Glowscope Reduces Microscope Cost By Orders Of Magnitude

As smartphones become more ubiquitous in society, they are being used in plenty of ways not imaginable even ten or fifteen years ago. Using its sensors to gather LIDAR information, its GPS to get directions, its microphone to instantly translate languages, or even use its WiFi and cellular radios to establish a wireless hotspot are all things which would have taken specialized hardware not more than two decades ago. The latest disruption may be in microscopy, as this build demonstrates a microscope that would otherwise be hundreds of thousands of dollars.

The microscope is a specialized device known as a fluorescence microscope, which uses a light source to excite fluorescent molecules in a sample which can illuminate structures that would otherwise be invisible under a regular microscope. For this build, the light is provided by readily-available LED lighting as well as optical filters typically used in stage lighting, as well as a garden-variety smartphone. With these techniques a microscope can be produced for around $50 USD that has 10 µm resolution.

While these fluorescence microscopes do have some limitations compared to units in the hundred-thousand-dollar range, perhaps unsurprisingly, they are fairly impressive for such a low-cost alternative. More details about these builds can also be found in their research paper published in Nature. Even without the need for fluorescence microscopy, a smartphone has been shown to be a fairly decent optical microscope, provided you have the right hardware to supplement the phone’s camera.

Photo of a smartphone with the ATTiny85 inserted into it, with a screen unlock pattern being drawn on the screen

ATtiny85 Automates Your Smartphone

It might not seem too impressive these days, but when microcontrollers with hardware USB support were more expensive and rare, the VUSB library was often used to create USB devices with an ATtiny85. It became so popular that the ATtiny85 even got packaged into USB dongle formfactors, like the DigiSpark boards. Well, you might not know this, but your Android smartphones can also work with USB mice and touchscreens in lieu of the built-in touchscreen display. [ErfanSn] combined these two ideas, creating a library to automate smartphone touchscreen events and keyboard input with an ATtiny85 — open for all of us to use, and with examples to spare.

The library is called DigiCombo, and it comes with plenty of examples for any screen touch event emulation that you might want. For instance, check out the README — it has video examples for Instagram page scrolling, unlock screen brute-forcing with random coordinates, playing the Stack rhythm game, and pinch zoom — all the building blocks for your smartphone touch emulation needs are covered pretty well! Of course, all of these have example code corresponding to them, that you can download and base your own ideas on. What’s more, the library is available in current Arduino IDE under the DigiCombo name. So if you need to, say, make a quick autoclicker for your phone, the library is a few steps away!

If your smartphone project was stalled because you needed to emulate touchscreen input, this library is your chance to get it done! We appreciate projects that let us get more from smartphones — there’s a lot of those laying around, they’re pretty functional and self-sufficient devices, so it makes sense that some projects of ours could do with a phone instead of a Raspberry Pi. Some manufacturers let us get a bit more of our phones, but this hasn’t really caught on, which means we have to make do with help of libraries like these. Or, perhaps, you rely on your phone day-to-day, and you’d like to add a touchpad to its back?

Homebrew Telephone Exchange Keeps The Family In Touch, In The House And Beyond

It doesn’t happen often, but every once in a while we stumble upon someone who has taken obsolete but really cool phone-switching equipment and built a private switched telephone in their garage or basement using it. This private analog phone exchange is not one of those, but it’s still a super cool build that’s probably about as ambitious as getting an old step-by-step or crossbar switch running.

Right up front, we’ll stipulate that there’s absolutely no practical reason to do something like this. And hacker [Jon Petter Skagmo] admits that this is very much a “because I can” project. The idea is to support a bunch of old landline phones distributed around the house, and beyond, in a sort of glorified intercom system. The private exchange is entirely scratch-built, with a PIC32 acting as the heart of the system, performing such tasks as DTMF decoding, generating ring voltage, and even providing a CAN bus interface to his home automation system.

The main board supports five line interface daughterboards, which connect each phone to the switch via an RJ11 jack. The interface does the work of detecting when a phone goes off-hook, and does the actual connection between any two phones. A separate, special interface card provides an auto-patch capability using an RDA1846S RF transceiver module; with it, [Jon Petter] can connect to any phone in the system from a UHF handy-talkie. Check out the video below for more on that — it’s pretty neat!

We just love everything about this overengineered project — it’s clearly a labor of love, and the fit and finish really reflect that. And even though it’s not strictly old school, POTS projects like this always put us in the mood to watch the “Speedy Cutover” video one more time.

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A laptop with a desk phone and a 3D-printed acoustic coupler next to it

Acoustic Coupler Gets You Online Through Any Desk Phone

Up until the mid-1980s, connecting a computer to a phone line was tricky: many phone companies didn’t allow the connection of unlicensed equipment to their network, and even if they did, you might still find yourself blocked by a lack of standardized connectors. A simple workaround for all this was an acoustic coupler, a device that played your modem’s sounds directly into a phone’s receiver without any electrical connection. Modem speeds were slow anyway, so the limited bandwidth inherent in such a system was not much of a problem.

Nowadays it’s easier to find an internet connection than a phone line in many places, but if you’re stuck in an ancient hotel in the middle of nowhere you might just find [GusGorman]’s modern take on the acoustic coupler useful. The basic design is quite simple: it’s a 3D-printed box with two cups that fit a typical phone handset and a space to put a USB speaker and microphone. Thanks to minimodem it’s easy to set up a connection with any other computer equipped with a phone connection.

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Virtualizing IPhoneOS 1.0

Virtualizing computers is nothing new. However, Apple devices always present challenges. Just ask anyone who has built a Hackintosh. At least computer hardware is usually exposed, but on phones, the challenge is even harder due to mysterious devices. [Martijn] managed to reverse engineer the iPod Touch 1G enough to run iPhoneOS 1.0 on it and has several blog posts explaining how he did it.

The emulator is the ubiquitous QEMU. He has emulation for the critical hardware, including the cryptographic modules, the hardware clock, and the timer, along with memory and display and interface hardware. However, Wifi, some USB, audio, the light sensor, and some graphics hardware are still absent. That doesn’t stop the OS from booting, however.

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Stack Trace From The 1950s Punches Again

This repair/tutorial video by the telephone Connections Museum of Seattle features an amazing piece of electro-mechanical technology from the 1950s — the 5XB trouble recorder. Museum volunteer Sarah the “Switch Witch” has a deep passion for old phone equipment, and gives an excellent description of the trouble recorder, the problems it solved, and how it works, and how they went about fixing it.

As central office switching became more complex and more dense, the manual methods of hunting down faults became unmanageable. Semi-automatic approaches using trouble lamps, but even that had its limits. This “stack trace”, which could have hundreds of indicators, had to be frozen while the technician recorded the status on a form. If another fault came along during this time, it was lost. The solution, using the available technology of the day, was a mind-boggling punched card apparatus that punches over a thousand bits of information when an switching error is detected or when various watchdog timers expire.

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Two landline phones connected to a set of wires and boards

How To Build Your Own Analog Phone Network

Analog phones may be nearly obsolete today, but having served humanity for well over a century they’re quite likely to pop up in drawers or attics now and then. If you’ve got a few of them lying around and you think it’d be cool to hook them up and make your own local telephone system, check out [Gadget Reboot]’s latest work. His video series shows all the steps towards making a fully-functional wired phone system.

Of course, dedicated phone exchanges for home or small business use are not hard to find, but [Gadget Reboot] decided it would be way more interesting to design his own system from the ground up. To begin with, he used off-the-shelf subscriber line interface circuits (SLICs) to implement the correct voltages, currents and impedances to drive analog phones. He then added a DTMF decoder chip to allow the phone to dial a number, and hooked up both systems to an ESP8266 which controls the entire system. It implements the different states of picking up, dialing, ringing and hanging up, and also generates the corresponding audio signals.

The system becomes even more interesting through the implementation of a multi-exchange layout, just like in large-scale phone systems: when a number is dialled that’s connected to a different exchange, then a connection must be made between two exchanges in order to complete the call. Large-scale systems use dedicated protocols like SS7, but [Gadget Reboot] preferred to keep things simple and used an RS-485 connection. The two ESPs check each others status and if everything’s in order, a relay connects the two lines and the circuit is completed.

The current system is a bit of a mess of wires, but it works, and [Gadget Reboot] plans to make a cleaner setup based on custom circuit boards, possibly expanding it with functions like modem support. In any case it’s already way more advanced than a simple electromechanical system. Want to know more about classic phone networks? We’ve got you covered.

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