Sneaky Clock Displays Wrong Time If It Catches You Looking

February 23, 2023 by Donald Papp 20 Comments

We have a soft spot for devices that subvert purpose and expectation, and that definitely sums up [Guy Dupont]’s Clock That Is Wrong. It knows the correct time, but whether or not it displays the correct time is another story. That’s because nestled just above the 7-segment display is a person sensor module, and when it detects that a person is looking towards it, the clock will display an incorrect time, therefore self-defeating both the purpose and primary use case of a clock in one stroke.

The person sensor is a tiny board with tiny camera that constantly does its best to determine whether a person is in view, and whether they are looking towards the sensor. It’s a good fit for a project like this, and it means that one can look at the clock from an oblique angle (meaning one is out of view of the sensor) and see the correct time. But once one moves in front of it, the time changes. You can watch a brief video of it in action in this Twitter thread.

One interesting bit is that [Guy] uses an ESP32-based board to drive everything, but had some reservations about making a clock without an RTC. However, he found that simply syncing time over the network every 10 minutes or so using the board’s built-in WiFi was perfectly serviceable, at least for a device like this.

This reminds us a little of other clocks with subtly subversive elements, like the Vetinari Clock which keeps overall accurate time despite irregularly drifting in and out of sync. Intrigued by such ideas? You’re not alone, because there are even DIY hobby options for non-standard clock movements. Adding the ability to detect when someone is looking directly at such a device opens up possibilities, so keep it in mind if it’s time for a weekend project.

Useless Machine Is A Clock

September 14, 2021 by Bryan Cockfield 15 Comments

Useless machines are a fun class of devices which typically turn themselves off once they are switched on, hence their name. Even though there’s no real point, they’re fun to build and to operate nonetheless. [Burke] has followed this idea in spirit by putting an old clock he had to use with his take on a useless machine of sorts. But instead of simply powering itself off when turned on, this useless machine dislodges itself from its wall mount and falls to the ground anytime anyone looks at it.

It’s difficult to tell if this clock was originally broken when he started this project, or if many rounds of checking the time have caused the clock to damage itself, but either way this project is an instant classic. Powered by a small battery driving a Raspberry Pi, the single-board computer runs OpenCV and is programmed to recognize any face pointed in its general direction. When it does, it activates a small servo which knocks it off of its wall, rendering it unarguably useless.

[Burke] doesn’t really know why he had this idea, but it’s goofy and fun. The duct tape that holds everything together is the ultimate finishing touch as well, and we can’t really justify spending too much on fit and finish for a project that tosses itself around one’s room. On the other hand, if you’re looking for a more refined useless machine, we have seen some that have an impressive level of intricacy.

Thanks to [alchemyx] for the tip!

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Retro Useless Clock Eventually Shows You The Time

June 3, 2021 by Kristina Panos 8 Comments

It’s true; hackers like clocks. And hackers like useless machines. But would they like an intersection of the two? We’re thinking yes, probably, though we would argue that this QR clock was at no point fully useless. Yes, a QR clock as in, whip out your phone and, ignoring the conveniently-available phone time, open the bar code reader so you can check the time on this thing. So, it’s semi-useless. But at least it doesn’t detect cameras and then hide the QR code. That would be evil.

This project started life as a display piece for the hex wall down at [megardi]’s hackerspace, but, state of the world being what it is, [megardi] hasn’t made it down there yet. And meanwhile this little guy was looking cuter and cuter, so [megardi] decided to make him more useful and freestanding. The ESP32 inside gets the official time from NIST and displays it on the 1.5″ OLED screen. It also has a single alarm now, along with some other non-QR code clock faces that display the time in various ways.

We really like the look of this clock. Honestly, with those uniform tics around the edge, it sort of reminds us of the doomsday clock — you know, the ‘minutes to midnight’ quarter clock face that shows the current perceived threat level of how close we are to destroying the world with the technologies we’ve created. That clock is kind of cute, too, which is a little bit weird considering what it represents.

Speaking of our delicate planet, here’s a gorgeous little Earth clock that casts a shadow on whatever slice of the planet is currently shrouded in darkness.

Mouse-Controlled Mouse Controller Is Silly, But Could Be Useful

November 29, 2020 by Lewin Day 19 Comments

Useless machines are generally built as a fun pastime, as they do nothing of value by their very definition. The most popular type generally involves a self-cancelling switch. However, there’s plenty of other useless machines to build, and we think [Jeffery’s] build is particularly creative.

The build consists of an XY gantry that moves a standard computer mouse. To control the gantry, a Raspberry Pi feeds the system G-Code relative to the motion of a second mouse plugged into the single-board computer. It’s pretty standard fare overall, with the Pi sending commands to an Arduino that runs the various stepper motors via a CNC controller shield.

Yes, it’s a mouse that moves a mouse – and on the surface, this appears to be a very useless machine. However, we could imagine it being useful for remote control of a very old system that uses a non-standard mouse that is otherwise difficult to emulate. Additionally, it wouldn’t take much extra work to turn the XY gantry into a competent pen-plotter – of which we’ve seen many. Video after the break.

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Finally, A Differently Useless Machine

September 20, 2020 by Kristina Panos 32 Comments

Traditionally, the useless machine is a simple one that invites passersby to switch it on. When they do, the machine somehow, some way, turns itself off; usually with a finger or finger-like object that comes out from the box in what feels like an annoyed fashion. Honestly, that’s probably part of what drives people to turn them on over and over again.

But [Bart Blankendaal] has managed to turn the useless machine on its head. When this machine is switched to the on position, unseen forces inside the box will spin the toggle switch around 180° to the off position.

What’s really happening is that an Arduino is getting a signal from the toggle switch, and is then rotating it on a ball bearing with a stepper motor driven through an H-bridge.

It shouldn’t be too hard to make one of these yourself, given that [Bart] has provided the schematic and STLs. If we weren’t living in such touchy times, we might suggest building one of these into your Halloween candy distribution scheme somehow. Sell the switch as one that turns on a candy dispenser, and then actually dispense it after three or five tries.

Many see useless machines as tangible examples of existential quandary. Here is one that takes that sentiment a bit further by snuffing out a candle.

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Useless Machine For An Existential Quandary

May 27, 2020 by Bryan Cockfield 7 Comments

There’s no project that dives into existential quandaries more than a useless machine, as they can truly illustrate the futility of existence by turning themselves off once they have been powered on. Typically this is done with a simple switch, but for something that can truly put the lights out, and then re-illuminate them, [James]’s latest project is a useless machine that performs this exercise with a candle.

The project consists of two arms mounted on a set of gears. One arm has a lighter on it, and the other has a snuffer mounted to a servo motor. As the gears rotate, the lighter gets closer to the candle wick and lights it, then the entire assembly rotates back so the snuffer can extinguish the flame. Everything is built around an Arduino Nano, a motor driver powering a Pitman gear motor, and a set of Hall effect sensors which provide position data back to the microcontroller.

If you’re in the mood for a little existential angst in your own home, [James] has made the project files available on his GitHub page. We always appreciate a useless machine around here, especially a unique design like this one, and one which could easily make one recognize the futility of lighting a candle at all.

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Slippy Slapper Uselessly Uses All The Arduinos

March 13, 2020 by Kristina Panos 8 Comments

Want to take that annoyingly productive coworker down a notch? Yeah, us too. How dare they get so much done and be so happy about it? How is it possible that they can bang on that keyboard all day when you struggle to string together an email?

The Slippy Slapper is a useless machine that turns people into useless machines using tactics like endless distraction and mild physical violence. It presses your buttons by asking them to press buttons for no reason other than killing their productivity. When they try to walk away, guess what? That’s another slappin’. Slippy Slapper would enrage us by proxy if he weren’t so dang cute.

You’re right, you don’t need an Arduino for this. For peak inefficiency and power consumption, you actually need four of them. One acts as the master, and bases its commands to the other three on the feedback it gets from Slippy’s ultrasonic nostrils. The other three control the slappin’ servos, the speakers, and reading WAV files off of the SD card. Slap your way past the break to see Slippy Slapper’s slapstick demo.

Need to annoy a group of coworkers all at once? Slip a big bank of useless machines into the conference room while it’s being set up.

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