Bolstering Raspberry Pi HDMI with a current regulator

rpi-hdmi-current-regulator

We’ve never tried using an HDMI to VGA converter with Raspberry Pi. We heard they were expensive and have always just used HDMI out (although DVI would be just as easy). Apparently if you have a VGA converter that isn’t powered the RPi board may output unstable video due to lack of current from the connector. [Orlando Cosimo] shows how to fix the problem with a few inexpensive components.

Just this morning we saw a portable PSU using an LM317. This project uses the same part, but in a different way. [Orlando] uses three resistors in parallel to make the LM317 behave like a current regulator (as opposed to a voltage regulator) which will output about 550 milliamps. Input voltage is pulled directly from the 5V line of the microUSB port. The output is injected into the HDMI connector. This will boost the amount of juice available to the unpowered VGA converter, stabilizing the system.

There are a lot of other power hacks out there for the RPi. One of our favorites is pulling the stock linear regulator in favor of a switch mode regulator.

[via Dangerous Prototypes]

Hackaday Links: Sunday, June 30th, 2013

hackaday-links-chain

The race is on to squeeze cycles out of an 8MHz AVR chip in order to better drive the WS2811 LED protocol.

[Asher] doesn’t want to buy charcoal aquarium filters if he can just build them himself. He filled a couple of plastic drink bottles with charcoal, cut slots in the sides, and hooked them up to his pump system. A gallery of his work is available after the break.

Is the best way to make microscopic sized batteries to 3d print them? Harvard researchers think so. [Thanks Jonathan and Itay]

The Ouya gaming console is now available for the general public. [Hunter Davis] reports that the Retrode works with Ouya out-of-the-box. If you don’t remember hearing about it, Retrode reads your original cartridge ROMs for use with emulators.

Making a cluster computer out of 300 Raspberry Pi boards sounds like a nightmare. Organization is the key to this project.

Hackaday alum [Jeremy Cook] is working on an animatronic cigar box. Here he’s demonstrating it’s ability to listen for voice commands.

A Kelvin clips is a type of crocodile clip that has the two jaws insulated from each other. [Kaushlesh] came up with a way to turn them into tweezer probes.

[Read more...]

RF wireless kernel module for Raspberry Pi, BeagleBone and others

rfm12b-kernel-module

If you’ve done any wireless work with hobby electronics you probably recognize this part. The green PCB is an RFM12B wireless board. They come in a few different operating bandwidths, the 433 MHz is probably the most common. They’re super easy to interface with a small microcontroller but what about an embedded Linux board? That is the focus of this project, which builds a kernel driver for the RF module.

You can get your own RFM12B for a few bucks. They’re quite versatile when paired, but a lot of inexpensive wireless consumer goods operate on this band so the board can be used to send commands to wireless outlets, light fixtures, etc. [Georg] has been working with the BeagleBone, BeagleBone Black, and Raspberry Pi. His software package lets you build a kernel module to add an entry for the device into the /dev directory of a Linux system. So far the three boards listed are all that’s supported, but if you have five I/O pins available it should be a snap to tailor this to other hardware.

Wondering what else you can do with the setup? This will get the receiving end of a text-messaging doorbell up and running in no time.

[Read more...]

Atari 2600 has a Raspberry Pi hiding under the hood

raspberry-pi-2600

Seriously, the drawer pull on this Atari 2600 is not stock. Don’t they know this voids the warranty? The thing is, you won’t actually find any of the original internals anyway. When building this portable emulator housed in a 2600 case [Linear Nova] was careful to ensure that everything could be restored to its original condition (except for two hinges mounted on the back) sometime down the road. That’s a good goal to set for yourself. We think the build is the fun part of most projects and often wonder what to do with them when they’re done and our interest has waned.

A seven-inch LCD screen was attached to the underside of the lid using Velcro. When tilted up it’s at a nice viewing angle for the player. [Linear] prefers to use a Wii remote as the control this portable video game emulator. It connects to the Raspberry Pi over Bluetooth using a USB dongle. The advantage of this is that you just throw the remote inside the case too. For now there are two power cords, one for the RPi and the other for the LCD screen but he plans to add a power hub in the future to narrow this down to one. We wonder it that would also be a good time to add his own rechargeable battery pack option? There should be enough room for an RC style pack.

 

 

Pager message sniffing with RPi and SDR

rpi-pager-message-sniffing

The 1990’s called, they want you to use modern technology to listen in on your friends’ pager messages. Seriously, how many people are still using pagers these days? We guess you can find out by building your own Software-Define Radio pager message decoder.

[Sonny_Jim] bought an RTL2832 based USB dongle to listen in on ADS-B airplane communications only to find out the hardware wasn’t capable of communicating in that bandwidth range. So he set out to find a project the hardware was suited for and ended up exploring the POCSAG protocol used by paging devices. It turns out it’s not just used for person-to-person communications. There are still many automated systems that use the technology.

Setting things up is not all that hard. Reading the comments on the project log show some folks are having dependency issues, but these sound rather banal and will be a good chance for you to brush up on your Linux-fu. Once all the packages are installed you’re simply working with text which can be displayed in a myriad of ways. [Sonny] set up a text files on the Pi’s webserver so that he can check out the latest captures from a smartphone.

[Image Source]

Raspberry Pi replaces a Volvo nav system

rpi-replaces-volvo-nav

[Reinis] has a Volvo S80. One of the dashboard features it includes is a 6.5″ LCD screen which periscopes up to use as a navigation system. The problem is that Volvo stopped making maps for it around five years ago and there are no maps at all for Latvia where he lives. So it’s worthless… to you’re average driver. But [Reinis] is fixing it on his own by replacing the system with a Raspberry Pi.

That link leads to his project overview page. But he’s already posted follow-ups on hardware design and initial testing. He’s basing the design around a Raspberry Pi board, but that doesn’t have all the hardware it needs to communicate with the car’s systems. For this he designed his own shield that uses an ATmega328 along with a CAN controller and CAN transceiver. The latter two chips patch into the CAN bus on the car’s On Board Diagnostic system. We didn’t see much about the wiring, but the overview post mentions that the screen takes RGB or Composite inputs so he must be running a composite video cable from the trunk to the dashboard.

 

Raspberry Pi Tor proxy lets you take anonymity with you

pi-tor-proxy

Your web traffic is being logged at many different levels. There are a few different options to re-implement your privacy (living off the grid excluded), and the Tor network has long been one of the best options. But what about when you’re away from you home setup? Adafruit has your back. They’ve posted a guide which will turn a Raspberry Pi into a portable Tor proxy.

The technique requires an Ethernet connection, but these are usually pretty easy to come by in hotels or relatives’ homes. A bit of work configuring the Linux network components will turn the RPi into a WiFi access point. Connect to it with your laptop or smartphone and you can browse like normal. The RPi will anonymize the IP address for all web traffic.

Leveraging the Tor network for privacy isn’t a new subject for us. We’ve looked at tor acks that go all the way back to the beginnings of Hackaday. The subject comes and goes but the hardware for it just keeps getting better!

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