DIYing A VR Headset For Cheap

June 2, 2020 by Zoe Skyforest 18 Comments

VR has been developing rapidly over the past decade, but headsets and associated equipment remain expensive. Without a killer app, the technology has yet to become ubiquitous in homes around the world. Wanting to experiment without a huge investment, [jamesvdberg] whipped up a low-cost headset for under $100 USD.

The build relies on Google-Cardboard-style optics, which are typically designed to work with a smartphone as the display. Instead, an 800×480 display intended for use with the Raspberry Pi is installed, hooked up over HDMI. An MPU6050 IMU is then installed to monitor the headset’s movements, hooked up to an Arduino Micro that passes this information to the attached PC. The rest of the build simply consists of cable management and power supply to all the hardware. It’s important to get this right, so that one doesn’t get tangled up by the umbilical when playing.

While it won’t outperform a commercial unit, the device nevertheless offers stereoscopic VR at a low cost. For a very cheap and accessible VR experience that’s compatible with the PC, it’s hard to beat. Others have done similar work too. Video after the break.

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Credit Card Chip Used To Make Crystal Radio

June 1, 2020 by Zoe Skyforest 23 Comments

Perhaps the simplest radio one can build is the crystal radio. Using a diode as a detector, the design generally uses less than 10 components and no battery, getting its power to run from the radio signal itself. [Billy Cheung] decided to build a crystal radio using a rather unconventional detector – the smart chip in a common credit card.

This is possible because the smart chip on many credit cards contains a diode. It’s then a simple matter of hooking up the right pads on the credit card to the rest of a crystal radio circuit, and you’re all set. Of course, [Billy] goes the whole hog, building the entire radio on a single credit card. Other cards are cut up to create bobbins for winding coils to form a variable inductor, used to tune the radio. Doing this allows for a much cleaner, thinner design, rather than using a variable capacitor which is comparatively hard to find. Turning the dial allows stations to be tuned in, and with a high impedance earbud hooked up, you’re listening to AM radio. Oh, and don’t forget an antenna!

[Billy] breaks down the details for anyone wishing to replicate the feat, going so far as to wind the coils in real time in his Youtube video. Cutting templates and other details are available on Github. While it’s not going to be the most replicated hack, as it requires the destruction of a credit card to achieve, we love the ingenuity. And, if society does collapse, we’ll all have a great source of diodes when the ATMs have all become useless. Video after the break.

[Thanks to Zane Atkins for the tip!]

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Easy Internet For Retro Computers With The PiModem

June 1, 2020 by Zoe Skyforest 34 Comments

Retro computers are great, but what really makes a computer special is how many other computers it can talk to. It’s all about the network! Often, getting these vintage rigs online requires a significant investment in dusty old network cards from eBay and hunting down long-corrupted driver discs to lace everything together. A more modern alternative is to use something like PiModem to do the job instead.

PiModem consists of using a Raspberry Pi Zero W to emulate a serial modem, providing older systems with a link to the outside world. This involves setting up the Pi to use its hardware serial port to communicate with the computer in question. A level shifter is usually required, as well as a small hack to enable hardware flow control where necessary. It’s then a simple matter of using tcpser and pppd so you can talk to telnet BBSs and the wider Internet at large.

It’s a tidy hack that makes getting an old machine online much cheaper and easier than using hardware of the era. We’ve seen similar work before, too!

Build Your Own Dial-Up ISP – Now With Modem Pool!

May 30, 2020 by Zoe Skyforest 54 Comments

When it was the only viable option, the screech and squeal of dial-up internet was an unwelcome headache to many. But now that its time has passed, it’s gained a certain nostalgia that endears it to the technophiles of today. [Doge Microsystems] is just one such person, who has gone all out to develop their very own dial-up ISP for multiple clients.

The retro network is based on an earlier single-device experiment, with a Raspberry Pi 3B acting as the dial-up server. It’s hooked up to four modems, three of which are connected over USB-serial adapters implementing hardware flow control.

Obviously, four analog phone lines are hard to come by in this day and age, so [Doge] uses Asterisk along with a series of Linksys SIP devices to create their own PBX network. Each modem gets a phone line, with four left over for clients to dial in.

To connect, users can either call a certain modem directly, or dial a special number which rings the whole pool. Thanks to mgetty, each modem is set up to answer on a different number of rings to allow the load to be shared. Once connected, a PPP daemon handles connecting the user to the Internet at large.

While it’s unlikely we’ll all be ringing [Doge]’s house to get our next YouTube fix, owning your own dial-up ISP is certainly an admirable feat. We’d love to see it deployed in the field sometime, perhaps at a hacker conference or Burning Man-type event. Of course, if you’ve got your own old-school network pumping data, be sure to let us know! Video after the break.

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Cheap Speakers Sound Good With Easy Open Baffle Design

May 29, 2020 by Zoe Skyforest 20 Comments

If you’ve spent any time around audio gear at all, you’ll know that enclosure design is as critical as the speaker drivers themselves. [Frank Olson] demonstrates this ably, with his open baffle design for some cheap off-the-shelf speakers.

[Frank]’s aim was to do a comparison between using no enclosure, and an open baffle design, with a pair of 2″ full-range speakers. These drivers are nothing special; just a low-cost part that you’d find in any cheap set of computer speakers. [Frank] screws the drivers into a thin, flat wooden board, and then adds a supporting strut to allow the speakers to stand on their own.

The comparison makes it clear that even this basic baffle design makes a big difference to perceived sound quality. Bass is fuller, and the sound is far improved thanks to the baffle blocking out of phase sounds from the rear of the speaker.

It’s a technique that could prove useful to anyone quickly trying to rig up an audio setup for the workshop or makerspace out of leftover parts. We’ve featured similar projects before that espouse the benefit of enclosure design when using even very affordable speakers. Video after the break.

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Dim Hallway Gets Lighting Upgrade

May 27, 2020 by Zoe Skyforest 13 Comments

There’s nothing worse than a lightswitch that’s nowhere near where it should be, leaving you fumbling around in the dark. [supersquirrel72] had just this problem, and decided to put an Arduino to work instead.

Rather than using the original mains lighting that was poorly positioned and not enough to light the hall, instead 2 meters of white LED strip was chosen. The form factor is perfect for lighting a long, thin space – far better than running a series of seperate bulbs. The strip was rigged up to an Arduino Uno, that triggers the lights when movement is detected with a simple PIR motion sensor. After some feedback from the other occupants of the house, it was decided to tweak things further. An RTC was implemented to allow the Arduino to keep things dimmer after 9PM, so as to not wake others when making a trip to the kitchen for a midnight snack.

It’s a simple solution which brightens up the hallway nicely. We imagine this could just be the first step to a yet-more-integrated lighting solution in [supersquirrel72]’s house. Whether it’s IOT lights or something more festive, we can’t wait to see what’s next.

Building A Serious Solar Inverter Battery Pack

May 27, 2020 by Zoe Skyforest 35 Comments

If you’re out in the wilderness, having plenty of electricity on hand is a blessing. Eschewing fossil fuels, [LithiumSolar] is, as their name suggests, a fan of other technologies – undertaking the construction of a 3.5kWh solar generator that’s rugged and ready for the outdoors.

The build starts with 18650 lithium-ion cells sourced from a recycler, packed inside obsolete modem battery packs. After harvesting 390 cells, the best 364 are chosen and assembled into plastic holders to create a 14S26P configuration. A spot welder is employed to weld the pack together, with XT60 connectors used as the main bus connectors, albeit in a very non-standard configuration. Balance leads are hooked up to a 14S battery management system, to keep things in check. The huge pack is then installed inside a stout Craftsman toolbox, along with a MPPT solar charger module, and a 1500W inverter for output.

The build video is a great resource for anyone interested in building custom 18650 packs or battery solar power systems. [LithiumSolar] does a great job of clearly explaining each step and the reasons for part selections along the way. Of course, in a neat dovetail to this project, we’ve even seen solar-powered spot welders before – which would be useful if you need to replicate this build out in the field somewhere. Video after the break.

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