Would you add another radio to your smartphone? No, not another WiFi or cellular radio; a smartphone already has that. I’m talking about something that provides connectivity through ISM bands, either 433 or 915 MHz. This can be used where you don’t have cell phone coverage, and it has a longer range than WiFi. This is the idea behind Skrypt, a messaging system that allows you to send off-the-grid messages.
Skrypt is an ESP32-based hardware modem that can communicate with a smartphone, or any other device for that matter, over Bluetooth or USB. Inside, there are two modules, an ESP32 WROOM module that provides the Bluetooth, WiFi, USB connectivity, and all of the important software configuration and web-based GUI. The LoRa module is the ubiquitous RFM95W that’s ready to drop into any circuit. Other than that, the entire circuit is just a battery and some power management ICs.
While LoRa is certinaly not the protocol you would use for forwarding pics up to Instagram, it is a remarkable protocol for short messages carried over a long range. That’s exactly what you want when you’re out of range of cell phone towers — those pics can wait, but you might really want to send a few words to your friends. That’s invaluable, and LoRa makes a lot of sense in that case.
5G is gearing up to be the most extensive implementation of mesh networking ever, and that could mean antennas will not need to broadcast for miles, just far enough to reach some devices. That unsightly cell infrastructure stuck on water towers and church steeples could soon be hidden under low-profile hunks of metal we are already used to seeing; manhole covers. This makes sense because 5G’s millimeter radio waves are more or less line-of-sight, and cell users probably wouldn’t want to lose connectivity every time they walk behind a building.
At the moment, Vodafone in the UK is testing similar 4G antennas and reaching 195 megabits/sec download speeds. Each antenna covers a 200-meter radius and uses a fiber network because, courtesy of existing underground infrastructure. There is some signal loss from transmitting and receiving beneath a slab of metal, but that will be taken into account when designing the network. The inevitable shift to 5G will then be a relatively straightforward matter of lifting the old antennas out and laying the new hardware inside, requiring only a worker and a van instead of a construction crew.
We want to help you find all the hidden cell phone antennas and pick your own cell module.
Via IEEE Spectrum.
With the latest and greatest 5G cellular networks right around the corner, it can be difficult to believe that it wasn’t so long ago that cell phones relied on analog networks. They aren’t used anymore, but it might only take a visit to a swap meet or flea market to get your hands on some of this vintage hardware. Of course these phones of a bygone era aren’t just impractical due to their monstrous size compared to modern gear, but because analog cell networks have long since gone the way of the floppy disk.
But thanks to the efforts of [Andreas Eversberg] those antique cell phones may live again, even if it’s only within the radius of your local hackerspace. His software allows the user to create a functioning analog base station for several retro phone networks used in Europe and the United States, such as AMPS, TACS, NMT, Radiocom, and C450. You can go the old school route and do it with sound cards and physical radios, or you can fully embrace the 21st century and do it all through a Software Defined Radio (SDR); in either event, calls to the base station and even between multiple mobile devices is possible with relatively inexpensive hardware.
[Andreas] has put together exceptional documentation for this project, which starts with a walk through on how you can setup your DIY cell “tower” with traditional radios. He explains that amateur radios are a viable option for most of the frequencies used, and that he had early success with modifying second-hand taxi radios. He even mentions that the popular BaoFeng handheld radios can be used in a pinch, though not all the protocols will work due to distortion in the radio.
If you want to take the easy way out, [Andreas] also explains how to replace the radios with a single SDR device. This greatly simplifies the installation, and turns a whole bench full of radios and wires into something you can carry around in your pack if you were so inclined. His software has specific options to use the LimeSDR and LimeSDR-Mini, but you should be able to use other devices with a bit of experimentation.
We’ve previously reviewed the LimeSDR-Mini hardware, as well as covered its use in setting up DIY GSM networks.
We’ve probably all got at least one old cell phone lurking somewhere around our bench. In most cases they’ll still work, but their batteries may be exhausted and their OS could be an ancient version. But sometimes there will be a phone that just died. One minute the flagship model, the next a useless slab of plastic and glass with the added annoyance of those priceless photos of Aunty May’s 80th forever locked in its memory.
[Andras Kabai] had just such a device land on his desk, a high-end Sony whose screen had gone blank. Others had tried, he was the last hope for the data it contained. He zoomed in on the eMMC chip on its motherboard, desoldered it and hooked it up via a specialist eMMC reader to recover those files. That was a very simple description of a far more involved process that he sets out in his post about it, a post that is fascinating reading and serves as a handy primer for any reader who might like to try it for themselves. We learn about the MMC interface and how simple it can be in its serial form, how with some fine soldering you can use a cheap USB reader, and that eMMC chips have a pinout conforming to a JEDEC standard.
Finally we see the software side as he takes the various SQLite databases and extracts the data for the user. It shows, all is not necessarily lost, however dead a phone may be.
We’ve seen [Andras] before, using an old scanner in his PCB fab.
The modern smartphone has a variety of ways to interact with its user – the screen, the speakers, and of course, the vibration motor. But what if your phone could interact physically? It might be unnerving, but it could also be useful – and MobiLimb explores exactly this possibility.
Yes, that’s right – it’s a finger for your mobile phone. MobiLimb has five degrees of freedom, and is built using servomotors which allow both accurate movement as well as positional feedback into the device. Additionally, a touch-sensitive potentiometer is fitted, allowing the robofinger to respond to touch inputs.
The brains behind the show are provided by an Arduino Leonardo Pro Micro, and as is usual on such projects, the mechanical assembly is 3D printed – an excellent choice for producing small, complex parts. Just imagine the difficulty of trying to produce robotic fingers with classic machine tools!
The project video shows many different possibilities for using the MobiLimb – from use as a basic notification device, to allowing the smartphone to crawl along a table. We frankly can’t wait until there’s a fully-functional scorpion chassis to drop an iPhone into – the sky really is the limit here.
Interested in other unique ways to interact with your smartphone? Check out these nifty 3D printed physical buttons.
With mobile phones now ubiquitous for the masses in much of the world for over two decades, something a lot of readers will be familiar with is a drawer full of their past devices. Alongside the older smartphone you’ll have a couple of feature phones, and probably at the bottom a Nokia candybar or a Motorola flip phone. There have been various attempts over the years to make use of the computing power the more recent ones contain through using their smartphone operating systems, but the older devices remain relatively useless.
[Vishwasnavada] has a neat plan though, using an ancient phone as a remote trigger device, by interfacing it with an Arduino. There are many ways this could be achieved depending on the model of the phone in question, but one thing common to nearly all devices is a vibration motor. Removing the motor and taking its power line to a GPIO allows the Arduino to sense when the phone is ringing. The idea then is that a call can be placed to the phone which is not picked up, but because it triggers the vibration motor it can be used to make the microcontroller do something remotely. A hack with limited capabilities then, but one that is cheap and simple, uses a recycled device, and should work almost anywhere populated on the planet given the global reach of 2G networks.
This isn’t the first respin of a classic Nokia we’ve brought you, they will also talk data.
For many of us, a calculator is something we run as an app on our mobile phones. Even the feature phones of a couple of decades ago bundled some form of calculator, so that particular task has joined the inevitable convergence of functions into the one device.
For [Scott Howie] though, a mobile phone is something to run as an app on his calculator. He’s integrated a cellphone module into his TI-84 calculator, and though perhaps it won’t be knocking Apple or Samsung off their pedestals just yet, it’s fully functional and both makes and receives calls.
To perform this feat he’s taken the cellphone module and one of the tiniest of Arduino boards, and fitted them in the space beneath the TI-84’s keyboard by removing as much extraneous plastic as he could. The calculator’s 4 AAA cells could not supply enough power on their own, so he’s supplemented them with a couple more, and replaced the alkaline cells with rechargeables. A concealed switch allows the cellphone to be turned off to preserve battery life.
The calculator talks to the Arduino via a slightly unsightly external serial cable, and all his software is handily available in a GitHub repository. His video showing the whole build in detail is below the break, so if you fancy a calculator with cellular connectivity, here’s your opportunity. Hang on — couldn’t you use a device like this for exam cheating?
Continue reading “A Calculator With 3G Inside”