] wanted a subscriber counter for his YouTube channel. He could have gone with a simple OLED, LCD, or LED display, but he wanted something more tactile and interesting. So he built a mechanical 7-segment display instead!

Currently, [Jens]’s channel is in the four-digit subscriber range, so he planned to build a four-digit display. He started by searching for existing projects in this space, and came across the designs of [shiura] on Thingiverse. [shiura] had a 3D printed cam-driven 7-segment digit that runs on a single servo motor. Once armed with four of the digits, he hooked them up to a Pi Pico W to drive them all with four servo outputs. The Pico W is responsible for querying the channel subscriber count online, and updating the display in turn.

It’s a neat build, and [Jens] learned some things along the way—like how Super Lube seemed to ruin filament for him. Ultimately, the build came good, and it looks great. We’ve seen some other mechanical 7-segment builds before, too!

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Saving A Clock Radio With An LM8562

March 28, 2024 by 12 Comments

Smart phones have taken the place of a lot of different devices especially as they get more and more powerful. GPS, music and video player, email, and of course a phone are all functions tied up in these general-purpose devices. Another casualty of the smart phone revolution is the humble bedside alarm clock as its radio, alarm, and timekeeping functionalities are also provided by modern devices. [zst123] has a sentimental attachment to the one he used in the 00s, though, and set about restoring it to its former glory.

Most of the issue with the clock involved drift with the timekeeping circuitry. Since it wasn’t accurately keeping the time anymore, losing around 10 minutes a day, the goal to save it was to use NTP to get the current time and a microcontroller to make the correction automatically. Rather than replace everything in the clock except the display, [zst123] is using the existing circuit board and adding an ESP8266 to grab the time from the Internet. A custom driver board reads the current time displayed on the clock directly from the display itself and then the ESP8266 can adjust it by using the existing buttons through a relay wired in parallel.

Using the existing circuitry was certainly a challenge especially since the display was multiplexed, but the LM8562 that came with these clock radios is a common and well-documented chip for driving displays like this, giving [zst123] a leg up over something unlabeled or proprietary. Using NTP is certainly a reliable and straightforward way of getting the current time too but there are a few other options for projects like these like using GPS or even a radio signal.

Kitchen timer project in a angled green 3d printed case with a 7 segment display and knob.

Printing A Brutalist Kitchen Timer

April 2, 2023 by 23 Comments

A kitchen timer is one of those projects that’s well defined enough to have a clear goal, but allows plenty of room for experimentation with functionality and aesthetics. [Hggh]’s exploration of the idea is a clean, Brutalist kitchen timer.

The case for [Hggh]’s kitchen timer is 3D printed with openings for a TM1637 four digit, seven segment display and for a KY-040 rotary encoder with knob attached. The internals are driven by an ATmega328P powered from a 18650 cell with a DW01-P battery protection chip and a TP4056 chip for charging. On the back of the case is a power switch and USB-C connector for power. It looks like the 3D printed case was sanded down to give it a smooth matte surface finish.

All the project files, including the STLs, OpenSCAD code, and KiCAD design, are available on GitHub. This Brutalist kitchen timer project is a nice addition to some of the kitchen timers we’ve featured in the past, including a minimalist LED matrix timer and a Nixie timer with keypad.

Triple Zone Clock Tells Time In Style

January 6, 2023 by 9 Comments

Although the cutoff for saying ‘Happy New Year’ is somewhere around today, there’s still plenty of time to reminisce about 2022 and all that we accomplished. Hackaday alum [Jeremy Cook] spent much of last year designing and building a triple-zone PCB clock, dubbed the 742 clock. It is called so because of all the 7-segments, and then 42 from the height in millimeters of each PCB. Also because it’s 24 backwards, and if we may be so bold, because 42.

If this looks familiar, it’s because we covered the single-panel version a few months ago. Much like that one, the triple time zone clock is controlled by a single Wemos D1 mini, and the other two panels are chained to the primary board. This version has a frame made of 20/20 extrusion with nice 3D printed caps on the ends to finish off the look.

As with the single-panel clock, this one uses bared-FR4 PCBs to diffuse the LEDs, and the effect looks really nice. We particularly like the capacitive corners that control the clock and the colors, which change throughout the day when left to their own devices. Be sure to check out the build video after the break.

Are you really into LEDs? Consider building a Berlin clock.

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Simple Stopwatch with two buttons, an eight digit 7-segment display and ICSP programming cable going into the board

Add An OSHW Certified Stopwatch To Your Toolkit

September 23, 2022 by 5 Comments

[MakingDevices] has created a simple stopwatch that makes for a nice introduction to surface mount electronic design and assembly. The project is open source hardware (OSHW) certified, with Gerbers, KiCAD files, and software all available.

Conceptually the stopwatch is straight forward, with a row of two four digit seven-segment displays being driven by a PIC18LF14k50 microcontroller through multiple NPN transistors. The PIC doesn’t quite have enough data lines to drive the two displays at once so an inverter is used to toggle between the two seven-segment blocks.

The circuit is continuously powered from a CR2032 coin cell battery. For normal usage with display, [MakingDevices] estimates 30+ hours of operation and 140+ hours without display, but still counting time. When idle, the “Extreme Low-Power (XLP)” capabilities of the PIC put the operating window estimates well beyond the self discharge of the coin cell battery. There’s an in circuit serial programming (ICSP) footprint that accepts a pogo pin TC2030-MCP-NL adapter for flashing the PIC.

Don’t let the simplicity fool you, this is a well documented project with detailed posts about the design, simulation and battery consumption. Various videos and glamour shots give a whole picture of the process, from design, assembly, testing to final validation.

It’d be wonderful to see the project extended or hacked on further, perhaps with a cute enclosure or case.

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You Can Build A Giant 7-Segment Display Of Your Very Own

July 27, 2022 by 7 Comments

Sometimes you need to display a number nice and large, making it easily readable at a good distance. [Lewis] has just the thing for that: a big expandable 7-segment display.

The build is modular, allowing it to be extended from 2 to 10 digits and beyond. The digits themselves are made of 3D-printed parts assembled onto acrylic. These can then be ganged up in a wooden frame for displaying larger numbers with more digits. Individual elements are lit by addressable LEDs, and the project can be built using an Arduino Nano or an ESP8266 for control. The latter opens up possibilities for controlling the screen over WiFi, which could prove useful.

[Lewis] has built his own version for a local swim club, where it will be used as a laptimer. Other applications could be as a scoreboard in various sports, or to confuse your neighbours by displaying random numbers in your front yard.

We’ve seen a similar build from [Ivan Miranda] that served well as a workshop clock, too. Video after the break.

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RGB 7-Segment Display Module Glows In All The Colours

June 19, 2022 by 4 Comments

While 7-segment displays are all well and good, they’re considered a bit old hat these days. This project from [Matt Deeds] brings them screaming into the future, though, sporting every color under the rainbow.

[Matt’s] build consists of a PCB filled with SK6812 side-mount LEDs, laid out in a typical 7-segment pattern. Each PCB features two 7-segment digits. The SK6812 LEDs can be driven in the same way as the famous WS2812B addressable LEDs, though they have the benefit of being more stable in color and brightness over a range of supply voltages.

With the LEDs installed, and a second PCB used solely as a diffuser by leaving out sections of solder mask, it’s a compact 7-segment solution at just 2.7 mm thick. The bonus is that each segment can be set to a different color thanks to the nature of the addressable RGB LEDs. Going too ham in this regard will make the displays difficult to read, but it can be used to easily display green, red, or yellow numbers, for example, to create a visual guide to a numerical range.

It’s a great build, and we love to see 7-segment displays re-imagined in different ways – even mechanically! It also takes fewer pins to drive compared to the old way of doing things in the non-addressable LED era. If you’ve got your own neat 7-segment projects under development, please do let us know!