It looks like an ordinary toolbox, but when you open up the Arduino Launch Control System, you’ll find a safe method for triggering model rocket launches. The system uses two separate power supplies. Both must be on for a successful launch and one requires a key. To trigger a 10-second countdown, the operator must hold down two buttons. Releasing either button will stop the countdown.

Besides safety, the controller tracks mission elapsed time and can read weather information from a few sensors. A good-looking build and we like the idea of building inside a toolbox for this sort of thing.

Towards the end of the post, there are some ideas for improving the build, like using a consolidated weather sensor, using a larger screen, and a bigger, more capable controller. It seems like more I/O would be useful,

Model rocketry isn’t as rigorous as launching a crew, but there were a few things that could improve the overall system safety. For example, the launch buttons could provide both normally open and normally closed contacts to guard against switch failure. In other words, if you see both inputs from one switch on or off for more than a tiny moment during switching, you can assume the switch has failed and put the system in a fail-safe mode. Of course, a switch failure in the off position isn’t a hazard, just an inconvenience. But a switch failure in the active position could allow an inadvertent launch. Granted, it would require something jamming the remaining switch for the entire 10-second countdown, but still. Arduinos are pretty reliable, but for a real rocket system, you’d probably have redundancy, and the software would do periodic checks to guard against things like memory corruption.  For example, NASA has a relatively succinct list of requirements. But some of this is overkill for a model rocket launcher.

We’ve seen many takes on this kind of project. Of course, like everything else these days, you can just use your smartphone.

If you’ve been pining for a retro-chic 16×2 LCD display to enhance your Windows computing experience, then [mircemk] has got you covered with their neat Windows-based LCD Info Panel.

Your everyday garden variety Arduino is the hero here, sitting between the computer’s USB port and the display to make the magic happen. Using the ‘LCD Smartie‘ software, the display can serve up some of your typical PC stats such as CPU and network utilization, storage capacity etc. It can also display information from BBC World News, email clients, various computer games and a world of other sources using plugins.

It’s clear that the intention here was to include the display inside your typical PC drive bay, but as you can see in the video below, this display can just about fit anywhere. It’s not uncommon to see similar displays on expensive ‘gamer’ peripherals, so this might be an inexpensive way for someone to bring that same LED-lit charm to their next PC build. You probably have these parts sitting in your desk drawer right now.

If you want to get started building your own, there’s more info over on the Hackaday.io page. And if PC notifications aren’t your jam, it’s worth remembering that these 16×2 displays are good for just about anything, like playing Space Invaders.

[Duncan McIntyre] lives in the UK but participated in a secret Santa gift exchange for his Dutch friends’ Sinterklaas celebration. In traditional maker fashion, [Duncan] went overboard and created a miniature gym gift box, complete with flashing lights, music and a motorized lid.

[Duncan] used [TanyaAkinora]’s 3D printed tiny gym to outfit the box with tiny equipment, with a tiny mirror added to round out the tiny room. An ATmega328P was used as the main microcontroller to drive the MP3 player module and A4988 stepper motor controller. The stepper motor was attached to a drawer slide via a GT2 timing belt and pulley to actuate the lid. Power is provided through an 18V, 2A power supply with an LM7805 providing power to the ATmega328P and supporting logical elements. As an extra flourish, [Duncan] added some hardware audio signal peak detection, fed from the speaker output, which was then sampled by the ATmega328P to be able to flash the lights in time with the playing music. A micro switch detects when the front miniature door is opened to begin the sequence of lights, song and lid opening.

[Duncan] provides source on GitHub for those curious about the Arduino code and schematics. We’re fans of miniature pieces of ephemera and we’ve featured projects ranging from tiny 3D printed tiny escalators to tiny arcade cabinets.

Video after the break!

There comes a point in every Arduino’s life where, if it’s lucky, it becomes a permanent fixture in a project. We can’t think of too many better forever homes for an Arduino than inside of a 3D-printed synthesizer such as this 17-key number by [ignargomez] et al.

While there are myriad ways to synthesizer, this one uses the tried-and-true method of FM synthesis courtesy of an Arduino Nano R3. In addition to the 17 keys, there are eight potentiometers here — four are used for FM synthesis control, and the other four are dedicated to attack/delay/sustain/release (ADSR) control of the sound envelope.

One of the interesting things here is that [ignargomez] and their team were short a few regular pots and modified a couple of slide pots for circular use — we wish there was more information on that. As a result, the 3D printed enclosure underwent several iterations. Be sure to check out the brief demo after the break.

Don’t have any spare Arduinos? The BBC Micro:bit likes to make noise, too.

For those unfamiliar with the details of the expansive work of fiction of Harry Potter, it did introduce a few ideas that have really stuck in the collective conscious. Besides containing one of the few instances of time travel done properly and introducing a fairly comprehensive magical physics system, the one thing specifically that seems to have had the most impact around here is the Weasley family clock, which shows the location of several of the characters. We’ve seen these built before in non-magical ways, but this latest build seeks to drop the price tag on one substantially.

To do this, the build relies on several low-cost cloud computing solutions and smartphone apps to solve the location-finding problem. The app is called OwnTracks and is an open-source location tracker which can report data to any of a number of services. [Simon] sends the MQTT data to a cloud-based solution called HiveMQCloud, but you could send it anywhere in principle. With the location tracking handled, he turns to some very low-cost Arduinos to control the stepper motors which point the clock hands to the correct locations on the face.

While the build does rely on a 3D printer for some of the internal workings of the clock, this does bring the cost down substantially when compared to other options. Especially when compared to this Weasley family clock which was built into a much larger piece of timekeeping equipment, having an option for a lower-cost location-tracking clock face like this one is certainly welcome.

Even though some devices now use WiFi and Bluetooth, so much of our home entertainment equipment still relies on its own proprietary infrared remote control. By and large (when you can find them) they work fine, but what happens when they stop working?  First port of call is to change the batteries, of course, but once you’ve tried that what do you do next? [Hulk] has your back with this simple but effective IR Remote Tester / Decoder.

By using a cheap integrated IR receiver/decoder device (the venerable TSOP4838), most of the hard work is done for you! For a quick visual check that your remote is sending codes, it can easily drive a visible LED with just a resistor for a current-limit, and a capacitor to make the flickering easier to see.

For an encore, [Hulk] shows how to connect this up to an Arduino and how to use the “IRremote” library to see the actual data being transmitted when the buttons are pressed.

It’s not much of a leap to imagine what else you might be able to do with this information once you’ve received it – controlling your own projects, cloning the IR remote codes, automating remote control sequences etc..

It’s a great way to make the invisible visible and add some helpful debug information into the mix.

We recently covered a more complex IR cloner, and if you need  to put together a truly universal remote control, then this project may be just what you need.

With surface-mount components quickly becoming the norm, even for homebrew hardware, the resistor color-code can sometimes feel a bit old-hat. However, anybody who has ever tried to identify a random through-hole resistor from a pile of assorted values will know that it’s still a handy skill to have up your sleeve. With this in mind, [j] decided to super-size the color-code with “The Great Resistor”.

At the heart of the project is an Arduino Nano clone and a potential divider that measures the resistance of the test resistor against a known fixed value. Using the 16-bit ADC, the range of measurable values is theoretically 0 Ω to 15 MΩ, but there are some remaining issues with electrical noise that currently limit the practical range to between 100 Ω and 2 MΩ.

[j] is measuring the supply voltage to help counteract the noise, but intends to move to an oversampling/averaging method to improve the results in the next iteration.

The measured value is shown on the OLED display at the front, and in resistor color-code on an enormous symbolic resistor lit by WS2812 RGB LEDs behind.

Precision aside, the project looks very impressive and we like the way the giant resistor has been constructed. It would look great at a science show or a demonstration. We’re sure that the noise issues can be ironed out, and we’d encourage any readers with experience in this area to offer [j] some tips in the comments below. There’s a video after the break of The Great Resistor being put through its paces!

If you want to know more about the history of the resistor color code bands, then we have you covered.  Alternatively, how about reading the color code directly with computer vision?

How many of us have an everyday tool that’s truly unique? Likely not many of us; take a look around your desk and turn out your pockets, but more often than not, what you’ll find is that everything you have is something that pretty much everyone else on the planet could have bought too. But not so if you’ve got this beautiful custom RPN calculator in a wooden case.

This one comes to us from [Shinsaku Hiura], who generally dazzles us with unique mechanical clocks and displays. This calculator solves a more practical problem — the dearth of RPN calculators on the market with the correct keyboard feel, specifically with the large keys and light touch he desired. Appropriately, the build started with a numeric keypad, which once liberated of its USB interface was reverse-engineered to figure out how the matrix was wired. Next up, a custom PCB to connect the keypad to an Arduino and a 20×4 LCD display was milled up, while a test case was designed and printed to check fitment. The final case was milled from a block of solid walnut and fitted with an acrylic window, for a sharp look with clean lines and pleasing colors.

As for the calculator itself, the demo below shows it going through its paces. The code is clever because it leverages the minimal number of keys available by hiding all the scientific and engineering functions behind a “secret silver key” that was once the equals key and obviously not needed in RPN. Hats off to [Shinsaku] for a handsome and unique addition to his desk.

For British kids of a certain age, their first experience of a computer was very likely to have been in front of a Sinclair ZX81. The lesser-known predecessor to the wildly-successful ZX Spectrum, it came in at under £100 and sported a Z80 processor and a whopping 1k of memory. In the long tradition of Sinclair products it had a few compromises to achieve that price point, the most obvious of which was a 40-key membrane keyboard. Those who learned to code on its frustrating lack of tactile feedback may be surprised to see an Arduino project presenting it as the perfect way to easily hook up a keyboard to an Arduino.

Like many retrocomputing parts, the ZX81 ‘board has been re-manufactured, to the joy of many a Sinclair enthusiast. It’s thus readily available and relatively cheap (we think they can be found for less than the stated 20 euros!), so surprisingly it’s a reasonable choice for an Arduino project. The task of trying to define by touch the imperceptible difference in thickness of a ZX81 key will bring a true retrocomputing experience to a new generation. Perhaps if it can be done on an Mbed then someone might even make a ZX81 emulator on the Arduino.

We’re great fans of the ZX81 here at Hackaday, for some of us it was that first computer. Long may it continue to delight its fans!

Input devices that can handle rough and tumble environments aren’t nearly as varied as their more fragile siblings. [Alastair Aitchison] has devised a brilliant way of detecting inputs from plumbing valves that opens up another option. (YouTube) [via Arduino Blog]

While [Aitchison] could’ve run the plumbing valves with water inside and detected flow, he decided the more elegant solution would be to use photosensors and an LED to simplify the system. This avoids the added cost of a pump and flow sensors as well as the questionable proposition of mixing electronics and water. By analyzing the change in light intensity as the valve closes or opens, you can take input for a range of values or set a threshold for an on/off condition.

[Aitchison] designed these for an escape room, but we can see them being great for museums, amusement parks, or even for (train) simulators. He says one of the main reasons he picked plumbing valves was for their aesthetics. Industrial switches and arcade buttons have their place, but certainly aren’t the best fit in some situations, especially if you’re going for a period feel. Plus, since the sensor itself doesn’t have any moving parts, these analog inputs will be easy to repair should anything happen to the valve itself.

If you’re looking for more unusual inputs, check out the winners of our Odd Inputs and Peculiar Peripherals contest or this typewriter that runs Linux.