Older hackers will remember that a crystal set radio receiver was often one of the first projects attempted. Times have changed, but there’s still something magical about gathering invisible signals from the air and listening to the radio on a homemade receiver. [mircemk] has brought the idea right up to date by building an FM radio with an OLED display, controlled with a rotary encoder.
The design is fairly straightforward, based as it is on another project that [mircemk] found on another site, but the build looks very slick and would take pride of place on any hacker’s workbench. An Arduino Due forms the heart of the project, controlling a TEA5767 module, an SH1106 128×64 pixel OLED display and a rotary encoder. The sound signal is passed through an LM4811 headphone amplifier for private listening, and a PAM8403 Class D audio amplifier for the built-in loudspeaker. The enclosure is made from PVC panels, and accented with colored adhesive tape for style.
It’s easier than ever before to quickly put together projects like this by connecting pre-built modules and downloading code from the Internet, but that doesn’t mean it’s not a worthwhile way to improve your skills and make some useful devices like this one. There are so many resources available to us these days and standing on the shoulders of giants has always been a great way to see farther.
We’ve shown some other radio projects using Arduinos and the TEA5767 IC in the past, such as this one on a tidy custom PCB, and this one built into an old radio case.
Continue reading “DIY Arduino Due TEA5767 FM Radio”
While repairing his Neato Botvac D85, [elad] noticed the little fellow was packing a real speaker and not just a piezo buzzer. Thinking this was a bit overkill just for the occasional beep and bloop, he decided to round things out with a Bluetooth receiver and a second speaker so the bot can spin some stereo tunes while it gets down and dirty.
It wasn’t a very expensive modification. Between the VHM-314 Bluetooth receiver, the 3 watt PAM8403 amplifier, and a matching speaker, [elad] says he was only a few bucks out of pocket. Truly a small price to pay for a robotic vacuum that plays its own theme music as it travels around the house. A small demonstration of the Neato’s new musical talents can be heard in the video after the break.
Perhaps unsurprisingly, the audio hardware puts enough of a drain on the robot’s batteries at max volume that there’s a noticeable reduction in runtime. He’s not too worried about it right now, but [elad] mentions that if it ends up keeping the vacuum from being able to complete it’s whole cleaning cycle, that he might look into adding a dedicated power source to keep the music going.
Despite some early encouragement from iRobot, we haven’t seen quite as much robot vacuum hacking as you might think. It’s always interesting to get a glimpse inside of these automated housekeepers, especially when it’s a custom built machine.
Continue reading “Modded Robot Vacuum Can Whistle While It Works”
Have you ever looked at modern LED lighting and noticed, perhaps on the very edge of your perception, that they seemed to be flickering? Well, that’s because they probably are. As are the LEDs in your computer monitor, or your phone’s screen. Pulse width modulation (PWM) is used extensively with LEDs to provide brightness control, and if it’s not done well, it can lead to headaches and eyestrain.
Looking to quantify just how much flashing light we’re being exposed to, [Faransky] has created a simple little gadget that essentially converts flashing light into an audio tone the human ear can pick up. Those LEDs might be blinking on and off fast enough to fool our eyes, but your ears can hear frequencies much higher than those used in common PWM solutions. In the video after the break, you can see what various LED light sources sound like when using the device.
The electronics here are exceptionally simple. Just connect a small solar panel to an audio amplifier, in this case the PAM8403, and listen to the output. To make it a bit more convenient to use, there’s an internal battery, charger circuit and USB-C port; but you could just as easily run the thing off of a 9 V alkaline if you wanted to build one from what’s already in the parts bin.
Who knows? If you carry this thing around long enough, you might even hear the far less common binary code modulation in action (but probably not).
Continue reading “Flicker Detector Lets You Hear What You Can’t See”