A Tidy Clamshell Keyboard For The Pinephone

October 27, 2021 by Lewin Day 9 Comments

Something a lot of people don’t realise about modern smartphones is that many of them have fully-featured USB interfaces. Perhaps the best of all is the Pinephone, which is a fully open-source smartphone that gives end users total control over their phone experience. [silver] has such a phone, and set about building himself a neat keyboard setup for the platform.

The build is based around an RCA RKT773P tablet keyboard case, which uses USB to interface with a tablet via pogo pins. [silver] modified this by soldering on a USB cable to the pins, paired with a USB-C host adapter on the Pinephone. Paired with a few 3D printed parts to hold everything in place, it almost turns the assembly into a cute little Pinephone laptop.

It’s a neat build that would likely save a lot of frustration when hacking away at a terminal window on the Pinephone. Parts are available on Thingiverse for those interested in replicating the hack. Those eager to dive into the Pinephone platform may relish the new Pro model that has just dropped, too. Video after the break.

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A homebrew telephone connects home and workshop.

The Calls Are Coming From Inside The House (or Workshop)

October 19, 2021 by Kristina Panos 16 Comments

Hot on the heels of their carbon microphone build a few years ago, [Simplifier] strung up a two-phone network between the house and the workshop. Both telephones are completely DIY except for the pair of switches on the front. Each side has a bell, a microphone, and an audio transformer. Listening is done through a pair of headphones, and both users speak through a homebrew carbon microphone.

We particularly love the bell, which is made from fence post caps. Sitting between the bells and ready to strike is a ball bearing mounted on a really thick piece of wire that’s driven by an electromagnet. To make a call, you use both switches — the one on the left pulls either the bell or the microphone to ground, while the switch on the ~~left~~ right is used momentarily to send 6 V from the lantern battery down the 50 ft. line to the other phone to ring it. You’ll see what we mean in the demo video after the break. Check out the sound of those fence post caps!

[Simplifier] wound an audio transformer that provides the necessary impedance matching to use regular headphones as receivers. Since the homebrew microphones only need 1.5 V, [Simplifier] split the voltage across two carbon contacts placed in series. That’s still more than necessary, but [Simplifier] was able to make it work.

More recently, [Simplifier] has built a beautiful and even better carbon microphone and even hosted a back-to-basics Hack Chat.

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Showdown Time For Non-Standard Chargers In Europe

October 12, 2021 by Jenny List 115 Comments

It seems that few features of a consumer electronic product will generate as much rancour as a mobile phone charger socket. For those of us with Android phones, the world has slowly been moving over the last few years from micro-USB to USB-C, while iPhone users regard their Lightning connector as the ultimate in connectivity. Get a set of different phone owners together and this can become a full-on feud, as micro-USB owners complain that nobody has a handy charging cable any more, USB-C owners become smug bores, and Apple owners do what they’ve always done and pretend that Steve Jobs invented USB. Throwing a flaming torch into this incendiary mix is the European Union, which is proposing to mandate the use of USB-C on all phones sold in its 27 member nations with the aim of reducing considerably the quantity of e-waste generated.

Minor annoyances over having to carry an extra micro-USB cable for an oddball device aside, we can’t find any reason not to applaud this move, because USB-C is a connector born of several decades of USB evolution and brings with it not only the reversible plug but also the enhanced power delivery standards that enable fast charging no matter whose USB-PD charger you are using. Mandating USB-C will put an end to needlessly overpriced proprietary cables, and bring eventual unity to a fractured world. Continue reading “Showdown Time For Non-Standard Chargers In Europe” →

Dial A For Arduino

October 9, 2021 by Al Williams 19 Comments

A lot of phrases surrounding phones don’t make sense anymore. With a modern cellphone, you don’t really “hang up” and there’s certainly no “dial” to be had. However, with [jakeofalltrades’] project, you can read an old-fashioned phone dial using an Arduino.

The idea behind a phone dial is actually pretty simple. When you pull the dial back to the stop using one of the numbered holes and release it, it causes a switch to open and close the same number of times as the hole you selected. That is, if you pull back the 5 hole, you should get 5 switch closures. The duration of each switch event and the time between switch events is a function of the speed the dial moves because of its internal spring. The zero hole actually produces ten pulses.

There are standards for how precise the timing has to be, but — honestly — it’s pretty loose since these were not made to be read by precise microcontroller timers. In the United States, for example, the dial was supposed to produce between 9.5 and 10.5 pulses per second, but the equipment on the other end would tolerate anything from 8 to 11.

Even if you don’t want a rotary dial in your next project, the code has some good examples of using ATmega328 timers that you might find useful in another context. However, a dial would add a nice retro touch to any numeric input you might happen to need.

If you need project inspiration, how about a volume control? Or, why not a numeric keypad?

Build Yourself A Nifty Cable Smartphone Mount

September 5, 2021 by Lewin Day 6 Comments

Smartphones have supplanted cameras in day to day use for the vast majority of purposes. However, unlike cameras, they don’t come with tripod mounts or any real good way of holding them in a set position. [Mrballeng] has built an excellent mount, however, that uses cable to hold a smartphone in all manner of positions, for photography or other purposes.

The mount relies on vinyl-coated steel cable. Upon this cable are slotted four blocks that are 3D printed out of resin. The blocks are also fitted with strong magnets. This allows them to be positioned along the vinyl cable while sticking themselves in place thanks to the magnetic attraction to the steel core. The blocks can also be used to attach the cable to magnetic objects like drywall screws or light fittings.

Using the mount is simple. The cable is wrapped around the phone and the blocks cinched up to hold it in place. Then, the magnets in the blocks can be used to hold the phone to walls or other surfaces.

It’s a tidy build, and one we can imagine using regularly if we had one. Of course, there’s no reason you couldn’t produce the parts on a more common filament-based printer, either. We’ve seen some other great smartphone photography hacks too, like this mod that lets you use your phone as a microscope for under $10. Video after the break.

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Pining For A De-Googled Smartphone

September 2, 2021 by Bryan Cockfield 89 Comments

Last summer in the first swings of the global pandemic, sitting at home finally able to tackle some of my electronics projects now that I wasn’t wasting three hours a day commuting to a cubicle farm, I found myself ordering a new smartphone. Not the latest Samsung or Apple offering with their boring, predictable UIs, though. This was the Linux-only PinePhone, which lacks the standard Android interface plastered over an otherwise deeply hidden Linux kernel.

As a bit of a digital privacy nut, the lack of Google software on this phone seemed intriguing as well, and although there were plenty of warnings that this was a phone still in its development stages it seemed like I might be able to overcome any obstacles and actually use the device for daily use. What followed, though, was a challenging year of poking, prodding, and tinkering before it got to the point where it can finally replace an average Android smartphone and its Google-based spyware with something that suits my privacy-centered requirements, even if I do admittedly have to sacrifice some functionality.

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Arduino Caller ID Display Is Better Late Than Never

August 20, 2021 by Tom Nardi 12 Comments

It’s no secret that the era of the landline telephone is slowly coming to a close. As of 2020, it was estimated that less than half the homes in America still subscribed to plain old telephone service (POTS). But of course, that still amounts to millions upon millions of subscribers that might get a kick out of this Arduino caller ID developed by [Dilshan Jayakody].

HT9032D caller ID decoder board — The completed HT9032D board.

Truth be told, until this point, we hadn’t really given a lot of thought to how the caller ID system works. But as [Dilshan] explains, you can actually pick up a dedicated IC that can decode incoming caller data that’s sent over the telephone line. In this case he’s using a Holtek HT9032D, which comes in a through-hole DIP-8 package and can be picked up for around $2 USD. The chip needs a handful of passives and a 3.58 MHz crystal to help it along on its quest, but beyond that, it’s really just a matter of reading the decoded data from its output pin.

To display the caller’s information, [Dilshan] is using an Arduino Uno and common 16×2 HD44780 LCD. As a nice touch, the code will even blink the Arduino’s onboard LED when you’ve missed a call. As a proof of concept there’s been no attempt to condense the hardware or ditch the breadboard, but it’s not hard to imagine that all the components could be packed into a nice 3D printed enclosure should you want something a bit more permanent.

We’ve seen caller ID data being collected in previous projects, but they used a USB modem combined with a software approach. We really like the idea of doing it with a cheap dedicated IC, though we’ll admit this demonstration would probably have been a bit more exciting a decade ago.

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