Why Won’t This Darn Thing Charge?

What is more fun than plugging in your phone and coming back to find your battery on empty? Stepping on a LEGO block with bare feet or arriving hungry at a restaurant after closing probably qualify. [Alex Sidorenko] won’t clean your floors or order you a pizza, but he can help you understand why cheap chargers won’t always power expensive devices. He also shows how to build an adapter to make them work despite themselves.

The cheapest smart device chargers take electricity from your home or car and convert it to five volts of direct current. That voltage sits on the power rails of a USB socket until you plug in a cable. If you’re fortunate, you might get a measly fuse.

Smart device manufacturers don’t make money when you buy an off-brand charger, and they can’t speak to the current protection of them, so they started to add features on their own chargers to protect their components and profit margins. In the case of dedicated chargers, a simple resistor across the data lines tells your phone it is acceptable power. Other devices are more finicky, but [Alex Sidorenko] shows how they work and provides Eagle files to build whatever flavor you want. Just be positive that your power supply is worthy of the reliability these boards promise to the device.

Now you know why connecting a homemade benchtop power supply to a USB cable seems good on paper but doesn’t always get the job done. Always be safe when you make your own power supplies.

IoT Doorman: Eye-Controlled Door for a Girl with Cerebral Palsy

Kyleigh has an eye-controlled computer on her wheelchair but something as simple as her bedroom door was still beyond her reach… until now! [Bill Binko], recently filmed a demo of an automatic, IoT door opener built for the young girl with cerebral palsy. [Bill] is a co-founder of ATMakers, an organization that enables makers interested in assistive technologies to collaborate with users to improve quality of life.

Using her eye tracking tablet (PRC Device), Kyleigh has two new icons that make the relevant call to a website, pushing a simple command to either open or close her bedroom door. The device attached to the door uses an Adafruit M0 WiFi Feather board, a DC stepper motor and wheel, a UBEC buck converter, and a potentiometer.

Since other family members are also going to be opening and closing the door, there’s potentiometer which measures the door position for proper operation next time Kyleigh wishes to use the door. The installation also maintains a fairly inconspicuous profile for the assistance it gives — the ‘brain’ is enclosed in a small box on the door, with the motor only slightly larger on the door’s base.

[Bill] believes the project has a few quibbles and wants to work out a smaller wait before the open/close process is executed and optimizing the open/close speed. You have to check out the video below to see that it works really really. We’re also excited to see Kyleigh using her gaze control to talk to an Amazon Echo. [Bill] foresee a door control improvement that links it to Alexa. And how much did it cost to improve the quality of life for this young girl? $70.

We love seeing makers help people, and cannot wait to see what 2018 will bring! If you’re looking for more inspiration, don’t miss the eye-controlled wheelchair project called Eyedrivomatic which won the 2015 Hackaday Prize. There’s also the top Assistive Technology projects from the Hackaday Prize.

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Inexpensive Display Jumps to Life

If you’ve ever been to a local fair or amusement park, chances are you’ve seen an illusion known as Pepper’s Ghost. To perform the illusion, essentially all that’s needed is a thin sheet of plastic or one-way mirror and a light source. Get it right, and you’ll have apparitions popping up in all kinds of interesting places. With just the right software, though, one of those places could be in your own 3D display.

Using just a tablet and a sheet of plastic rolled into a cone, a three-person team was able to create a 3D display using the Pepper’s Ghost illusion. Using special software that the team developed, an image is altered so that when it reflects off of the plastic cone the image appears as a 3D rendering of the original picture. The rendering is perspective-correct and offers a novel way to interact with a 3D model without needing expensive equipment or special glasses.

If you do have some fancy equipment sitting around, like a computer monitor and some plexiglass, similar 3D displays have been made which utilize similar effects. Right now the team that developed this one haven’t made their code open yet, but have promised to release it soon so that others can build their own displays.

Thanks to [bmsleight] for the tip!

Tricked-Out Tablet Becomes Workbench Tool

The workbench of the typical electronics hobbyist today would probably be largely recognizable by Heathkit builders back in the 60s and 70s. But where the techs and tinkerers of yesteryear would have had a real dead-tree SAMS Photofact schematic spread out on the bench, today you’ll get more use out of a flat-screen display for data sheets and schematics, and this handy shop Frankentablet might be just the thing to build.

Tablets like the older Nexus 9 that [enginoor] used as the basis for this build have a little bit of a form-factor problem because unlike a laptop, a tablet isn’t very good at standing up on its own. To fix that, they found a suitable silicone skin for the Nexus, and with some silicone adhesive began bedazzling the back of the tablet. A bendy tripod intended for phones was added, and with the tablet able to stand on its own they maximized the USB port with a right angle adapter and a hub. Now the tablet has a USB drive, a mouse, and a keyboard, ready for perusing data sheets online. And hackers of a certain age will appreciate the eyeball-enhancing potential of the attached USB microscope.

[enginoor]’s bench tablet is great, but we’ve seen full-fledged bench PCs before too. Take your pick — wall mounted and floating, or built right into the workbench.

Thanks to [ccvi] for the tip.

Hybrid Interface Brings Touchscreen to Rigol Scope

With pervasive smartphones and tablets, the touch interface is assumed for small LCD screens, and we’ve likely all poked and pinched at some screen, only to find it immune to our gestures. Manufacturers have noticed this and begun adding touch interfaces to instruments like digital oscilloscopes, but touch interfaces tend to be an upgrade feature. But thanks to this hybrid oscilloscope touchscreen interface, even the low-end scopes can get in on the action.

It only makes sense that [Matt Heinz] started with one of the most hackable scopes for this build, which was his Master’s thesis project. Using an Android tablet as an auxiliary interface, [Matt] is able to control most of the main functions of the scope remotely. Pinching and expanding gestures are interpreted as horizontal and vertical scaling, while dragging the displayed waveform changes its position and controls triggering. While it’s not a true touchscreen scope, the code is all open source, so can a true aftermarket Rigol touchscreen be far away?

Rigol hacks abound here — you can talk to them in Linux, increase the bandwidth, or just get a look at their guts.

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Huge Functionality, Small Package: A Custom Tablet, Raspberry Style

As the adage goes, “if you want something done right, do it yourself.” Desirous of a tablet but preferring to eschew consumer models, [Stefan Vorkoetter] constructed his own compact and lightweight Raspberry Pi tablet, covering several extra miles in the process.

The tablet makes use of a Raspberry Pi 3 and the official touchscreen, with the final product marginally larger than the screen itself. Designed with a ‘slimmer the better’ profile in mind, [Vorkoetter] had to modify several components to fit this precept; most obvious of these are the removal of the Pi’s GPIO headers, USB, and Ethernet ports, and removing the USB power out port from the touchscreen controller board so the two could be mounted side-by-side.

An Adafruit PowerBoost 1000C handles charging the 6200 mAh battery — meaning up to six hours(!) of YouTube videos — via a micro USB, but only after [Vorkoetter] attached a pair of home-made heatsinks due to negligible air flow within the case. A modified USB audio adapter boosts the Pi’s audio capabilities, enabling the use of headphones, a mic, and a built-in speaker which is attached to the tablet’s back cover.

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Homemade Subaru Head Unit is Hidden Masterpiece

The Subaru BRZ (also produced for Toyota as the GT86) is a snappy sportster but [megahercas6]’s old US version had many navigation and entertainment system features which weren’t useful or wouldn’t work in his native Lithuania. He could have swapped out the built in screen for a large 4G Android tablet/phone, but there’s limited adventure in that. Instead, he went ahead and built his own homemade Navigation system by designing and integrating a whole bunch of hardware modules resulting in one “hack” of an upgrade.

The system is built around a Lenovo 4G phone-tablet running android and supporting GPS, GLONASS as well as the Chinese BeiDou satellite navigation systems. He removed the original daughter board handling the USB OTG connection on the tablet, and replaced it with his version so he could connect it to his external USB board via a flat ribbon cable. The USB board contains a Cypress 4-port USB hub. One port is used as the USB HID device to allow external buttons for system control — Power, Volume Up/Down, Fwd/Rev, Play/Pause, and Phone Answer/Hangup. The second port is used as a regular USB input to allow connecting external devices such as flash drives. The third one goes to a reversing camera while the fourth port goes to a USB DAC.

The USB DAC is another hardware board by itself and also includes a Bluetooth module which integrates his phone’s audio and control functions with the on-board system. There’s also an audio mixer which allows him to use the phone audio without having to miss out on the navigation prompts from the tablet. Both boards also contain several peripheral circuits such as amplifiers and DC power supplies. Audio to the speakers is routed through six LM3886 based power amplifier boards. And the GPS module receives its own special low-noise amplifier board to ensure extremely strong reception at all times. That’s a total of ten boards custom built for this project. He’s also managed to source all the original harness connectors so his system is literally a snap in replacement. The final assembly looks pretty dashing.

For some strange reason, the Lenovo tablet uses 4.35V as the ‘fully charged” value for its LiPo instead of the more common 4.20V, so even with the whole system connected to a hefty 12V lead acid battery from which he’s deriving the 4.20V charging voltage for the tablet, it still complains about “low battery” — and he’s looking for advice on how he can resolve that issue short of blowing up the LiPo by using the higher charge voltage. Besides that, he’s (obviously a kickass) hardware designer and a little bit rusty on the software and programming side of things, for which he’s looking for inputs from the community. His introductory video is almost 30 minutes long, but the shorter demo video after the break shows the system after installation in his car. He’s posted all of his Altium hardware source files on the project page, but until he shares PDF versions, it would be difficult for most of us to look at his work.

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