Raspberry Pi

1836 Articles

RasPi Traffic Monitor

Dedicated Automobile Traffic Monitor With Raspberry Pi

January 6, 2015 by 31 Comments

[j3tstream] wanted an easier way to monitor traffic on the roads in his area. Specifically, he wanted to monitor the roads from his car while driving. That meant it needed to be easy to use, and not too distracting.

[j3tstream] figured he could use a Raspberry Pi to run the system. This would make things easy since he’d have a full Linux system at his disposal. The Pi is relatively low power, so it’s run from a car cigarette lighter adapter. [j3tstream] did have to add a custom power button to the Pi. This allows the system to boot up and shut down gracefully, preventing system files from being corrupted.

After searching eBay, [j3tstream] found an inexpensive 3.2″ TFT LCD touchscreen display that would work nicely for displaying the traffic data. The display was easy to get working with the Pi. [j3tstream] used the Raspbian linux distribution. His project page includes a link to download a Raspbian image that already includes the necessary modules to work with the LCD screen. Once the image is loaded, all that needs to be done is to calibrate the screen using built-in operating system functions.

The system still needed a data connection. To make things simple and inexpensive, [j3tstream] used a USB WiFi dongle. The Pi then connects to a WiFi hot spot built into his 4G mobile phone. To view the traffic map, [j3tstream] just connects to a website that displays traffic for his area.

The last steps were to automate as much as possible. After all, you don’t want to be fumbling with a little touch screen while driving. [j3tstream] made some edits to the LXDE autostart file. These changes automatically load a browser in full screen mode to the traffic website. Now when [j3tstream] boots up his Pi, it automatically connects to his WiFi hotspot and loads up local traffic maps.

The Smallest Portable Pi

January 3, 2015 by 17 Comments

What do you get when you take an extremely small Raspberry Pi clone and stuff it inside a Game Boy Advance SP? We don’t know what to call it, but it’s probably one of the best portable gaming machines ever made, able to run emulators ranging from the Apple II to playing Quake III natively on a tiny flip-top display.

This isn’t the first time we’ve seen [frostedfires]’ work on a tiny system stuffed into a Game Boy. The initial post on this build over on the bacman forums just covered the basics – getting an Odroid W up and running, and putting Quake III on the tiny display. Now that the build is complete, we can get a look at what it takes to turn a Raspberry Pi clone into one of the smallest portable projects we’ve ever seen.

Using a Raspi clone as the only component in a tiny portable emulation station isn’t possible, so [frostefires] added a few other bits of electronics to make everything work. There’s a joystick from a PSP in there to work as the mouse, a few extra buttons in addition to the stock Game Boy ones, A USB hub, WiFi adapter, speaker and amplifier, a battery and the related charging electronics, and a Teensy 3.1 to handle all the input.

It’s a very impressive build that can run emulators ranging from the Apple II to later generation Nintendo consoles and handhelds (including the Game Boy Advance), but since the HDMI connector is availble on the outside of the case, [frostedfires] can also use this as a tiny, portable media center. Check out the video below to see this Game Boy in action, playing Mario Kart and 1080p video.

Continue reading “The Smallest Portable Pi” →

Multiplexing Pi Cameras

December 19, 2014 by 39 Comments

The Raspberry Pi and its cool camera add-on is a great way to send images and video up to the Intertubes, but what if you want to monitor more than one scene? The IVPort can multiplex up to sixteen of these Raspi camera modules, giving the Pi sixteen different views on the world and a ridiculously high stack of boards connected to the GPIO header.

The Raspberry Pi’s CSI interface uses high-speed data lines from the camera to the CPU to get a lot of image data quickly. Controlling the camera, on the other hand, uses regular old GPIOs, the same kind that are broken out on the header. We’ve seen builds that reuse these GPIOs to blink a LED, but with a breakout board with additional camera connectors, it’s possible to use normal GPIO lines in place of the camera port GPIOs.

The result is a stackable extension board that splits the camera port in twain, allowing four Raspi cameras to be connected. Stack another board on top and you can add four more cameras. A total of four of these boards can be stacked together, multiplexing sixteen Raspberry Pi cameras.

As far as the obvious, ‘why’ question goes, there are a few interesting things you can do with a dozen or so computer controlled cameras. The obvious choice would be a bullet time camera rig, something this board should be capable of, given its time to switch between channels is only 50ns. Videos below.

Continue reading “Multiplexing Pi Cameras” →

Meme Themed Pinball Machine – Much Flipping, Y U No Win?!

December 18, 2014 by 10 Comments

Summoning 4chans, 9gags, Reddits and other denizens of easily-digested content, Liberty Games stripped apart a dilapidated “Baby Doll” pinball arcade machine and turned it into this meme-spouting monstrosity. A complete redo of the vinyl and graphics to sport dozens of familiar internet tropes was first, then they had Shapeways create internal scenery and finally some electronics were added to spice things up.

We have seen PINMAME-based digital machines but this took a different path. Pinball machines this old pre-date common transistors so they rely on electro-mechanicals for everything. This made hacking the machine challenging so the team intercepted most of the signals and tied them into a Raspberry Pi with a Pi-face interface board. A videoscreen was added to the scoreboard, triggering all manner of memey videos and sounds according to actions performed and unlocked on the screen.

If you yearn for expired pranks of years gone by and are bad at pinball, you are in luck. Losing the game gets you Rickrolled – over and over again. On the plus side, Nyan Cat rockets away to bonuses and even the Admiral himself warns you of impending danger.

We resisted the urge to write this article as a chain of one meme to the next, you will get plenty of that from the well-documented project conversion and the following video. Someone in the comments will probably make a list of all memes.

Continue reading “Meme Themed Pinball Machine – Much Flipping, Y U No Win?!” →

Create An Inclinometer Using A Raspberry Pi

December 16, 2014 by 11 Comments

The latest gizmo that you can make using the cheap and easy Raspberry Pi is here courtesy of [Mark Williams]. He has hooked up an inertial measurement unit (IMU) to the Pi and built an inclinometer to use to measure the various angles of an off-road vehicle.

This particular guide goes through the setup of SDL to control the video output to a small screen. Then, a function is created to rotate the images based on input from the IMU so that the vehicle position can be shown graphically on the screen. Now, when your truck is about to roll over on a hill, you’ll get advance warning!

Of course, this whole project is predicated on installing the IMU and getting it up and running on the Raspberry Pi in the first place. [Mark] has you covered on a guide for setting that up as well. This delves into setting up the IMU over I2C to get it talking to the Raspberry Pi, and then converting the raw data from the IMU into data that is more usable. Be sure to check out [Mark]’s page for all of the code and details!

Redlining Your CPU Via Automotive Tachometer

December 14, 2014 by 15 Comments

Many CPU-usage widgets have stylistically borrowed from vehicles, displaying something mimicking the tachometer found in the dashboard. [Pat] took it a step further and tried his hand at re-borrowing this style. He figured, why not use an actual physical tachometer to display how hard the CPU on his Raspberry Pi was revving?

With the goal of tuning 0-100% CPU usage to 0-8000 RPM on the tach, the first step was diagnosing the range of PWM input frequencies that moved the needle across the tach’s full arc. Using his Tektronix 3252C function generator he quickly determined 0-440 Hz would be needed and graphed a handful of intermediate points. The response curve was not linear, so he drew up some fudging guidelines to make all the datapoints match.

Next, he wrote a few lines of Python (he shared) to make the Pi to poll its CPU usage and translate it to the proper frequency. The Pi makes outputting easy, GPIO pin 11 carried the signal to a 7404 for buffering, then out to the tach. The automotive tach itself ran on 12V, but its input signal required only 5V so he pulled a 7805 from his parts bin.

Once it was all put together it worked beautifully using just the one extra component. Some might see this as more clever than USB dependent or Arduino bloated based tachometer hacks.

See the video after the break of the tach twitching even when the mouse moved, and pegging the red when opening a browser. No more need to use up valuable screen real-estate (or use a screen at all) if you want to see at a glance when your Pi is putting in work.

Continue reading “Redlining Your CPU Via Automotive Tachometer” →

1.37″ CRT Restored By Hacklab For Miniature MAME Cabinet

December 13, 2014 by 27 Comments

For $5, [William] of Toronto’s Hacklab hackerspace got a hold of one of the smallest CRT screens ever made – about the size of a large coin. Over the course of a couple sessions – including a public hack boothside at their Mini Makerfaire – [William], [Igor], and several other members managed to connect it as a monitor directly off a Raspberry Pi. The end-goal is the world’s smallest MAME cabinet (smaller by almost half than this LCD one).

As Canada followed the US and stopped broadcasting analog back in 2011, it became quite a challenge to feed the screen a video source. They disclosed early that the easiest solution would just be an RF transmitter on the Pi and then tune the micro-set to that channel. Too easy. They wanted something elegant and challenging so they went digging into the circuitry to find a place to insert a composite video signal directly.

The real story here is their persistence at reverse engineering. The PCB was folded like a cardboard box to fit in the original case, making large portions of the circuitboard and wiring inaccessible. Even when they managed to trace the signal to what they thought was the appropriate chip (marked C80580), they could not find any information on the 30 year old chip. Noting that every other chip on the board was Panasonic and started with “AN5”, [Igor] suspected the mystery silicon was just renamed and went through every single datasheet he could find with that prefix. Combined with form factor, pin count and purpose, his sleuthing was rewarded with a guess for a match – the AN5715. His hunch was correct – using that datasheet led him to the answers they required.

Then they just had to figure out how get the composite signal the Pi outputted into something the chip would use to display the correct image. There were no shortage of challenges, failures and dead ends here either, but they had help from the rest of their membership.

Their project log is an interesting narrative through the process and in the end of course, it worked. It is displayed beautifully with a clear acrylic case and ready for a cabinet to be built.