Saving Fuel With Advanced Sensors And An Arduino

August 3, 2022 by 37 Comments

When [Robot Cantina] isn’t busy tweaking the 420cc Big Block engine in their Honda Insight, they’re probably working on some other completely far out automotive atrocity. In the video below the break, you’ll see them take the concept of a ‘lean burn’ system from the Insight and graft hack it into their 1997 Saturn coupe.

What’s a lean burn system? Simply put, it tricks the car into burning less fuel when it’s cruising under a light load to improve the vehicle’s average mileage. The Saturn’s electronics aren’t sophisticated enough to implement a lean burn system simply, and so [Robot Cantina] did what any of us might have done: hacked it in with an Arduino.

The video does a wonderful job going into the details, but essentially by using an oxygen sensor with finer resolution (wide-band) and then outputting the appropriate narrow band signal to the ECU, [Robot Cantina] can fine tune the air/fuel ratio with nothing more than a potentiometer, and the car’s ECU is none the wiser. What were the results? Well… they weren’t as expected, which means more experimentation, more parts, and hopefully, more videos. We love seeing the scientific method put to fun use!

People are ever in the quest to try interesting new (and sometimes old) ideas, such as this hot rod hacked to run with a lawnmower carburetor.

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Maximum Power Point Tracking: Optimizing Solar Panels

August 3, 2022 by 59 Comments

When looking at integrating a photovoltaic solar panel into a project, the naive assumption would be that you simply point the panel into the general direction of where the Sun is, and out comes gobs of clean DC power, ready to be used for charging a battery. To a certain extent this assumption is correct, but feeding a solar panel’s output into something like a regular old PWM buck or boost regulator is unlikely to get you anywhere close to the panel’s full specifications.

The keywords here are ‘maximum power point’ (MPP), which refers to the optimal point on the solar panel’s I-V curve. This is a property that’s important not only with photovoltaics, but also with wind turbines and other highly variable power sources. The tracking of this maximum power point is what is generally referred to as ‘MPPT‘, but within this one acronym many different algorithms are covered, each with its own advantages and disadvantages. In this article we’ll take a look at what these MPPT algorithms are, and when you would want to pick a particular one.

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A Classic TV Trope For An Escape Room

August 3, 2022 by 15 Comments

No spooky mansion is complete without a secret passage accessed through a book shelf — or so Hollywood has taught us. What works as a cliché in movies works equally well in an escape room, and whenever there’s escape rooms paired with technology, [Alastair Aitchison] isn’t far. His latest creation: you guessed it, is a secret bookcase door.

For this tutorial, he took a regular book shelf and mounted it onto a wooden door, with the door itself functioning as the shelf’s back panel, and using the door hinges as primary moving mechanism. Knowing how heavy it would become once it’s filled with books, he added some caster wheels hidden in the bottom as support. As for the (un)locking mechanism, [Alastair] did consider a mechanical lock attached on the door’s back side, pulled by a wire attached to a book. But with safety as one of his main concerns, he wanted to keep the risk of anyone getting locked in without an emergency exit at a minimum. A fail-safe magnetic lock hooked up to an Arduino, along with a kill switch served as solution instead.

Since his main target is an escape room, using an Arduino allows also for a whole lot more variety of integrating the secret door into its puzzles, as well as ways to actually unlock it. How about by solving a Rubik’s Cube or with the right touch on a plasma globe?

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Ultimate Bokeh With A Projector Lens

August 2, 2022 by 22 Comments

Bokeh is a photography term that’s a bit difficult to define but is basically soft, aesthetically pleasing background blur, often used to make a subject stand out. Also called “background separation” or “subject isolation”, achieving it optically requires a fast lens with an aperture below 2.8 or preferably lower. These lenses can get very expensive, but in the video after the break [Matt] from [DIY Perks] blows all the commercially available options out of the water. Using an old episcope projector, he built a photography rig with background separation equivalent to that of a non-existent 35mm f0.4 lens.

Unlike most conventional projectors used to project a prerecorded image, episcopes were used to project an image of physical objects, like books. To use this lens directly in a camera is impossible, due to the size of the imaging circle projected out the back of the lens. At a diameter of 500mm, there is simply no imaging sensor available to capture it. Instead, [Matt] built a projection screen for the image and photographed it from the opposite side with a normal camera.

The projection screen was made by sandwiching a sheet of diffuser film between two sheets of clear acrylic held in a frame of aluminum extrusions. To block out all other light, [Matt] added aluminum shrouds on either side of the screen, which also serves to mount the lens and a camera. The shroud on the lens’ side is mounted on a separate aluminum frame, enabling the image to be focused by adjusting the distance between the screen and lens. Linear rods and bearings on 3D printed mounts allow smooth motion, while a motor-driven lead screw connected to a wired remote does the actual adjustment. The gap between the two halves was covered with bellows made from black paper. Continue reading “Ultimate Bokeh With A Projector Lens” →

Ham Radio Hacking: Thinking Inside The Box

August 2, 2022 by 19 Comments

There are two ways to deal with improving ham radio receivers, or — for that matter — any sort of receiver. You can filter and modify the radio frequency including the radio’s intermediate frequency, or you can alter the audio frequency output. Historically, RF and IF techniques have been the most valued because rejecting unwanted noise and signals early allows the rest of the radio to focus on the actual signal of interest. However, audio filters are much easier to work with and until recently, DSPs that could handle RF frequencies were expensive and uncommon. However, [watersstanton] shows us how to make what could be the cheapest audio enhancer ever. It is little more than a modified cardboard box, and you can see and hear the result in the video below.

On the one hand, you shouldn’t expect miracles. On the other hand, you probably have box laying around and can try it in the next three minutes so why not give it a go? You can hear a bit of difference when using the box and not using the box.

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Tablet ina 3D printed stand, showing timetables on its screen

Revive Your Old E-Ink Tablet For Timetable Helper Duty

August 2, 2022 by 17 Comments

In our drawers, there’s gonna be quite a few old devices that we’ve forgotten about, and perhaps we ought to make them work for us instead. [Jonatron] found a Nook Simple Touch in his drawer – with its E-ink screen, wireless connectivity and a workable Android version, this e-reader from 2011 has the guts for always-on display duty. Sadly, the soft touch covering on the back disintegrated into a sticky mess, as soft touch does, the LiIon battery has gone flat, and the software support’s lackluster. Both of these are likely to happen for a lot of tablets, which is why we’re happy [Jonatron] has shared his story about this e-reader’s revival.

The tablet in question with back cover removed, battery wires connected to a USB cable for powerThe soft touch layer on the back didn’t go away with help of alcohol, but by sheer luck, an acetone bottle was nearby, and an acetone scrub helped get rid of the unpleasant stickiness. The tablet’s charging circuitry turned out to be unsophisticated – the tablet wouldn’t boot from MicroUSB input, and [Jonathan] wired up 5 volts from a USB cable straight into the battery input. Mind you, this might not be advised, as Lithium-Ion battery range is from 3 volts to 4.2 volts and a regulator would be called for, but [Jonatron] says it’s been working just fine.

Usually, you could just put a webserver on your local network and serve a page with useful information, adding code to refresh the page periodically – but the Nook’s browser didn’t support automatic refreshes. Not to be stopped, [Jonatron] wrote an app for the Nook’s Android install instead; rooting was required but went seamlessly. The Android install is old, and Android Studio for it is no longer downloadable, so he used an older development toolkit somehow still available online. There’s still a small Python-written webserver running on a spare Pi, conditioning the data for the app to fetch. Following best hacker traditions, both the app and the server are open-sourced! With help of a 3D printed stand, this tablet now displays train departure schedules – perfect application for an old e-reader like this.

Got a Nook Simple Touch in a drawer? Now you know you can easily convert it into a hackable E-ink display! We’ve seen numerous tablet restorations before, replacing charger ICs and eMMC drives, turning them into videophones to chat with our relatives and smart home controllers, and there’s even repair databases to help you in your revival efforts. We’ve been getting quite a few projects like these in our last Hackaday Prize installment, Hack It Back, and we hope to see more such rebuilds for our Wildcard round!