The camera in a typical mobile phone is now at a standard at which it can be considered a serious device rather than a toy, such has been the effort put in by the phone manufacturers. They are still held back in some ways by their lenses despite the same development effort being pointed in that direction, and there have been projects aiming to replace those lenses with better quality ones. A while back we covered [Evan Monsma]’s replacement of his broken iPhone camera lens with a C-mount item, and now he’s back with a much improved version.
The original was glued on with cyanoacrylate adhesive, and this had parted. It was time to upgrade the phone, so he had a new lens mount covering two of the cameras machined from solid brass and leaving an open view for the third and unmodified camera. This was fixed to the phone with epoxy, and with a set of 3D printed lens covers to protect them he’s ready to go. There’s even a tripod thread machined into the bottom of this thing. He shows us it in action with both C-mount and EF-mount lenses, the latter resulting in a very long effective focal length.
We like this project, but perhaps we’d give it an IR filter to remove the unwanted pink glow. If you’re interested, here’s the original version.
I started writing this from a commuter train passing at speed through the outskirts of London, and my headset had just broken. The flexible joint that attaches one earpiece to the headband has snapped, leaving the earpiece dangling on its cable. This is annoying on its own, but what is annoying me enough to write about it is that this isn’t the first time. This is only the latest in a succession of headsets I’ve taken on the road with me has broken, not because of rough treatment, but simply due to flimsy or bad design. What on earth can I do about this?
Failure Built-In
Failure inevitable: the whole headset relied on a tiny piece of plastic in the centre.
The most recent three have been a JVC whose rotating joint allowing the earpiece to lie at a slight angle with my ear has failed, a quite expensive Logitech whose ear sponges failed closely followed by its USB cable, and now an EPOS whose ball joint has failed.
I repaired the JVC and got a bit more life out of it and I’ll have a go at repairing this EPOS, but that’s hardly the point. I’m paying not inconsequential money and I’m getting good sound quality and electronics, but I’m not getting anywhere near the mechanical quality I need. I could buy a set of tough DJ headphones such as the Sennheiser HD25, but they don’t come with a microphone, they’re not a headset.
So if I can’t buy a decent headset without spending military grade money on one from an F16 fighter, what can I do to make my own? I’m an engineer, damnit!
At its most basic, a headset is a springy band that goes over the head, with an earpiece at its end. But a human head is not a cube with vertical parallel sides, it’s a complex shape and every one is different. So those earpieces have to have some “give” in them in order to fit comfortably against the ear. In the simplest case this is achieved by giving the earpiece a soft surround that moulds itself to the ear, but most headsets incorporate some articulation. The earpiece must rotate a little around a vertical line parallel with the ear, and also with a horizontal line at right angles to the axis of the ear. The EPOS managed both axes by means of a ball joint, while the JVC had a stirrup with pins to achieve the horizontal motion, and a circular joint — the part which broke — for the vertical. In both case the weak point was a thin part of the plastic moulding which broke, on the EPOS a short stalk for the ball in the ball joint, and in the JVC a similar stalk for the circular joint. Any design I come up with must avoid this type of weak point, and spread the load of an earpiece over considerably more material than my broken headset. Continue reading “A Headset Fit For A Hackaday Writer”→
USB-C Power Delivery (PD) has been a boon to anyone working with low-voltage DC power, because at a stroke it replaces a vast array of wall warts, power supplies, and connector standards with one simple and straightforward commoditized system. But with varying capabilities between sources and sinks, it can be difficult to know what’s going on.
[Marco Tabini] has created Dr. PD, a USB -C PD protocol analyzer. It can sit between USB-C PD source and sink, or emulate a sink in order to characterize a source. It supports an impressive range of USB power protocols, and can work up to the full 48 volt/240 watt limits of the technology. The project is open source and is to be the subject of a crowdfunding campaign should you want one without the extra work.
It’s likely that many of you will have had bad experiences with cheap USB-C PD gear failing to follow standards, being unable to handle the specified current, or just plain supplying the wrong voltage. We have, and while USB-C PD is genuinely a great technology, this regrettable hardware represents its grubby underbelly. This is just the project we need on the bench in our hackerspace.
There are some projects that seem at first sight to be easy, but anyone who tries them finds a whole heap of unexpected problems and turns to the off-the-shelf device. PCB antennas for example, or data links using LEDs, whether IR or visible. The latter doesn’t faze [Luca Soltoggio] though, because he has two ESP32s talking to each other using visible light. Best of all, both use a single LED as both transmitter and receiver.
The software is called SecurePair, and is an Arduino library for exchanging keys and communicating with encryption. The LEDs are the cool hardware hack but it’s designed to work with ESPNow or LoRa too, indeed a typical use case would see light for pairing and wireless for the exchange of encrypted data.. In case you were wondering, it relies on the property of an LED that it’s also a photodiode of sorts. Best of all, while the examples have two ESP32s, it’s not limited to that number and many more can join the conversation if needed.
Check out the video below to see it in action — if you’re curious about LEDs as sensors, we’ve been there too.
Perhaps the most famous of all the software-defined radio (SDR) receivers is the RTL-SDR, a digital TV receiver on which an undocumented feature was found. Perhaps other radio-enabled chips also have the same undocumented feature? It seems in the case of some members of the ESP32 family, they do. It’s a discovery made independently in two places, by Espargos, and a Reddit user by the name of h0m3us3r.
What’s happening is that the undocumented mode taps the I/Q stream off before the WiFi modem, and this can be read and processed by SDR software on an external computer. The undocumented mode can be found on ESP32 chips with the earlier Tensilica hardware onwards, so the low power Bluetooth only chips or the non-radio-equipped P4 won’t work. Sadly it’s also only possible with the receive side, with both 2.4 and 5 GHz bands being supported depending on the microcontroller in question.
This isn’t quite the general purpose SDR we got with the RTL-SDR, but there are still plenty of uses to which it can be put. We’re curious as to whether someone can implement the software side of an SDR on the same chip, but we are guessing that might be beyond their capabilities. Either way, we’re looking forward to what the community does with this new-found knowledge.
[Ogrinz Labs] has built a Robbie the Robot suit, which is super-cool, but has a huge flaw. When inside the suit, he’s too tall to do what the original Robbie actor did, which was to look through the “mouth” grille. He solved this with an inexpensive automotive reversing camera, but then realised its monitor had a built-in on-screen-display chip. After a lot of work, he’s published a GitHub repository that allows access to this thing for custom on-screen graphics.
The chip in question is an AMT630A, which contains video switching hardware, a graphics system for the on-screen-display, and an 8052 microcontroller core. He didn’t manage to get into the 8052’s brain, but the video below details the long path towards controlling it through an I2C port with an ESP32. The software is available as an Arduino library. His intention is to use it as a display for navigational sensor data to aid in maneuvering Robbie.
Internet radios have been a thing in some form for the last quarter century, and the advent of cheap networked microcontrollers has made them easier than ever to build. But just how small can one be made? [Milen] has made one that’s about as small as we’ve seen, and put it up on Instructables.
The hardware recipe is straightforward enough; take a microcontroller, connect it to the internet, and have your internet radio software squirt its output to a DAC. In this case the microcontroller is an ESP32-C£ on a very small dev board, and clipped to that is a custom PCB with a PCM5102A I2S DAC and an amplifier. The whole thing is tiny, small enough in fact that the two connectors are significant in size compared to it.
Whether or not it’s a practical device for listening remains to be seen, but it’s certainly tiny. But the question is, could it be made smaller? Perhaps eschewing the connectors would be an easy win, and in return for a loss in quality the ESP has a built-in DAC that’s not intended for audio but can be used. If you have any bright ideas, we’d be interested to hear them.
We’ve seen plenty of internet radios over the years, and for some reason this cassette-shaped one appeals to us.
