Arduino Rig Does Spectrophotometry

August 24, 2020 by Zoe Skyforest 13 Comments

Spectrophotometry is an important scientific tool, most commonly used in biology and chemistry. It’s a method to measure the amount of light absorbed by a chemical solution at various different wavelengths. While it’s typically the preserve of expensive lab equipment, [Daniel Hingston] built a rig to do the job at home.

The heart of the rig is a normal filament-based flashlight bulb, which produces good-quality white light containing all colors. A prism is then used to split the light into its component wavelengths, so that the sample can be tested across the whole light spectrum. The prism is rotated by a servo motor, which exposes the sample to the full rainbow, while an Arduino uses a light-dependent resistor to measure how much light makes it through the sample. Thus, the amount of light absorbed by the sample can be calculated, relative to calibrations made with no sample present.

It’s a simple build that can be achieved with fairly common materials, barring the prism which may need to be specially ordered. It would be a great way to teach highschool students about advanced scientific concepts, as well as showing them behind the curtain of how lab equipment works.

We see all kinds of DIY science gear around here; this lantern-based bioreactor is a great example. Video after the break.

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Manual Larson Scanner Invites You To Crank It

August 22, 2020 by Zoe Skyforest 12 Comments

Hasselhoff make Larson Scanners famous. That’s the name for the scanning red lights on the front of KITT, the hero car from the popular 1980s TV series Knight Rider. Despite serving a solely aesthetic role, they remain a fun and popular LED project to this day. Putting a new twist on the old concept, [Pete Prodoehl] whipped up a Larson Scanner that you crank to operate.

Built out of LEGO, the project relies on a hand crank to work. The crank turns a drum, onto which is placed several strips of conductive Maker Tape – a steel/nylon material which we’ve looked at before. Strips of tape running side-by-side are bridge by segments of tape on the drum as it turns. The LEDs are switched on in the requisite pattern of a traditional Larson scanner.

The project has inspired further possibilities, such as using similar techniques to produce an electronic music box or player piano that will change tempo as the user changes the speed with the crank. [Pete] notes that turning the crank is an inherently enjoyable experience, and given the wonder inherent in hand-cranked musical projects like Marble Machine X, we can’t wait to see where this one goes next. Video after the break.

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Get Creative With This ESP8266 Photography Light

August 21, 2020 by Zoe Skyforest 10 Comments

In today’s fast-paced world of social media, if you want your photos to grab attention, you’ve got to have an edge. Whether it’s a deft touch in Photoshop or an amazing lens, it’s important to stand apart. Another great way is to experiment with lighting and color. To do just that, [Andrei] built a pocket RGB photo light for the home studio.

This is a project that any experienced maker should be able to whip up in a weekend. Not that there’s anything wrong with that, of course. The basic enclosure is 3D printed and readily reproducible on any FDM printer. Lighting is provided via the venerable WS2812B LED, 68 of them, to be exact. Finally there’s an ESP8266 running WLED, a webserver for the platform that’s dedicated to controlling LED strips. This makes it easy to tweak the LEDs with your smartphone.

Thanks to the WS2812Bs LEDs, a full range of RGB colors are available for [Andrei] to experiment with. He’s done a great job showing off the light with a few choice cat pics that serve to show its capabilities. While we wouldn’t expect to use such a device for clean white lighting in a serious photographic sense, it’s a perfect tool for art photography.

We’ve covered other studio light builds before, too. Video after the break.

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How To Get Into Cars: Aero Mods For More Grip

August 19, 2020 by Zoe Skyforest 32 Comments

In 1960, Enzo Ferrari said “Aerodynamics are for people who can’t build engines”. It’s a quote that’s been proven laughably wrong in decades since. Aerodynamics are a key consideration for anyone serious about performance in almost any branch of motorsport. Today, we’ll take a look at how aero influences the performance of your car, and what modifications you might undertake to improve things.

Gains To Be Had

Improving the aerodynamics of your vehicle can mean wildly different things, depending on what your end goal is. Aerodynamics affects everything from top speed, to fuel economy, to grip, and optimizing for these different attributes can take wildly different routes. Often, it’s necessary to find a balance between several competing factors, as improvements in one area can often be detrimental in another.

To understand aerodynamics with regards to cars, we need to know about the forces of lift (or downforce), and drag. Drag is the force that acts against the direction of motion, slowing a vehicle down. Lift is the force generated perpendicular to the direction of motion. In the context of flight, the lift force is generated upwards with respect to gravity, lofting planes into the air. In an automotive context, we very much prefer to stay on the ground. Wings and aerodynamic surfaces on cars are created to create lift in the opposite direction, pushing the vehicle downwards and creating more grip. We refer to this “downwards lift” as downforce.

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Airlines Seek Storage For Grounded Fleets Due To COVID-19

August 19, 2020 by Zoe Skyforest 58 Comments

Ask any airline executive what their plans were back in January 2020, and you’d probably get the expected spiel about growing market share and improving returns for shareholders. Of course, the coronovirus pandemic quickly changed all that in the space of just a few months. Borders closed, and worldwide air travel ground to a halt.

Suddenly, the world’s airlines had thousands of planes and quite literally nowhere to go. Obviously, leaving the planes just sitting around in the open wouldn’t do them any good. So what exactly is involved in mothballing a modern airliner?

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Model Railroad Engine Gets A Tiny OLED Rollsign While Showing Off Tidy Protoboard Skills

August 19, 2020 by Zoe Skyforest 4 Comments

When catching public transport, it’s very helpful if the bus or train in question has a large display indicating the route or destination. While many transit lines now rely on flipdot or LED displays, the classic rollsign still gets the job done. [diorama111] wanted to emulate this on a model railroad, and set about building a simulacrum at tiny scale.

Intended to suit an HO-scale model train, the build makes use of a tiny 0.6 inch NHD-0.6-6464G OLED display. It’s wired up with a boost converter for power and hooked up to a tiny circuit consisting of an ATMEGA328p and an infrared receiver. The microcontroller is responsible for receiving commands from the remote control, and displaying the appropriate image on the screen. The hidden beauty of this one is well shown in the video below as [diorama111] cleanly and meticulously assembles the circuit on protoboard with just an iron and tweezers.

What makes this project great is how neatly it’s integrated into the body of the train. Nestled inside the locomotive, it almost looks like a stock part of the model. While the nature of the OLED display does come across a touch anachronistic, implementing the vertical scroll really does add a lot to the final effect.

We love to see creative scale modelling projects, and we’ve seen some great work from [diorama111] in the past, too. Video after the break.

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Restoring Commodore’s Unloved Plus/4

August 18, 2020 by Zoe Skyforest 9 Comments

The Commodore Plus/4 was not loved by the marketplace after its launch in 1984. Despite its namesake feature of having productivity programs built in, its lack of compatibility with Commodore 64 software and oddball status meant that it struggled to find acceptance. However, like so many retro computers, it maintains a following to this day. [Drygol] had collected a total of eight neglected units, and set to giving them a full workover.

First on the docket is cleaning, and [Drygol] makes short work of disassembling the computers and removing decades of dirt and dust. Keycaps are treated with Retrobright to restore their original color. The black styling of the case means it gets a simple wash down instead, and then a rub with thin oil to restore the plastic’s original sheen.

[Drygol] steps through various popular hacks for the platform too, from 6510 CPU replacements for the often-failing 7501 and 8501, to SD2IEC card interfaces to replace the much-maligned storage original storage options. Damaged keyboard studs are replaced with hacked-up Amiga parts, while LEDs that are long out of production are swapped out for cut-down modern parts.

The impressive thing is just how much community support there is for an also-ran Commodore that never truly caught the public’s eye. Efforts are ongoing, too, with projects like THED aiming to reproduce some of the custom chips used on the platform.

We’ve featured posts on the engineering that goes into Commodore’s 8-bit computers as well, like this excellent piece from [Bil Herd] on the story of the Commodore 128. Of course, if you’re working your own wonders with retro hardware, you know who to call.