Schematic for a boost converter based on the ATtiny MCU

An ATtiny Boost Converter

December 7, 2014 by 49 Comments

This schematic is all you need to build your own voltage converter. [Lutz] needed a converter that could boost 5 V to 30 V to power a string of LEDs. The solution was to use low cost ATtiny85 and some passive components to implement a boost converter.

This circuit follows the classic boost converter topology, using the ATtiny85 to control the switch. The 10 ohm resistor is fed back into the microcontroller’s ADC input, allowing it to sense the output voltage. By measuring the output voltage and adjusting the duty cycle accordingly, the circuit can regulate to a specified voltage setpoint.

A potentiometer is used to change the brightness of the LEDs. The software reads the potentiometer’s output voltage and adjusts the voltage output of the circuit accordingly. Higher voltages result in brighter LEDs.

Of course, there’s many other ways to implement a boost converter. Most practical designs will use a chip designed for this specific purpose. However, if you’re interested in rolling your own, the source and LTSpice simulation files are available.

amazonfiretv

Amazon Fire TV Update Bricks Hacked Devices

December 7, 2014 by 60 Comments

The Amazon Fire TV is Amazon’s answer to all of the other streaming media devices on the market today. Amazon is reportedly selling these devices at cost, making very little off of the hardware sales. Instead, they are relying on the fact that most users will rent or purchase digital content on these boxes, and they can make more money in the long run this way. In fact, the device does not allow users to download content directly from the Google Play store, or even play media via USB disk. This makes it more likely that you will purchase content though Amazon’s own channels.

We’re hackers. We like to make things do what they were never intended to do. We like to add functionality. We want to customize, upgrade, and break our devices. It’s fun for us. It’s no surprise that hackers have been jail breaking these devices to see what else they are capable of. A side effect of these hacks is that content can be downloaded directly from Google Play. USB playback can also be enabled. This makes the device more useful to the consumer, but obviously is not in line with Amazon’s business strategy.

Amazon’s response to these hacks was to release a firmware update that will brick the device if it discovers that it has been rooted. It also will not allow a hacker to downgrade the firmware to an older version, since this would of course remove the root detection features.

This probably doesn’t come as a surprise to most of us. We’ve seen this type of thing for years with mobile phones. The iPhone has been locked to the Apple Store since the first generation, but the first iPhone was jailbroken just days after its initial release. Then there was the PlayStation 3 “downgrade” fiasco that resulted in hacks to restore the functionality. It seems that hackers and corporations are forever destined to disagree on who actually owns the hardware and what ownership really means. We’re locked in an epic game of cat and mouse, but usually the hackers seem to triumph in the end.

Connected Thermostat

Raspberry PiPhone Thermostat Monitors Your Entire House — Or At Least That’s The Plan

December 6, 2014 by 18 Comments

[Jeff McGehee] or how he likes to be known, [The Nooganeer] just finished his first big tech project after finishing grad school. It’s a connected thermostat that makes use of his old iPhone 4, and a Raspberry Pi.

Ever since [The Nooganeer] bought his first home with his wife back in the spring of 2014, he’s had ever consuming dream of adding home automation to every appliance. As he puts it…

Home automation has always been a fascination of mine.  How much time and irritation would I save if I didn’t have to worry about turning things on and off, or wonder in which state they were left?  How much more efficient would my home be?  Wouldn’t it be cool to always know the state of every power consumer in my home, and then be able to record and analyze that data as well?

His first challenge was making a smart thermostat — after all, heating and cooling your house typically takes the most energy. Having used a Raspberry Pi before he figured it would be the best brain for his system. After researching a bit about HVAC wiring, [The Nooganeer] settled on a Makeatronics Solid State Relay board to control the HVAC. This allows him to use the GPIO’s on the Raspberry Pi in order to control the furnace and AC unit.  Continue reading “Raspberry PiPhone Thermostat Monitors Your Entire House — Or At Least That’s The Plan” →

Scanning On The Cheap

December 6, 2014 by 20 Comments

[Will] recently stumbled across the MakerBot Digitizer, a device that’s basically a webcam and a turntable that will turn a small object into a point cloud that can then be printed off on a MakerBotⓇ 3D printer. Or any other 3D printer, for that matter. The MakerBot Digitizer costs $800, and [Will] wondered if he could construct a cheaper 3D scanner with stuff sitting around his house. It turns out, he can get pretty close using only a computer, a webcam, and a Black and Decker line laser/level.

The build started off with a webcam mounted right next to the laser line level. Software consisted of Python using OpenCV, numpy, and matplotlib to grab images from the webcam. The software looks at each frame of video for the path of the laser shining against the object to be scanned. This line is then extracted into a 3D point cloud and reconstructed in MeshLab to produce a 3D object that might or might not be 3D printable.

This is only [Will]’s first attempt at creating a scanner. He’s not even using a turntable with this project – merely manually rotating the object one degree for 360 individual frames. It’s extremely tedious, and he’ll be working on incorporating a stepper motor in a future version.

This is only attempt number 1, but already [Will] has a passable scanned object created from a real-world thing.

Bicycle Generator with Cordless Drill

Cordless Drill Turned Into Bicycle-Powered Generator

December 6, 2014 by 27 Comments

The bicycle is a great invention. It is an extremely efficient method of transportation, even more so than walking. So why not harness that efficiency for other things? [Tony] had that same thought so he ordered a bike generator but after waiting too long for the company to send it, he decided to make his own.

[Tony] is an bicycle enthusiast so he had an old bike and an old training stand he could use for the project. Generating electricity from pedaling the bike requires some sort of generator. Lucky for him, [Tony] happened to have a cordless drill that stopped going in reverse. Since he had since upgraded, this was the perfect candidate for the generator. The drill was mounted to the training stand so that a pulley inserted in the chuck pressed against the rear wheel. Wires were added to connect the drill’s battery connectors to a 12vdc to 120vac inverter. As the bike is pedaled, the rear wheel spins the drill, which spins the drill motor creating DC voltage. That DC voltage is then converted to AC by the inverter. With a multimeter connected to the output from the drill, it is easy to adjust the pedaling speed to keep the output in the 11-14v range which is required by the inverter.

In the photo above, you can see a light bulb being powered by the bike. However, the bike powered generator could not power the larger load of a computer. The remedy for this was to purchase a solar charge controller and a 12 volt battery. The bike charges the battery and the battery can power the computer through the inverter.

Chaos Computer Club (and Hackaday) Blocked By British Porn Filters

December 6, 2014 by 59 Comments

The Chaos Computer Club, Europe’s largest association of hackers and hackerspaces, has been blocked by several UK ISPs as part of a government filter to block adult content.

Since July, 2013, large UK ISPs have been tasked with implementing what has been dubbed the Great Firewall of Britain, a filter that blocks adult content, content related to alcohol, drugs, and smoking, and opinions deemed ‘extremist’ by the government. This is an opt-out filter; while it does filter out content deemed ‘unacceptable’, Internet subscribers are able to opt out of the filter by contacting their ISP.

Originally envisioned as a porn filter, and recently updated with list of banned sexual acts including spanking, aggressive whipping, role-playing as non-adults, and humiliation, the British Internet filter has seen more esoteric content blocked from British shores. Objectionable material such as, “anorexia and eating disorder websites,” “web forums,” “web blocking circumvention tools”, and the oddly categorized, “esoteric material” are also included in the filter.

A site built by the Open Rights Group is currently tracking which ISPs blocking which domains. http://ccc.de is currently blocked by ISPs Three and Vodafone. Interestingly, this site – Hackaday – is blocked by the ‘Moderate’ British Telecom filter. The ‘Light’ BT filter – and all other British ISPs – still somehow let Hackaday through, despite posts about building shotguns cropping up from time to time.

UPDATE: Upon reflection, it comes to my attention that Brits have a choice of ISP.

extending an ebike

Extending The Range Of An Electric Bike

December 6, 2014 by 19 Comments

Cruising around town on your electric bike is surely a good time…. unless your bike runs out of juice and you end up pedaling a heavy bike, battery, and motor back to your house. This unfortunate event happened to Troy just one too many times. The solution: to extend the range of his electric bike without making permanent modifications.

Troy admits his electric bike is on the lower side of the quality scale. On a good day he could get about 15 miles out of the bike before it required a recharge. He looked into getting more stock battery packs that he could charge and swap out mid-trip but the cost of these was prohibitive. To get the extra mileage, Troy decided on adding a couple of lead-acid batteries to the system.

The Curry-brand bike used a 24vdc battery. Troy happened to have two 12v batteries kicking around, which wired up in series would get him to his 24v goal. The new batteries are mounted on the bike’s cargo rack by way of some hardware store bracketry. The entire new ‘battery pack’ can be removed quickly by way of a few wing nuts.

Connecting the new batteries to the stock system go a little tricky and the stock battery pack did have to be modified slightly. The case was opened and leads were run from the positive and negative terminals to two new banana plugs mounted in the battery pack’s case. The leads from the new batteries plug right into the banana plugs on the stock battery pack. The new and old batteries are wired in parallel to keep the voltage at 24.

Troy found that he’s getting about twice the distance out of his new setup. Not to bad for a couple on-hand batteries and a few dollars in odds and ends.