Building a Barn Door tracker for astronomical photography

That’s a pretty amazing image to catch peering out from your back balcony. The rig used to record such a gem is seen on the right. It’s called a Barn Door tracker and was built by [DCH972]. Details for this build are scattered all over the place, there’s a video (also found below), another album of some of the best images, and plenty of background info in the Reddit thread.

This design is also know as a Haig or Scotch mount. While we’re dropping links all over the place check out the Wikipedia page on the topic. The point of the system is to move the camera in such a way so that the stars appear to hold in the same place even though the earth is moving. There’s an ATmega32u4 breakout board riding on top of the breadboard. It’s doing some pretty heavy math in order to calculate the stepper motor timing. That’s because the mount is like a photo album, hinged at one side and opened on the other by a ball screw. This linear actuation needs to be meshed with the change in angle of the mounting platform, and finally it needs to sync with the movement of the earth. But once a series of images is captured correctly they can be processed into the composite photograph shown above.

If missed that SDR galactic rotation detector from last May you should find it equally compelling.

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Brute force attack Xbox 360 parental controls

brute-force-xbox-360-parental-controls

The Xbox 360 has the option of parental controls. It limits the rating of games which can be played on the system. [Oscar] didn’t really need to remove the lock-out. It was simply an interesting proof of concept for him. In the image above he’s holding up a Vinciduino board. It has an ATmega32u4 chip that can brute-force attack the Xbox 360 parental code (translated).

We’ve seen quite a few of these attacks lately. Like the recent iPad pin attack this uses the microcontroller to emulate a keyboard. As you can see in the video, [Oscar] first navigates the menu system to the unlock code screen, then plugs in his device.

The unlock screen calls for a four-digit numeric PIN. That’s a total of 10000 possible combinations. It looks pretty slow in the demo, but according to his calculations the worst case scenario would still break the code in less than seventeen hours. Apparently there’s no lock-out for the max number of wrong codes.

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Ditch that boring mouse for a military-grade trackball

military-grade-trackball

The bad thing about this type of hack is that now [Tomek Dubrownik] needs to cut a hole in his desk to house the thing. He got this military grade trackball working over USB. It’s old, and could be used as a blunt weapon. But as the video shows it still makes a great input device.

He found the hardware on Allegro — a Polish auction site similar to eBay — for just $20. The original circuitry didn’t make a lot of sense, but a bit of probing with the old oscilloscope let him establish connections to the encoders which are read by some TI 54xx parts. Apparently they use the same logic as 7400 parts but are military grade. He chose a ATmega32u4 development board for his replacement control board. That chip has native USB support so the rest is just a matter of passing data like an HID input device. His code even lets him use those pushbuttons to toggle between cursor movement and window scrolling.

[Tomek] translated his post into English after some prompting by friends at the Warsaw Hackerspace. Here’s the original in Polish if you’re interested.

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AVR programmer made without a programmer

[blueHash] uses this cheap development board as an AVR programmer. What’s interesting to us is that it solves the chicken-or-egg problem that is usually encountered when bootstrapping a programmer. We’ve written about this issue before. Most programmers use microcontrollers, which first need to be flashed using a programmer. But it turns out the chip on this dev board has a DFU mode which gets around that conundrum.

He grabbed a uSD dev board for about $6. It’s got a crystal, an ATmega32u4 chip, and on the other side there’s a MicroSD card slot. We looked around and found an Atmel Datasheet (PDF) which describes the Device Firmware Upgrade mechanism. The AVR devices which support DFU are factory configured to use it. This dev board is designed to use DFU so all [blueHash] needed to do is find and configure a ISP firmware package that worked with this chip.

GPS dog collar keeps track of your walks

[Becky Stern] came up with a way to make sure you and your dog are getting enough exercise. It’s a dog collar mounted GPS that measures how far you have walked. Just set your target distance and the progress bar in the middle of this flower will let you know when you reached it.

The most obvious piece of hardware is the OLED board which is sticking out like a sore thumb. But if you’d like to be a little more discreet you could forego the full-featured display for some carefully places LEDs to make up a circular progress bar. The GPS module itself fits well in the center of the flower, which [Becky] shows us how to make out of wire-edged ribbon. Hidden on the other side is an ATmega23u4 breakout board running the Arduino bootloader.

If you’re interested in sewables and textiles [Becky] uses a lot of basic techniques that are good to learn. Check it out in the clip after the break. She’s always shown a remarkable ability to develop projects which won’t scare away the villagers in the way our wire-sprouting breadboard hacks sometimes do.

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Drop-in board for NES ROM chip makes cartridge reprogrammable

Here’s the guts from [Dext0rb’s] Super Nintendo cartridge. It’s easy to pick out the dark-colored board which lets him reflash SNES ROMs via USB. We’ve seen this done a number of times, but this is a much cleaner option than hacks that just add a dead-bug-style memory chip.

The board he designed has a double-row of pin headers sized to fit the footprint vacated by the original ROM chip. The board has a mini-USB connector which can be accessed through a hole he cut in the side of the cartridge enclosure. This is in the right place so that you cannot plug it in when it’s being used in the SNES (which would cause damage). The ATmega32u4 chip handles USB connectivity and programs the 32 megabit flash chip which stores the ROM. He’s posted a few articles on the blog portion of his site which you’ll find interesting. We suggest starting with this hardware teaser.

A very detailed reflow oven build

smd-solder-reflow-oven

If you do a lot of SMD soldering, a reflow oven is the fastest and most efficient way to get all those tiny components attached to your PCB. [Frank Zhao] saw the reflow ovens we featured here over the last few weeks and figured he might as well show off his rig as well. We’re certainly glad he did, because his very thorough writeup is a great stepping stone for anyone looking to construct a reflow oven of their own.

Like many others, he started off with a used toaster oven, modifying it to be controlled directly via the power cable rather than the oven’s dials. He built a small PCB to regulate the oven, which features an ATmega32u4 and thermocouple to keep the temperature in check. Control of the heating element is done using a solid state relay, for which he built his own heatsink.

He studied the reflow profile of the solder he would be using, programming the microcontroller to regulate the heating/cooling process without requiring any user input, aside from turning the oven on.

Check out the video below to see a brief overview of his system, and be sure to swing by his writeup to take a look at all the build details. There are a handful of additional videos along with plenty of pictures there, walking through each step of the process.

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