Long before audio engineers had fancy digital delays, or even crappy analog delays, there were tape delays. Running a tape around in a loop with a record and play head is the basis of the Echoplex and Space Echo, and both of these machines are incredible pieces of engineering.
Microcassette recorders are not, in general, incredible pieces of engineering. They do, however, have a strip of magnetic tape, a record head, and a play head. Put two of them together, and you can build your own tape delay.
The basic principle of a tape delay is simple enough – just run a loop of tape round in a circle, through a record and playback head, record some audio, and send the output to an amplifier. In practice, it’s not that simple. [dogenigt] had to manufacture his own tape loop from microcassettes, a process that took far too long and was far too finicky.
For a control circuit, [dogenigt] is using four audio pots and one linear pot for speed control. The audio pots are responsible for input gain, feedback, the amplitude of the clean signal, and the output of the signal after it’s been run through the delay.
Apart from being one of those builds that’s very dependent on the mechanical skill of the builder, it’s a pretty simple delay unit, with all the electronics already designed for a stripboard layout. You can hear an example of what it sounds like below.
Continue reading “Microcassette Recorders Become A Tape Delay”
The Amazon Echo is the answer to Apple’s Siri, Microsoft’s Cortana, and [Orwell]’s Telescreen – a device that sits in your home, listens to everything you say, and will gladly oblige if you want to buy something on Amazon. Brilliant. Despite being a pretty cheap device, there’s not really a whole lot it can do; sure, Echo, or more accurately Alexa, the personality in the Echo, can tell you the weather, queue up a playlist, or read a Wikipedia entry, but there’s a definite lack of imagination when it comes to the Echo.
Now, thanks to some clever API hacks, you can do far more with the Echo. [Noel] is using the Echo to turn lights in his house on and off, ring his home phone, and basically everything else you can do with some wire and a bit of code.
[Noel] got his idea from [Owen Piette] who recently investigated the Echo API. It’s all unpublished by Amazon, but it is possible to poll the todo list for random key phrases. By polling this API and getting new results, it’s pretty easy to set up some logic to do arbitrary actions.
Right now [Noel] can turn a light on and off and call his phone, but the sky really is the limit here. If you have a web-enabled thermostat, Alexa can turn the heat on or off. Want to text yourself something? That’s easy too. Anything that can be put in a todo list can be done with the Echo, the only obstacle is doing all the programming and electronics.
We’re familiar with features like Siri or Microsoft’s Cortana which grope at a familiar concept from science fiction, yet leave us doing silly things like standing in public yowling at our phones. Amazon took a new approach to the idea of an artificial steward by cutting the AI free from our peripherals and making it an independent unit that acts in the household like any other appliance. Instead of steering your starship however, it can integrate with your devices via bluetooth to aide in tasks like writing shopping lists, or simply help you remember how many quarts are in a liter. Whatever you ask for, Echo will oblige.
The device is little more than the internet and a speaker stuffed into a minimal black cylinder the size of a vase, oh- and six far-field microphones aimed in each direction which listen to every word you say… always. As you’d expect, Echo only processes what you say after you call it to attention by speaking its given name. If you happen to be too far away for the directional microphones to hear, you can alternatively seek assistance from the Echo app on another device. Not bad for the freakishly low price Amazons asking, which is $100 for Prime subscribers. Even if you’re salivating over the idea of this chatting obelisk, or intrigued enough to buy one just to check it out (and pop its little seams), they’re only available to purchase through invite at the moment… the likes of which are said to go out in a few weeks.
The notion of the internet at large acting as an invisible ever-present swiss-army-knife of knowledge for the home is admittedly pretty sweet. It pulls on our wishful heartstrings for futuristic technology. The success of Echo as a first of its kind however relies on how seamlessly (and quickly) the artificial intelligence within it performs. If it can hold up, or prove to hold up in further iterations, it’s exciting to think what larger systems the technology could be integrated with in the near future… We might have our command center consciousness sooner than we thought.
With that said, inviting a little WiFi probe into your intimate living space to listen in on everything you do will take some getting over… your thoughts?
Continue reading “Echo, the First Useful Home Computer Intelligence?”
If you’d like to start experimenting in DSP, or just want to build a guitar pedal, here’s the project for you. It’s an audio echo using just a microcontroller from the fruitful workshop of [Vinod].
For his circuit, [Vinod] fed the output of a small electret microphone into a small amplifier, and then into the ADC of an ATMega32. Inside the microcontroller, [Vinod] set up a circular array which writes the voltage from the microphone and sends it out to a speaker. Because the array is circular (i.e. it loops around when it gets to the end), [Vinod] has a digital version of a loop of magnetic tape, perfect for recording sounds and playing back echos.
Because [Vinod] is using an ATMega32, he only has a limited amount of RAM to record audio samples. The delay time could be lengthened with a more capable microcontroller, or even the addition of a large RAM chip. With his setup, [Vinod] can do some really interesting experiments with audio and DSP, so we wouldn’t be surprised if an enterprising musician used this project as the basis for a digital delay stomp box.
You can check out [Vinod]’s demo of his echo machine after the break.
Continue reading “Making a digital delay from a simple microcontroller”
Professional tape delay units are great fun, but often expensive. You’d think that with so many derelict cassette decks filling the world’s dumpsters someone must have figured out a way to make a cheap tape delay… not only in the interest of saving money (sometimes quality is worth paying for) but also in the interest of re-using otherwise wasted resources.
Forosdeelectronica forum user [Dano] has made just such a device from used cassette decks and miscellaneous parts (translated). First he investigated the operation of the playback, erase, and record mechanisms and broke out the tape heads. The playback head is on a plastic rail so that the delay time can be changed, while the record head is fixed. [Dano] encountered some difficulties in ensuring good quality for the recording and erasure, which is an important consideration when working with magnetic tape.
Continue reading “Tape delay made from recycled cassette decks”
[Vsergeev] built an echo pedal for a guitar or with other audio manipulation applications. He used an mbed microcontroller for the project. You may remember Hackaday writer [Phil] labeling the mbed an ‘Arduino on steroids’, and it certainly handles this audio processing quite well. We’ve included a clip of the echo effect after the break. During the design process, [Vsergeev] used LTspice to simulate the analog circuitry and make things right before committing to the physical circuits.
Continue reading “Guitar echo pedal built with mbed”