This is a very simple project and most of the parts are off the shelf. Hardware wise the monster’s body is made out of a plastic flowerpot; its mouth is a bit of wood that covers the top of the flowerpot; its eyes, two halves of a plastic sphere painted white with some felt for irises. And then whole thing is covered in some blue fake fur.
Electronics wise, a Raspberry Pi is running the show and handling the text-to-speech is an AIY Voice Hat. A servo fits inside the flowerpot to open and close the monster’s mouth. On the software end of things, a bit of Python has been written that waits for a bit of text, sends it off to the Voice Hat’s text-to-speech module and moves the servo to open and close the mouth. The scary part, connecting the monster to the internet, is done with remo.tv, which is some open-source code hosted on GitHub specifically for allowing control of robots over the internet.
This is a neat little project which is simple enough that kids could build one themselves. The instructions and the python script are up on the Instructables page, and you can see the monster in action at its page on remo.tv. Perhaps [8BitsAndAByte] could add a couple of these internet controlled robot arms to the monster to create a monster that could create some real havoc!
There’s an old saying that we have one mouth and two ears so you can listen twice as much as you talk. However, talking and listening at the same time is fairly difficult and doing it with radio signals is especially hard. A company called Kumu Networks has an analog module that can use self-interference cancellation which allows transmitting and receiving on the same frequency with around 50 dB of the transmitted signal in the transceiver. You can see a video about Kumu’s claims its technology below.
You may think that cell phones and ham radio repeaters transmit and receive at the same time, which of course they do, but usually on different frequencies to avoid direct interference. A diplexer is a device that sorts out the two frequencies while a duplexer sorts them out by the direction of the signal, but they are tricky to use. A duplexer can operate on a single frequency in applications such as radar, and even then it is still very difficult to prevent leakage from the transmitter from overloading and desensitizing the receiver.
Thermoelectric devices are curious things, capable of generating electricity via the Seebeck effect from a temperature differential across themselves. The Seebeck effect does not produce a huge potential difference, but when employed properly, it can have some useful applications. [MJKZZ] decided to apply the technology to build a reading light, powered by a hot cup of coffee.
The build is based around four Peltier modules, 40mm x 40mm in size, sandwiched between a pair of copper sheets. The modules are wired in series to create a greater output voltage, and an aluminium heatsink is fitted to one side to create a higher temperature differential. The set-up produces just 230 mV from human body temperature, but over 8 volts when warmed directly with a heat gun. Boiling water in a mug produces a more restrained 2.1V output.
On its own, this voltage is a little weak to do anything useful. Thus, the electricity from the Peltier modules is fed through a joule thief, which helps step up the voltage to a more useful range to run an LED. With a mug of coffee on the copper plate, the assembly isn’t quite able to light the LED enough to allow the user to read comfortably. However, it flickers into life just a touch, demonstrating the basic concepts in action.
While it’s not the most practical build, and it’s likely to cool your coffee faster than you’d like, it’s a fun project that serves to educate about the mechanics of the Seebeck effect and using Peltier devices to generate it. Another fun application is to use them in a cloud chamber. Video after the break.
The station’s user interface was kept intentionally simple, with little more than a four digit LED display to show the temperature and a rotary encoder to set it. The display alternates between the current temperature and the set temperature every few seconds while the knob is being turned, and if you push it in, the set temperature will be saved as the default for next time.
[MarcelMG] also included a feature that drops the iron’s temperature when it’s sitting in the holder, reducing tip wear and energy consumption. He originally planned on using a Hall effect sensor to detect when the iron was holstered without needing to physically interface with it, but in the end he realized the easiest approach was to simply connect one of the input pins on the microcontroller to the metal holder. Since the tip is grounded, he could easily detect if it was in place with a couple lines of code.
Speaking of which, the station is powered by an ATtiny24A with firmware written in C using the Atmel Studio IDE. [MarcelMG] mentions that the limited storage on the 24A was a bit of a challenge to work around, and suggests that anyone looking to follow in his footsteps uses something with a bit more flash under the hood. The LED display is a very common TM1637 type, the rotary encoder was salvaged from a radio, and the power supply was from an old laptop. All told, this looks like a very economical build.
The tape recorder was an invention that kicked off a golden period of exploration in sound. Beginning in World War II, the Nazi propaganda machine cut and spliced recorded materials and disseminated them across broadcasting stations in Europe. To the astonishment of the Allies, certain German officials appeared to be making broadcasts from different studios at the same time, due to the high quality of the recording hardware. After the war, this technology was discovered by a group of Parisian recording artists who began to experiment with an art that became known as musique concrète, using tape hardware in weird and wonderful ways to create new sounds heretofore unheard in nature.
If there’s one thing that gives us joy here at Hackaday it’s a story of audio silliness. There is a rich vein of dubious products aimed at audiophiles which just beg to be made fun of, and once in a while we oblige. But sometimes an odd piece of audio equipment emerges with another purpose. Take [Boltz999]’s interconnects for example, which were born of necessity when there were no female-to-female phono adapters to connect a set of cables. Taking a baby carrot and simply plugging the phonos into its flesh delivered an audio connectivity solution that worked.
Does this mean that our gold-nanoparticle-plated oxygen-free directional audio cables are junk, and we should be heading for the supermarket to pick up a bag of root vegetables instead? I set out to test this new material in the secret Hackaday audio lab, located on an anonymous 1970s industrial estate in Milton Keynes, UK.
Chances are pretty good that most of us have used a bench vise to do things far beyond its intended use. That’s understandable, as the vise may be the most powerful hand tool in many shops, capable of exerting tons of pressure with the twist of your wrist. Not taking advantage of that power wouldn’t make any sense, would it?
Still, the clamping power of the vise could sometimes use a little finesse, which is the thinking behind these 3D-printed press brake tools. [Brauns CNC] came up with these tools, which consist of a punch and a die with mating profiles. Mounted to the jaws of the vise with magnetic flanges, the punch is driven into the die using the vise, forming neat bends in the metal. [Braun] goes into useful detail on punch geometry and managing springback of the workpiece, and handling workpieces wider than the vise jaws. The tools are printed in standard PLA or PETG and are plenty strong, although he does mention using his steel-reinforced 3D-printing method for gooseneck punches and other tools that might need reinforcement. We’d imagine carbon-fiber reinforced filament would add to the strength as well.
To be sure, no matter what tooling you throw at it, a bench vise is a poor substitute for a real press brake. Such machine tools are capable of working sheet metal and other stock into intricate shapes with as few setups as possible, and bring a level of power and precision that can’t be matched by an improvised setup. But the ability to make small bends in lighter materials with homemade tooling and elbow grease is a powerful tool in itself.