If you walk the halls of audiophilia, you may be aware that there has been a huge amount of work put in to software designed to clean up older audio recordings without compromising the quality of the recording itself. Sometimes the results can be amazing, such as when a stereo image is created from parallel mono recordings made before stereo was even a glint in the eye of a 1930s EMI engineer.
But what if you are at home, without the benefit of a state-of-the-art studio or high-end digital signal processing? How can you then have pop and crackle free sound from your hi-fi when you put on a piece of vinyl? [Paul Wallace] may just have the answer, he’s made a smartphone app called Scratchy which listens to the output of a turntable, identifies the track being played, and plays the appropriate MP3 file for a digital experience from vinyl. It uses the algorithm published by Shazam to recognize tunes. The software also has a learn mode during which it can be taught about new records in the collection. The app itself is written using the Xamarin framework and has its source code in his GitHup repository, so it’s possible it could be produced for other platforms as well as Android.
Now vinyl purists will be speechless with horror at this wanton desecration of their format while audiophiles will be fuming at the smeary-in-the-midrange MP3s, but we can see its appeal if your vinyl is on the grubby side. It’s fair to say though that the stereo here won’t be sporting it, you’ll tear our analogue signal path from our cold dead hands. Take a look for yourselves, he’s put up a video showing it in operation.
The eternal enemy of [James Puderer]’s pockets is anything that isn’t his smartphone. When the apartment building he resides in added a garage door, the forces of evil gained another ally in the form of a garage door opener. So, he dealt with the insult by rigging up a Raspberry Pi to act as a relay between the opener and his phone.
The crux of the setup is Firebase Cloud Messaging (FCM) — a Google service that allows messages to be sent to devices that generally have dynamic IP addresses, as well as the capacity to send messages upstream, in this case from [Puderer]’s cell phone to his Raspberry Pi. After whipping up an app — functionally a button widget — that sends the command to open the door over FCM, he set up the Pi in a storage locker near the garage door and was able to fish a cable with both ethernet and power to it. A script running on the Pi triggers the garage door opener when it receives the FCM message and — presto — open sesame.
[Sergey Mironov] sent in his SelfieBot project. His company, Endurance Robots, sells a commercial version of the bot, which leads us to believe that in a strange and maybe brilliant move he decided to just sell the prototype stage of the product development as a kit. Since he also gave away the firmware, STLs, BOM, and made a guide so anyone can build it, we’re not complaining.
The bot is simple enough. Nicely housed hobby servos in a 3D printed case take care of the pan and tilt of the camera. The base of the bot encloses the electronics, which are an Arduino nano, a Bluetooth module, and the support electronics for power and motor driving.
To perform the face tracking, the build assumes you have a second phone. This is silly, but isn’t so unreasonable. Most people who’ve had a smart phone for a few years have a spare one living in a drawer as back-up. One phone runs the face tracking software and points the bot, via Bluetooth, towards the user. The other phone records the video.
The bot is pretty jumpy in the example video, but this can be taken care of with better motors. For a proof-of-concept, it works. A video of it in action after the break.
Many productive hackers bleed a dark ochre. The prevailing theory among a certain group of commenters is that they’re full of it, but it’s actually a healthy sign of a low blood content in the healthy hacker’s coffee stream. [Bharath] is among those who enjoy the caffeinated bean juice on a daily basis. However, he’d suffer from a terrible condition known as cold coffee. To combat this, he built an app-enabled, wirelessly chargeable, self-heating coffee mug.
We know that most hackers don’t start off planning to build objects with ridiculous feature lists, it just happens. Is there an alternate Murphy’s law for this? Any feature that can be added will? The project started off as some low ohm resistors attached to a rechargeable power bank. A insulated flask with a removable inner stainless steel lining was chosen. The resistors were fixed to the outside with a thermal epoxy.
However, how do we control the resistors? We don’t want to burn through our battery right away (which could end up more literally than one would like), so [Bharath] added a Linkit One microcontroller from Seeed Studio. With all this power at his disposal, it was natural to add Bluetooth, a temperature sensor, and app control to the cup.
After getting it all together, he realized that while the insides were perfectly isolated from the liquids held in the flask under normal use, the hole he’d have to cut to connect to the charging circuit would provide an unacceptable ingress point for water. To combat this he added the wireless charging functionality.
With his flask in hand, we’re sure the mood boost from not having to slog through the dregs of a cold container of coffee will produce a measureable improvement in productivity. Video after the break.
With three kids, including himself, [Dave] faced the very real likelihood of someone absent-mindedly leaving the garage door open and being robbed blind. Rather than installing some plebeian solution, he compiled a feature list. And what a feature list it is!
The garage door needed to notify him of its status with strategically placed LEDs around the house, and give him full control on his devices. He wanted to open and close it using his existing key-code entry system. Lastly, it would be extra-cool if he could add some biometrics to it; in this case, a fingerprint sensor.
The core hardware is the staple Arduino augmented with a fingerprint module, a touch screen, some vitamins, and a WiFi break-out. He also worked up some casings in tinkercad: one for the indoor hardware, another with a flip cover for the outdoor fingerprint scanner.
We think [Dave] has accomplished what he set out to. We can just picture the would-be-thief staring at the finger print scanner and moving their operation one house over where the world is simpler. Video after the break.
App development is not fun for everyone, and sometimes you just want to control a device from your phone with minimal work. Blynk appears to be a fairly put-together library for not only hooking up any Arduino or esp8266 to a phone through WiFi, but also through the net if desired.
Install the app onto your iPhone or Android device. Install the libraries on your computer. Next, modify your Arduino source to either pass direct control of a pin to Blynk, or connect Blynk to a virtual pin inside your code for more advanced control. If you want to go the easy route, create an account, log into the app, and drag and drop the interface you’d like. If the idea of letting some corporation host your Arduino project sends shivers down your spine, there is also an option to host your own server. (Editorial snark: Yes, it requires a server. That’s the cost of “simplicity”.)
There have been a few times where we’ve wished we could add app control to our projects, but installing all the libraries and learning a new language just to see a button on a screen didn’t seem worth it. This is a great solution. Have any of you had experience using it?
This could be the start of a new thing. [HarpDude] showed off his String Car Racers over on the Adafruit forum. It’s like a small model cable car on caffeine. String up enough of them and go head to head racing with others.
A motor with a small pulley runs over a length of string stretched between 2 posts. Below the pulley, acting as a counterweight balance, is the rest of the racer. A Trinket board, motor driver, 9V battery and a pair of long lever micro switches to detect end of travel. The switches also help reverse the motor. A piece of galvanized wire acts as a guide preventing the String Car from jumping off the string. And discovering the benefits of a micro-controller design, as against discrete TTL/CMOS, old timer [HarpDude] added two operational modes via software. “Pong”, where the String Car keeps going back and forth over the string until it stops of (battery) exhaustion. The other mode is “Boomerang” – a single return trip back and forth.
We are guessing the next upgrade would be to add some kind of radio on the car (ESP8266 perhaps) and build an app to control the String Car. That’s when gaming could become fun as it opens up possibilities. One way to improve performance would be to add two “idler” pulleys in line with the main drive pulley, and then snake the string through the three of them. Now you know what to do with all of those old motors you’ve scavenged from tape drives, CD drives and printers. Let the Games begin!