Bubble Displays Make A Neat Retro Clock

May 28, 2025 by Jenny List 6 Comments

In 2025 we are spoiled for choice when it comes to displays, with affordable LCDs, OLEDs, TFTs, and e-ink panels of all sizes only a few clicks away. But in decades past, such exotica were not on the menu for casual construction. Instead there were a range of LED seven segment displays which have now largely passed out of use.

Among them were HP’s bubble displays, assemblies of miniature LEDs on a PCB, topped with plastic bubble lenses. If you had a calculator in the 1970s it probably had one, but in the present, [Joshua Coleman] has incorporated one into a pleasingly retro digital clock.

Inside the 3D printed case is an ESP32 with a pair of 74HC595 shift registers to drive the display, and an 18650 battery with all associated charging and protection circuitry. It’s a surprisingly simple circuit, and the code is provided on the page. He makes an apology to non-Americans for his use of US date formats, but we think few readers will be unable to change it to reflect the only date format which really matters.

If you find a bubble display, hang on to it. They’re certainly something we’ve seen before here a few times.

Trashed Sound System Lives To Rock Another Day

May 22, 2025 by Bryan Cockfield 6 Comments

Plenty of consumer goods, from passenger vehicles to toys to electronics, get tossed out prematurely for all kinds of reasons. Repairable damage, market trends, planned obsolescence, and bad design can all lead to an early sunset on something that might still have some useful life in it. This was certainly the case for a sound system that [Bill] found — despite a set of good speakers, the poor design of the hardware combined with some damage was enough for the owner to toss it. But [Bill] took up the challenge to get it back in working order again.

The main problem with this unit is that of design. It relies on a remote control to turn it on and operate everything, and if that breaks or is lost, the entire unit won’t even power on. Tracing the remote back to the control board reveals a 15-pin connector, and some other audio sleuths online have a few ways of using this port to control the system without the remote.

[Bill] found a few mistakes that needed to be corrected, and was eventually able to get an ESP8266 (and eventually an ESP32) to control the unit thanks largely to the fact that it communicates using a slightly modified I2C protocol.

There were a few pieces of physical damage to correct, too. First, the AC power cable had been cut off which was simple enough to replace, but [Bill] also found that a power connector inside the unit was loose as well. With that taken care of he has a perfectly functional and remarkably inexpensive sound system ready for movies or music. There are some other options available for getting a set of speakers blasting tunes again as well, like building the amplifier for them from scratch from the get-go.

The Screamer Is Just Like The Clapper But Even More Annoying

May 16, 2025 by Lewin Day 11 Comments

Remember The Clapper? It was a home automation tool (of sorts) that let you turn appliances on and off by clapping. [Kevin O’Connor] has built something rather similar, if more terrifying. It’s called The Screamer.

The build is based around a Sonoff S31 smart switch. [Kevin] selected an off-the-shelf device because he wanted something that was safe to use with mains power out of the box. But specifically, he selected the S31 because it has an ESP8266 inside that’s easy to reprogram with the aid of ESPHome. He ended up hooking up a whole extra ESP32 with an INMP441 microphone over I2S to do the scream detection. This was achieved with a simple algorithm that looked for high amplitude noises with lots of energy in the 1000 – 4000 Hz frequency range. When a scream is detected, it flips a GPIO pin which is detected by the S31, which then toggles the state of the smart switch in turn. Job done.

It’s a simple project that does exactly what it says on the tin. It’s The Screamer! If you’d like to learn more about the original Clapper that inspired this build, we’ve looked at that before, too. Meanwhile, if you’re cooking up your own excuses to scream at the lights and walls in your home, please only notify the tipsline if it has something vaguely to do with electronics or hackery.

Smart Terrarium Run By ESP32

May 15, 2025 by Lewin Day 8 Comments

A terrarium is a little piece of the living world captured in a small enclosure you can pop on your desk or coffee table at home. If you want to keep it as alive as possible, though, you might like to implement some controls. That’s precisely what [yotitote] did with their smart terrarium build.

At the heart of the build is an ESP32 microcontroller. It’s armed with temperature and humidity sensors to detect the state of the atmosphere within the terrarium itself. However, it’s not just a mere monitor. It’s able to influence conditions by activating an ultrasonic fogger to increase humidity (which slightly impacts temperature in turn). There are also LED strips, which the ESP32 controls in order to try and aid the growth of plants within, and a small OLED screen to keep an eye on the vital signs.

It’s a simple project, but one that serves as a basic starting point that could be readily expanded as needed. It wouldn’t take much to adapt this further, such as by adding heating elements for precise temperature control, or more advanced lighting systems. These could be particularly useful if you intend your terrarium to support, perhaps, reptiles, in addition to tropical plant life.

Indeed, we’ve seen similar work before, using a Raspberry Pi to create a positive environment to keep geckos alive! Meanwhile, if you’re cooking up your own advanced terrarium at home, don’t hesitate to let us know.

A Web Based Controller For Your Garage Door

May 13, 2025 by Lewin Day 17 Comments

Garage doors! You could get out of your vehicle and open and close them yourself, but that kinda sucks. It’s much preferable to have them raise and lower courtesy some mechanical contrivance, and even better if that is controlled via the web. [Juan Schiavoni] shows us how to achieve the latter with their latest project.

The web-based controller is based around a Xiao ESP32 microcontroller board, chosen for its baked-in WiFi connectivity. It’s set up to host its own web interface which you can login to with a password via a browser. If you have the correct authorization, you can then hit a button to open or close the garage door.

To interface the ESP32 with the garage door itself, [Juan] went the easy route. To trigger opening or closing the door, the ESP32 merely flicks an IO pin to toggle a transistor, which is hooked up to the button of the original garage door opener. Meanwhile, the ESP32 is also hooked up with a magnetic switch which is activated by a magnet on the garage door itself. This serves as a crude indicator as to the current status of the door—whether currently open or closed. This is crucial to ensure the indicated door status shown in the web app remains synced with the status of the door in reality.

It’s a simple project, and reminds us that we needn’t always do things the hard way. [Juan] could have figured out how to hook the ESP32 up with some radio chips to emulate the original garage door opener, but why bother? hooking it up to the original remote was far easier and more reliable anyway. We’ve seen a good few garage door hacks over the years; if you’ve got your own unique take on this classic, don’t hesitate to notify the tipsline!

[Thanks to Stillman for the tip!]

Web Dashboard And OTA Updates For The ESP32

May 10, 2025 by John Elliot V 10 Comments

Today we are happy to present a web-based GUI for making a web-based GUI! If you’re a programmer then web front-end development might not be your bag. But a web-based graphical user interface (GUI) for administration and reporting for your microcontroller device can look very professional and be super useful. The Mongoose Wizard can help you develop a device dashboard for your ESP32-based project.

In this article (and associated video) the Mongoose developers run you through how to get started with their technology. They help you get your development environment set up, create your dashboard layout, add a dashboard page, add a device settings page, add an over-the-air (OTA) firmware update page, build and test the firmware, and attach the user-interface controls to the hardware. The generated firmware includes an embedded web server for serving your dashboard and delivering its REST interface, pretty handy.

You will find no end of ESP32-based projects here at Hackaday which you could potentially integrate with Mongoose. We think the OTA support is an excellent feature to have, but of course there are other ways of supporting that functionality.

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A New, Smarter Universal Remote

May 6, 2025 by Matthew Carlson 21 Comments

The remote for [Dillan Stock]’s TV broke, so he built a remote. Not just as a replacement but as something new. For some of us, there was a glorious time in the early 2000s when a smart remote was needed and there were options you could buy off the shelf. Just one handy button next to the screen had a macro programmed that would turn on the receiver, DVD player, and TV, and then configure it with the right inputs. However, the march of technological convenience has continued and nowadays soundbars turn on just in time and the TV auto switches the input. Many devices are (for better or worse) connected to WiFi, allowing all sorts of automation.

[Dillan] was lucky enough that his devices were connected to his home assistant setup. So this remote is an ESP32 running ESPHome. These automations could be triggered by your phone or via voice assistant. What is more interesting is watching [Dillan] go through the design process. Deciding what buttons there should be, where they should be placed, and how the case would snap together takes real effort. The design uses all through-hole components except for the ESP32 which is a module.

This isn’t the first thing [Dillan] has made with an ESP32, as he previously revamped a non-standard smart lamp with the versatile dev board. The 3d printable files for the remote are free available. Video after the break.

Continue reading “A New, Smarter Universal Remote” →