A Star Tracking Telescope Mount

[Chris] recently got his hands on an old telescope. While this small refractor with an altitude-azimuth mount is sufficient for taking a gander at big objects in our solar system, high-end telescopes can be so much cooler. Large reflecting telescopes can track the night sky for hours, and usually come with a computer interface and a GOTO button. Combine this with Stellarium, the open source sky map, and you can have an entire observatory in your back yard.

For [Chris]’ entry into the 2016 Hackaday Prize, he’s giving his old telescope an upgrade. With a Raspberry Pi, a few 3D printed adapters, and a new telescope mount to create a homebrew telescope computer.

The alt-az mount really isn’t the right tool for the astronomical job. The earth spins on a tilted axis, and if you want to hold things in the night sky still, it has to turn in two axes. An equatorial mount is much more compatible with the celestial sphere. Right now, [Chris] is looking into a German equatorial mount, a telescope that is able to track an individual star through the night sky using only a clock drive motor.

To give this telescope a brain, he’ll be using a Raspberry Pi, GPS, magnetometer, and ostensibly a real-time clock to make sure the build knows where the stars are. After that, it’s a simple matter of pointing the telescope via computer and using a Raspberry Pi camera to peer into the heavens with a very, very small image sensor.

While anyone with three or four hundred dollars could simply buy a telescope with similar features, that’s really not the point for [Chris], or for amateur astronomy. There is a long, long history of amateur astronomers building their own mirrors, lenses, and mounts. [Chris] is just continuing this very long tradition, and in the process building a great entry for the 2016 Hackaday Prize

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Arduino Comes To The Raspberry Pi, Linux ARM Devices

Arduino is the perfect introduction to microcontrollers and electronics. The recent trend of powerful, cheap, ARM-based single board Linux computers is the perfect introduction to computer science, programming, and general Linux wizardry. Until now, though, Arduino and these tiny ARM computers have been in two different worlds. Now, finally, there are nightly builds of Arduino IDE on the Raspberry Pi and other single board Linux computers.

The latest Arduino build for ARM Linux popped up on the arduino.cc downloads page early this week. This is the result of an incredible amount of work from dozens of open source developers across the Arduino project. Now, with just a simple download and typing ‘install’ into a terminal, the Arduino IDE is available on just about every single board Linux computer without having to build the IDE from source. Of course, Arduino has been available on the Raspberry Pi for a very long time with sudo apt-get install arduino, but this was an older version that cannot work with newer Arduino boards.

Is this distribution of the Arduino IDE the same you would find on OS X and Windows? Yep, everything is the same:

While this is really just arduino.cc improving their automated build process and putting a link up on their downloads page, it does make it exceptionally easy for anyone to set up a high school electronics lab. The Raspberry Pi is almost a disposable computing device, and combining it with Arduino makes for a great portable electronics lab.

Gameboy Case Lives On With A Pi Zero

After scoring a non-functioning Gameboy in mint condition for $10, [Chad] decided it was time for a fun electronics project, so he ordered an LCD and bought a Pi Zero.

He started with a 3.5″ LCD off eBay for about $25, and got it running with the Pi Zero. It’s only 320×240 resolution, but hey, we’re recreating a Gameboy — not a smartphone. The next step was rather finicky: cutting up the case to fit the new components in.

Using a collection of files he whittled down the screen opening in the case to make room for the LCD, a few hours later and it looked surprisingly good.

From there he started laying out the components inside of the case, trying to figure out the best layout for everything to fit nicely. To power the unit he’s using a lithium ion battery from a Samsung Note which should give him some serious play-time. It fits right in where the game card is suppose to go.

To add some extra control functionality he’s added the game-pad buttons from a SNES onto the back where the battery door is, he’s also got a USB port on the side, a MicroSD card slot, and even a new audio pre-amp with potentiometer for controlling the speaker volume.

In case you can’t find a mint condition Gameboy case like [Chad] did, you could just print one from scratch

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Why Buy Your Children A Game Console When You Can Build Them One?

[buildxyz] had no opposition to his kids playing video games, but wanted something that offered a bit more parental control, a larger game selection, and was maybe a little more contained than a modern game console.

So, in his multi-part build log, he goes through all the steps of making a Raspberry Pi into a kid friendly wall-mounted game console. The frame is made from Baltic Birch plywood, and the edges look cool when stained. The display is an old HP monitor, and the speakers are simple beige bricks from the thrift store. The controllers hook into a USB hub on the front. It’s not a complicated build, but it’s very well done.

The coolest feature, from the parent’s point of view, is the combination lock on the front. A rotary encoder surrounded by NeoPixels provides the input and feedback. Depending on the code [buildxyz] inputs his children can receive different periods of dopamine hits, and if he enters a special code for occasions like birthdays, unlimited play time becomes available.

We hope he’s prepared to have the only four year olds who can crack safes on the block. The build looks awesome, and there’s not really a commercial product out there to match it. Watch the video.

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Make Your Mailman Nervous With A Wifi Enabled Mailbox

“It’s not a bomb,” the mailman whispered to himself as he reached for [atxguitarist]’s mailbox, giving a nervous glance at the small black box stuck to the side. “This is THAT house, it’s not a bomb. I’m sure it’s not a bomb,” he muttered as a cold bead of sweat ran down his neck. His hand approached slowly, shakily. The mailman gathered courage, then, in a single quick movement, opened the box. He sighed relief as nothing happened. Somewhere in [atxguitarist]’s house a recording wailed “You’ve got mail!”

The mailbox enhancement in question is a hacked Amazon Dash Button in a project box. When the door of the mailbox is opened, a magnetic reed switch simulates a button press on the Dash. The Dash transmodulates the signal into WiFi pixies which are received by a Raspberry Pi. The Pi’s sole purpose in life is to run a 24-line Python script that plays the famous sound from AOL’s mail software and sends a notification to his phone.

Aside from unnerving the mailman, it’s a cool hack and keeps you from slugging it out there in the cold or rain to witness an empty box.

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DVB-S From A Raspberry Pi With No Extra Hardware

An exciting aspect of the trend in single board computers towards ever faster processors has been the clever use of their digital I/O with DSP software to synthesize complex signals in the analogue and RF domains that would previously have required specialist hardware. When we use a Raspberry Pi to poll a sensor or flash an LED it’s easy to forget just how much raw processing power we have at our fingertips.

One of the more recent seemingly impossible feats of signal synthesis on a Raspberry Pi comes from [Evariste Courjaud, F5OEO]. He’s created a DVB-S digital TV transmitter that produces a usable output direct from a GPIO pin, with none of the external modulators that were a feature of previous efforts required. (It is worth pointing out though that for legal transmission a filter would be necessary.)

DVB is a collection of digital TV standards used in most of the world except China and the Americas. DVB-S is the satellite version of DVB, and differs from its terrestrial counterpart in the modulation scheme it employs. [Evariste] is using it because it has found favor as a digital mode in amateur radio.

This isn’t the first piece of [F5OEO] software creating useful radio modes from a GPIO pin. He’s also generated SSB, AM, and SSTV from his Pi, something which a lot of us in the amateur radio community have found very useful indeed.

We’ve covered digital TV creation quite a few times in the past on these pages, from the first achievement using a PC VGA card almost a decade ago to more recent Raspberry Pi transmitters using a USB dongle and a home-built modulator on the GPIO pins. Clever signal trickery from digital I/O doesn’t stop there though, we recently featured an astoundingly clever wired Ethernet hack on an ESP8266, and we’ve seen several VHF NTSC transmitters on platforms ranging from the ESP to even an ATtiny85.

Thanks [SopaXorzTaker] for the nudge to finally feature this one.

Raspberry Pi As Speed Camera

Wherever you stand on the topics of road safety and vehicle speed limits it’s probably fair to say that speed cameras are not a universally popular sight on our roads. If you want a heated argument in the pub, throw that one into the mix.

But what if you live in a suburban street used as a so-called “rat run” through route, with drivers regularly flouting the speed limit by a significant margin. Suddenly the issue becomes one of personal safety, and all those arguments from the pub mean very little.

Sample car speed measurements
Sample car speed measurements

[Gregtinkers]’ brother-in-law posted a message on Facebook outlining just that problem, and sadly the local police department lacked the resources to enforce the limit. This set [Gregtinkers] on a path to document the scale of the problem and lend justification to police action, which led him to use OpenCV and the Raspberry Pi camera to make his own speed camera.

The theory of operation is straightforward, the software tracks moving objects along the road in the camera’s field of view, times their traversal, and calculates the resulting speed. The area of the image containing the road is defined by a bounding box, to stop spurious readings from birds or neighbours straying into view.

He provides installation and dependency instructions and a run-down of the software’s operation in his blog post, and the software itself is available on his GitHub account.

We’ve had a lot of OpenCV-based projects but haven’t featured a speed camera before here on Hackaday. But we have had a couple of dubious countermeasures, like that humorous attempt at an SQL injection attack, or a flash-based countermeasure.