ReMarkable Tablet Scores A MicroSD Slot

August 30, 2019 by Zoe Skyforest 4 Comments

There’s been a marked trend towards modern tablets and phones having fewer expansion options. It’s becoming rarer to find a microSD slot available, which can be particularly frustrating. For [davisr], this simply wouldn’t do, and they set about hacking their ReMarkable tablet.

A rotary tool was used to make a tidy slot for the microSD card.

The ReMarkable already has a set of pads for an SDHC interface on the main board, ready to go. Despite this, both hardware and software modifications are required to get things up and running. [davisr] started by soldering some wires to the main board, feeding them to a microSD socket, which was mounted on the edge of the tablet in a convenient nook. The case was then delicately modified to make a slot for cards to be inserted and removed. With this done, the kernel was then recompiled to enable support for the SDHC interface, and everything was up and running.

With the modification in place, [davisr] now has over 150GB of storage available, which should last for quite some time. Similar hacks are possible on other platforms, too. Even the Pi Zero can mount a second SD card with the right mods!

Measuring Particulate Pollution With The ESP32

August 29, 2019 by Zoe Skyforest 7 Comments

Air pollution isn’t just about the unsightly haze in major cities. It can also pose a major health risk, particularly to those with vulnerable respiratory systems. A major part of hazardous pollution is particulate matter, tiny solid particles suspended in the air. Particulate pollution levels are of great interest to health authorities worldwide, and [niriho] decided to build a monitoring rig of their own.

Particulate matter is measured by an SDS011 particulate matter sensor. This device contains a laser, and detects light scattered by airborne particles in order to determine the level of particulate pollution in PM2.5 and PM10 ranges. The build makes use of an ESP32 as the brains of the operation, chosen for its onboard networking hardware. This makes remotely monitoring the system easy. Data is then uploaded to a Cacti instance, which handles logging and graphing of the data.

For those concerned about air quality, or those who are distrustful of official government numbers, this build is a great way to get a clear read on pollution in the local area. You might even consider becoming a part of a wider monitoring network!

Experiments In 3D Graphics Via Excel

August 29, 2019 by Zoe Skyforest 10 Comments

3D graphics were once the domain of university research groups and large, specialized computing systems. Eventually, they were tamed and became mainstream. Your phone, tablet, and home computer are all perfectly capable of generating moving 3D graphics. Incidentally, so is Microsoft Excel.

This is the work of of [s0lly], who has been experimenting wtih Excel in this way for quite some time. Starting with pseudo-3D graphics, the project then progressed to the development of a real 3D engine. Naturally, things couldn’t stop there. The next logical step was to advance to raytracing, which was pulled off with aplomb. Shiny spheres on featureless planes are par for the course here.

The graphics are necessarily basic, with resolutions on the order of 256×144. Output is by changing the individual color of the various cells of the spreadsheet. The relevant files are available on Github, for those eager to tinker with experiments of their own. We’ve seen others attempt similar work before, with [C Bel] writing a full game engine for the platform. Video after the break.

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Cat Litter Tray Joins The Internet Of Things

August 28, 2019 by Zoe Skyforest 25 Comments

Keeping a cat as a pet can be rewarding, but it’s always important to consider how to handle the mess – and we’re not just talking about the tea cups pushed off tables here. To handle just this task, [Igor] decided to hook his cat litter box up to the internet of things.

Monitoring the litter box brings several useful advantages. Load cells enable the weight of the litter tray to be monitored, allowing sand levels and the weight of the cats to be checked at regular intervals. Additionally, a door sensor keeps a record of comings and goings, giving an idea of how frequently the box has been used, and whether or not it may be time for cleaning. It’s all powered by an ESP32, hooked up to the Thingspeak platform. This allows for easy graphing and analysis of the data collected from the system. The electronics is then neatly installed in an attractive two-tone 3D printed enclosure with a pleasing cat motif.

It’s a great example of using some cheap off-the-shelf parts to ease the regular tasks of daily life. Building your own gear can be beneficial too, especially when Big Litter implements DRM on their hardware.

Global Radiation Montoring And Tracking Nuclear Disasters At Home

August 28, 2019 by Zoe Skyforest 10 Comments

Many of us don’t think too much about radiation levels in our area, until a nuclear disaster hits and questions are raised. Radiation monitoring is an important undertaking, both from a public health perspective and as a way to monitor things like weapon development. So why is it done, how is it done, and what role can concerned citizens play in keeping an eye on things?

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The Trials And Tribulations Of E-Bike Drivetrain Design

August 26, 2019 by Zoe Skyforest 32 Comments

[Tom Stanton] is well-regarded in the maker community, and has put much effort in over the years on a variety of electric vehicle builds. In the process of upgrading his e-bike last year, he ran into some issues with the main drive pulley. Rather than rely on guesswork, he threw engineering at the problem.

Static weight tests were carried out in combination with FEA to determine the root cause of the problem.

The problem concerned the mounting bolts on the pulley’s hub, which would pull out under high torque. [Tom’s] initial finite element simulations had suggested the design was sound, but reality was proving otherwise. After further analysis and testing, [Tom] determined that his analysis hadn’t properly simulated the bolt pull-out condition. With this corrected in the software, it was readily apparent that there simply wasn’t enough material around the bolt holes to hold the torque load.

With the simulation now more closely agreeing with reality, [Tom] was able to correct the design. New parts were created with a strengthened mounting section, and the pulley was successfully able to deal with the loads in service.

It’s a great example of using engineering simulation tools to solve a problem quickly, rather than simply guessing and hoping things will hold up. We’ve seen [Tom]’s work before, too — like this fun backyard trebuchet build. Video after the break.

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NES Gets A Slick Acrylic Casemod

August 25, 2019 by Zoe Skyforest 9 Comments

Those alive during the 1990s will remember the clear or “crystal” versions of various home consoles. Made with the usual injection molding processes, they usually came out somewhere closer to a smoky translucency and didn’t reveal much of the insides. [BitHead1000] likes to do things right though, and has busted out an awesome acrylic case mod for his NES.

The build starts with the disassembly of the original console, naturally, and the RF shielding is discarded in order to provide an unobstructed view of the internals. The acrylic case is then built up piece by piece, using the original case as a template. Flame polishing is used to treat the edges, and everything is stuck together using what appears to be acrylic cement. For a nice finishing touch, the cartridge door gets a frosted Nintendo logo, thanks to some careful work in the sandblasting booth.

The final product looks stunning, and the transparent case lends itself excellently to edge-lighting thanks to a few LEDs. We’ve seen [BitHead1000’s] work before, with the stunning flamethrowing N64 build. Video after the break.