Trekulator: A Reproduction Of The 1977 Star Trek Themed Calculator

A recent project over on Hackaday.io from [Michael Gardi] is Trekulator – Where No Maker Has Gone Before.

This is a fun build and [Michael] has done a very good job of emulating the original device. [Michael] used the Hackaday.io logging feature to log his progress. Starting in September 2024 he modeled the case, got his original hardware working, got the 7-segment display working, added support for sound, got the keypad working and mounted it, added the TFT display and mounted it, wired up the breadboard implementation, designed and implemented the PCBs, added some finishing touches, installed improved keys, and added a power socket back in March.

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Tiny, Hackable Telepresence Robot For Under $100? Meet Goby

[Charmed Labs] are responsible for bringing numerous open-source hardware products to fruition over the years, and their latest device is an adorably small robotic camera platform called Goby, currently crowdfunding for its initial release. Goby has a few really clever design features and delivers a capable (and hackable) platform for under 100 USD.

Goby embraces its small size, delivering what its creators dub “tinypresence” — or the feeling of being there, but on a very small scale. Cardboard courses, LEGO arenas, or even tabletop gaming scenery hits different when experienced from a first-person perspective. Goby is entirely reprogrammable with nothing more than a USB cable and the Arduino IDE, while costing less than most Arduino starter kits.

Recharging happens by driving over the charger, then pivoting down so the connectors (the little blunt vampire fangs under and to each side of the camera) come into contact with the charger.

One of the physical features we really like is the tail-like articulated caster at the rear. Flexing this pivots Goby up or down (and can even flip Goby completely over), allowing one to pan and tilt the view without needing to mount the camera on a gimbal. It also comes into play for recharging; Goby simply moves over the disc-shaped charger and pivots down to make contact.

At Goby‘s heart is an ESP32-S3 and OmniVision OV2640 camera sensor streaming a live video feed (and driving controls) with WebRTC. Fitting the WebRTC stack onto an ESP32 wasn’t easy, but opens up possibilities beyond just media streaming.

Goby is set up to make launching an encrypted connection as easy as sharing a URL or scanning a QR code. The link is negotiated between bot and client with the initial help of an external server, and once a peer-to-peer connection is established, the server’s job is done and it is out of the picture. [Charmed Labs]’s code for this functionality — named BitBang — is in beta and destined for an open release as well. While BitBang is being used here to make it effortless to access Goby remotely, it’s more broadly intended to make web access for any ESP32-based device easier to implement.

As far as tiny remote camera platforms go, it might not be as small as rebuilding a Hot Wheels car into a micro RC platform, but it’s definitely more accessible and probably cheaper, to boot. Check it out at the Kickstarter (see the first link in this post) and watch it in action in the video, embedded just below the page break.

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A Cheap Yellow Display Makes A Video Walkie Talkie

The ESP32 series of microprocessors with their cheap high-power cores and built-in wireless networking have brought us a wide variety of impressive projects over the years. We’re not sure we’ve quite seen the like of [Jonathan R]’s video walkie talkie before though, a pair of units which as you might guess, deliver two-way video and audio communications.

The trick involves not one but two ESP32s: an ESP32-S3 based camera module, and a more traditional Tensilica ESP32 in a screen module. It’s an opportunity for an interesting comparison, as one device uses the Cheap Yellow Display board, and the other uses an Elecrow equivalent. The audio uses ESP-NOW, while the video uses WiFi, and since the on-board audio amplifiers aren’t great, there’s a small amp module.

The video below has a comprehensive run-down including the rationale behind the design choices, as well as a demonstration. There’s a small lag, but nothing too unacceptable for what is after all an extremely cheap device. Perhaps after all this time, the video phone has finally arrived!

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Hacking A Cheap Rechargeable Lamp With Non-Standard USB-C Connector

Recently [Dillan Stock] bought a $17 ‘mushroom’ lamp from his local Kmart that listed ‘USB-C rechargeable’ as one of its features. Unfortunately while this is technically true, there’s a pretty major asterisk. This Inaya-branded lamp comes with a USB-C cable with a rather prominent label attached to it that tells you that this lamp requires that specific cable. After trying with a regular USB-C cable, [Dillan] indeed confirmed that the lamp does not charge from a standard USB-C cable. So he did what any reasonable person would do: he bought a second unit and set about to hacking it.

The "USB C" cable that comes with the Inaya Portable Rechargeable Lamp. (Credit: The Stock Pot, YouTube)
The “USB C” cable that comes with the Inaya Portable Rechargeable Lamp. (Credit: The Stock Pot, YouTube)

[Dillan] also dug more into what’s so unusual about this cable and the connector inside the lamp. As it turns out, while GND & VCC are connected as normal, the two data lines (D+, D-) are also connected to VCC. Presumably on the lamp side this is the expected configuration, while using a regular USB-C cable causes issues. Vice versa, this cable’s configuration may actually be harmful to compliant USB-C devices, though [Dillan] did not try this.

With the second unit in hand, he started hacking in earnest. The changes include a regular USB-C port for charging, an ESP32 board with integrated battery charger for the 18650 Li-ion cell of the lamp, and an N-channel MOSFET to switch the power to the lamp’s LED. He’s made the full plans and schematics available on his website.

With all of the raw power from the ESP32 available, the two lamps got integrated into the Home Assistant network which enables features such as turning the lamps on when the alarm goes off in the morning. All of this took about $7 in parts and a few hours of work.

Although we commend [Dillan] on hacking his device instead of just returning it to the store, it’s worrying that apparently there’s now a flood of ‘USB C-powered’ devices out there that come with non-compliant cables. It brings back fond memories of hunting down proprietary charging cables, which was the issue that USB power was supposed to fix.

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An ESP32 Pomodoro Timer

The Pomdoro technique of time management has moved on a little from the tomato-shaped kitchen timer which gave it a name, as [Rukenshia] shows us with this nifty ESP32 and e-paper design. It’s relatively simple in hardware terms, being a collection of off-the-shelf modules in a 3D printed case, but the software has a custom interface for the friend it was built for.

At its heart is a NodeMCU board and a Waveshare display module, with a rotary encoder and addressable LED as further interface components. A lot of attention has been paid to the different options for the interface, and to make the front end displayed on the screen as friendly and useful as possible. Power comes via USB-C, something that should be available in most working environments here in 2025.

We’ve tried a variant on this technique for a while now with varying success, maybe because a mobile phone doesn’t make for as good a timer as a dedicated piece of hardware such as this. Perhaps we should follow this example. If we did, the Hackaday timer couldn’t possibly use an ESP32.

Half The Reflow Oven You Expected

Toaster oven reflow projects are such a done deal that there should be nothing new in one here in 2025. Take a toaster oven, an Arduino, and a thermocouple, and bake those boards! But [Paul J R] has found a new take on an old project, and better still, he’s found the most diminutive of toaster ovens from the Australian version of Kmart. We love the project for the tiny oven alone.

The brains of the operation is an ESP32, in the form of either a TTGO TTDisplay board or an S3-Zero board on a custom carrier PCB, with a thermistor rather than a thermocouple for the temperature sensing, and a solid state relay to control mains power for the heater. All the resources are in a GitHub repository, but you may have to make do with a more conventionally-sized table top toaster oven if you’re not an Aussie.

If you’re interested, but want a better controller board, we’ve got you covered.

Metal Detector Built With Smartphone Interface

If you think of a metal detector, you’re probably thinking of a fairly simple device with a big coil and a piercing whine coming from a tinny speaker. [mircemk] has built a more modern adaptation. It’s a metal detector you can use with your smartphone instead.

The metal detector part of the project is fairly straightforward as far as these things go. It uses the pulse induction technique, where short pulses are fired through a coil to generate a magnetic field. Once the pulse ends, the coil is used to detect the decaying field as it spreads out. The field normally fades away in a set period of time. However, if there is metal in the vicinity, the time to decay changes, and by measuring this, it’s possible to detect the presence of metal.

In this build, an ESP32 is in charge of the show, generating the necessary pulses and detecting the resulting field. It’s paired with the usual support circuitry—an op-amp and a few transistors to drive the coil appropriately, and the usual smattering of passives. The ESP32 then picks up the signal from the coil and processes it, passing the results to a smartphone via Bluetooth.

The build is actually based on a design by [Neco Desarrollo], who presents more background and other variants for the curious. We’ve featured plenty of [mircemk]’s projects before, like this neat proximity sensor build. Continue reading “Metal Detector Built With Smartphone Interface”