Dumpster Dive Speaker Results In Tube Amplifier

March 18, 2017 by 14 Comments

[Michael Wiebusch] found the leftovers of a wrecked vintage tube radio in a pile of electronics junk. Unfortunately, he could not recover any vacuum tubes in it. And to his dismay, it didn’t even have the output transformer, which he figured would have been useful in a guitar amplifier project. The output transformer is not easy to come by nowadays, so he was hoping to at least score that item for his future build. All he could dig out from his dumpster find was a pair of speakers and he ended up building nice Output-Transformer-Less Tube Guitar Amplifier around them.

Valve output stages are generally high-impedance which means they cannot be directly interfaced to low impedance speakers. An impedance matching output transformer is thus used to interface the two. Back in the day when valves were still the mainstay of audio electronics, many cheap amplifier designs would skimp on the output transformer to save cost, and instead use high impedance speakers connected directly to the amplifier output.

[Michael] found a nice reference design of an OTL amplifier for a 620 ohm single speaker. He decided to use the same design but because these speakers were about 300 ohm each, he would have to wire his two speakers in series. At this point, he decided to make his build useful as a proper guitar amplifier by adding a preamplifier stage replicated from another design that he came across. A regular halogen lamp 12V transformer takes care of the heater power supply for all the tubes, and a second, smaller 12V transformer is wired backwards to provide the 300V needed for the plate supply.

The final result is pretty satisfactory, considering that it all started with just a pair of junked speakers. Check out the result in the video after the break.

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Line Follower Has Lots Of Recycled Parts, But Zero Brains

March 18, 2017 by 20 Comments

Line Followers are a tried-and-true type of robot; both hardware and software need to be doing their job in harmony in order to be successful at a clearly defined physical task. But robots don’t always have microcontrollers and software, as [Mati_DIY]’s zero programming analog line follower demonstrates.

For readers used to seeing a Raspberry Pi or Arduino in almost everything, an analog robot whose “programming” exists only as a harmony between its discrete parts can be an eye-opener as well as an accessible project. A video of the robot in action is embedded below.

[Mati_DIY]’s design uses two CNY70 reflective sensors (which are essentially infrared emitter/phototransistor pairs) and an LM358 dual op-amp. Together, the sensors act as two near-sighted eyes. By using the output of each sensor to drive a motor via a transistor, the presence or absence of the black line is directly and immediately reflected by the motion of the attached motor. The more black the sensor sees, the more the motor turns. Electrically, that’s all that happens; but by attaching the right sensor to the left motor and the left sensor to the right motor, you get a robot that always tries to keep the black line centered under the sensors. Playing with the spacing of the motors and sensors further tweaks the performance.

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Hackaday Unconference Begins!

March 18, 2017 by 3 Comments

This afternoon we are hosting the Hackaday Unconference in three locations at once. Hundreds of creative minds are coming together in Chicago, Los Angeles, and San Francisco for an amazing day of shared inspiration.

You can get a little taste of what is happening by following along with the pulse of the events. Each will be doing some Facebook Live streams so look for that and regular posts on Hackaday Facebook. We’ll be regularly Tweeting and posting to Instagram. It would be absolutely fantastic if you would like and share those messages. Check out the Hackaday TweetWall for a collection of all the #HackadayUncon updates.

The goal is to break down barriers for sharing great ideas which will become the inspiration for new projects to come. Today’s overarching theme is “Build Something That Matters. Everyone attending is ready to give an eight-minute talk about something that interests them, without the pressure of a strict talk order or expectations of polished decks and eloquent delivery. As the Unconference progresses, new discussion groups and impromptu talks take bloom as everyone in attendance guides the direction of the day.

Welcome To The Drone Wars

March 18, 2017 by 18 Comments

“DroneClash” is a competition to be held on December 4th (save the date!) in a hangar at Valkenburg airfield in the Netherlands. The game? Teams try to destroy each others’ quadcopters, navigate through a “Hallway of Doom, Death, and Destruction”, and finally enter a final phase of the game where they try to defend their “queen” drone while taking out those of their opponents.

This sounds like crazy and reckless fun. Surprisingly, it’s being sponsored by the Technical University of Delft’s Micro Air Vehicle (MAV) lab. The goal is to enable a future of responsible drone use by having the ability “to take them out if necessary”.

Drone development has grown hugely in recent years, and you can see the anti-drone industry growing too. Ideally, these developments keep each other in check and result in a safe and responsible incorporation of drones in our daily lives. We are organising DroneClash to generate new ideas in order to encourage this process.

We do have to ask ourselves why anyone would want to use another quadcopter to take out illegally operated quadcopters — there must be a million more effective means from a policing standpoint.  On the other hand, if we were re-shooting “Hackers” right now, and looking for a futuristic sport, we would swap out rollerblading for drone combat. Registration opens this week. Gentlebots, start your engines.

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Configure ESP8266 Wifi With WiFiManager

March 18, 2017 by 39 Comments

There’s no doubt that the ESP8266 has made creating little WiFi widgets pretty easy. However, a lot of projects hard code the access point details into the device. There’s a better way to do it: use the WiFiManager library. [Witnessmenow] has a good tutorial and a two-minute video (which you can see below).

Hard coding is fine if you are just tinkering around. However, if you are going to send your device away (or even take it with you somewhere) you probably don’t want to reprogram it every time you change access points. This problem is even worse if you plan on a commercial product. WiFiManager does what a lot of commercial devices do. It initially looks like an access point. You can connect to it using a phone or other WiFi device. Then you can configure it to join your network by setting the network ID, password, etc.

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Modern Wooden Houses With No Glue Or Nails

March 18, 2017 by 94 Comments

Depending where you are in the world, the techniques used to build houses can sometimes seem to be stuck in another century. Bricks and mortar, for instance, we build with them because we are used to them and have a large workforce of people trained to work with them and not much else. But in the 21st century with more advanced building technologies sitting relatively unused and looming housing crises at every turn, does it make sense to still build houses the slow and expensive way our great-grandparents did? Probably not.

Wooden houses are a promising solution to some of the problems outlined in the previous paragraph, and indeed in large parts of the world wood is the housing material of choice. It’s eco-friendly, not too expensive, and can be applied easily to multiple different types of structure. If you think of a wooden house, does the image of a log cabin come to mind, or perhaps a weatherboard house? Both construction methods that would be familiar again to your great-grandparents, so perhaps you might not call it an advanced building technology.

It’s interesting then to see an innovation from France, a system of interlocking wood sections that can be built into walls that look very similar to brick (Here’s the French language original). These are short sections of board cleverly designed with dovetailing to engage with vertical sections that interlock between different courses and leave a gap between wooden inner and outer faces of the wall that can be filled with insulation material. The effect is to create a wooden building system that can produce a vast range of structures that can be assembled in a very short time indeed. This isn’t prefabricated housing, but it delivers the speed you’d expect from it.

They have a video shoving construction of a typical house in rather idyllic French countryside, which we’ve put below the break. It has French language annotations, however for non Français speakers the context is pretty obvious.

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A Wireless Oscilloscope Isn’t As Dumb As It Sounds

March 18, 2017 by 38 Comments

The latest CrowdSupply campaign is a wireless, Bluetooth oscilloscope that doesn’t make a whole lot of sense until you really think about it. Once you get it, the Aeroscope wireless oscilloscope is actually a pretty neat idea.

If the idea of battery-powered, Bluetooth-enabled test and measurement gear sounds familiar, you’re not dreaming. The Mooshimeter, also a project on CrowdSupply, is a multichannel multimeter with no buttons, no dial, and no display. You use the Mooshimeter through an app on your phone. This sounds like a dumb idea initially, but if you want to measure the current consumption of a drone, or under the hood of your car while you’re driving, it’s a really, really great idea.

The specs of the Aeroscope aren’t bad for the price. It is, of course, a one-channel scope with 20 MHz bandwidth and 100Msps. Connection to the device under test is through pokey bits or grabby bits that screw into an SMA connector, and connection to a display is over Bluetooth 4.0. You’re not getting a scope that costs as much as a car here, but you wouldn’t want to put that scope in the engine bay of your car, either.

The Aeroscope is currently on CrowdSupply for $200. Compared to the alternatives, that’s a bit more than the no-name, USB scopes. Then again, those are USB scopes, not a wireless, Bluetooth-enabled tool, and we can’t wait to see what kind of work this thing enables.