Smartphone Bench Instrument Apps: Disappointment Or Delight?

November 17, 2016 by Jenny List 24 Comments

If you are interested in electronics or engineering, you’ll have noticed a host of useful-sounding apps to help you in your design and build work. There are calculators, design aids, and somewhat intriguingly, apps that claim to offer an entire instrument on your phone. A few of them are produced to support external third-party USB instrument peripherals, but most of them claim to offer the functionality using just the hardware within the phone. Why buy an expensive oscilloscope, spectrum analyzer, or signal generator, when you can simply download one for free?

Those who celebrate Christmas somewhere with a British tradition are familiar with Christmas crackers and the oft-disappointing novelties they contain. Non-Brits are no doubt lost at this point… the crackers in question are a cardboard tube wrapped in shiny paper drawn tight over each end of it. The idea is that two people pull on the ends of the paper, and when it comes apart out drops a toy or novelty. It’s something like the prize in a Cracker Jack Box.

Engineering-oriented apps follow this cycle of hope and disappointment. But there are occasional exceptions. Let’s tour some of the good and the bad together, shall we?

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An SDR For The Rest Of Them

November 15, 2016 by Jenny List 42 Comments

If you are a radio enthusiast it is very likely that you will own at least one software defined radio. With the entry point into the world of SDRs starting with the ultra-cheap RTL2382 based USB receiver sticks originally designed for digital TV, it’s a technology that passed long ago into the impulse purchase bracket.

If you are not a radio enthusiast, or not even a Hackaday reader, you may not have heard of SDR technology. Even the humblest up-to-date radio or TV may well contain it somewhere within its silicon, but at the user interface it will still resemble the device you would have had in the 1950s: analogue tuning, or a channel-flipper.

It is interesting to see an attempt to market a consumer device that is unashamedly an SDR, indeed that is its unique selling point. The Titus II SDR bills itself as the “World’s First Consumer Ready SDR Package”, and is based around an Android tablet mated with a 100 kHz to 2 GHz SDR tuner and a pair of speakers in a portable radio styled case. It will support all modes including digital broadcasting through software plugins, and there will be an open plugin API for developers. They are taking pre-orders, and claim that the launch price will be under $100.

It sounds like an exciting product, after all who wouldn’t want a radio with those capabilities at that price! However it leaves us wondering whether the price point is just a little too ambitious for the hardware in question, and we’ll reluctantly say we’ll believe it when we see real devices on the market. A $100 consumer price doesn’t get you much in the tablet world, and that is from high-volume Chinese manufacturing without the extra cost of the SDR hardware and the overhead of smaller volume from a niche product. There are pictures online of real prototypes at trade shows, but we’d like to see a website with fewer renders and more hard plastic.

There is another angle to this device that might interest Hackaday readers though. It should remind anyone that building one yourself is hardly a difficult task. Take an RTL2382 stick with or without the HF modification, plug it into a tablet with an OTG cable, install an app like SDR Touch, and away you go. 3D print your own case and speaker surrounds as you see fit, and post the result on hackaday.io.

Via the SWLing Post.

When Your Screen Breaks In The Himalayas

October 24, 2016 by Jenny List 26 Comments

If you’ve ever had the screen break on your laptop, you’ll know it can be rather annoying to have to use an external monitor for a while as you either wait for a replacement panel to arrive from the other side of the world, or wait for that new laptop you were just desperate for an excuse to upgrade to.

Spare a thought, then, for [tom bh] whose laptop screen broke while he was in Ladakh, Northern India. Two days bus ride from the nearest city in which he could hope to source a replacement part, he had to make do with the resources in front of him. A laptop with a broken screen, and his Android phone.

He was fortunate in that a few lines at the top of the screen still worked intermittently. So after logging in blind and finding himself in a shell, he could execute commands and then scroll the results up to the point at which they were visible. He first enabled an SSH server, then connected his phone via USB. A bit of work to find the laptop’s IP address, and he could get himself a laptop shell on his phone with an Android SSH client. He goes into detail about how he was able to use the laptop’s keyboard to emulate a Bluetooth device which he connected to the phone. He could then run a VNC server on the laptop and connect to it with a VNC client on the phone, resulting in a phone-sized laptop display using the laptop’s keyboard as input. Not a perfect physical terminal by any means, but enough for him to continue working.

His writeup is an especially interesting read for its side-by-side evaluation of the various different application choices he made, and contains some useful suggestions as to how anyone might prepare themselves for a dead screen related emergency.

We’ve featured a dead-screen laptop connected as a serial terminal with an Arduino in the past, but unlike this one that only gave its owner a prompt.

Via Hacker News.

Down The Rabbit Hole And Back Out Again: Serial Over Headphone Jack

October 21, 2016 by Elliot Williams 14 Comments

[ttsiodras] tells an epic tale of getting a custom Debian kernel installed on an Asus MemoPAD (ME103K) tablet. Skipping to the end of the saga, he discovers what looks like serial data coming out on the headphone jack when the system boots, but the signal was so distorted that he couldn’t simply interpret it. The solution turns out to be attaching a level-converter chip.

A level converter is a non-inverting amplifier, usually with a Schmitt trigger for immunity against noise. In this case, it acts like a “binarizer” — outputting a high voltage when the input rises above a threshold, and a low when it drops below. It’s the right part when you need to clean up a messy digital signal, and in this case works just fine because the capacitive distortion effects slow down both the leading and trailing edges of the signal, keeping the serial data’s timing intact.

That was the spoiler. If you want to read up on putting a custom Linux on an Android device, check out [ttsiodras]’s first post where he backs the machine up, and the second where he gets his custom kernel up and running. If you’re ever faced with an Android tablet that hasn’t been owned yet, or if you just have a DIY streak, this should help you get started.

Using the audio jack for serial is actually not uncommon, and discovering a serial terminal that listens at boot time is our favorite way to wedge a Linux OS into odd devices. So when you see a funny, distorted signal coming out at 115,200 baud, take a moment to clean its edges up and see what you’ve got.

Seeking Treachery In A Questionably Sourced Phone

September 26, 2016 by Mike Szczys 24 Comments

Have you ever considered sourcing an off-brand phone from the China markets? Why, or what stopped you? The answer is data and identity. You are trusting both when you decide to use a smartphone. Let’s face it, smartphones are a personality prosthesis in our society. They know your physical location, what your interests are, the people you hang out with, and how you spend your money. The keys to the castle are shared with these devices and you shouldn’t grant that kind of trust without knowing your phone is worthy of it.

But… what if that phone has amazing features at an equally amazing price? [ijsf] bought the phone and then made it earn the proper level of trust. The model in question is a Blackview BV6000s — pictured above in a tub of soapy water proving it’s IP68 claim. This thing has flagship specs but not a flagship name so [ijsf] took [Dave Jones’] advice and took it apart instead of turning it on. In this case, it is a complete ROM dump and disassembly.

The goals was to find malware — anything that is potentially leaking data. Nothing was found, which we think is because this phone isn’t nearly shady enough. We’d expect the bargain basement models (like this $3 ~~wonder~~ vaporware) to be more in line. That one actually has a carrier behind it which means they plan to recoup on usage charges. But suspiciously cheap phones may be using a business model that makes it back by stealing a chunk of your identity.

Two good things come out of [ijsf’s] writeup. First, it’s a decent guide to dumping and snooping in a ROM. Second, in addition to the fruitless search for thieving apps, the annoying bloatware was removed for a cleaner ‘stock’ image.

Pokemon Go GPS Cheat (If You Don’t Fear Getting Banned)

July 19, 2016 by Moritz Walter 75 Comments

Pokemon Go inherits a certain vulnerability to GPS location spoofing from it’s predecessor Ingress, but also the progress that has been made in spoof detection. Since taking advantage of a game’s underlying mechanisms is part of the winner’s game, why not hook up your smartphone to Xcode and see if you can beat Niantic this time? [Dave Conroy] shows you how to play back waypoints and activate your Pokemon Go warp drive.

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Fight That Tesla Envy With A Tablet Dash For Your Car

May 31, 2016 by Gerrit Coetzee 37 Comments

[Aykut Çelik] uses some strong words to describe how he feels about his VW Polo’s current radio set-up. Words like, “useless,” are bandied about. What is a modern man supposed to do with a car that doesn’t have built-in navigation or Bluetooth connectivity with phones? Listen to the radio? There are actual (mostly) self driving cars on the road now. No, [Aykut] moves forward, not backwards.

To fix this horrendous shortcoming in his car’s feature package, he set out to install a tablet in the dash. His blog write-up undersells the amount of work that went into the project, but the video after the break rectifies this misunderstanding. He begins by covering the back of a face-down Samsung tablet with a large sheet of plastic film. Next he lays a sheet of fiberglass over the tablet and paints it with epoxy until it has satisfactorily clung to the back of the casing. Afterwards comes quite a bit of work fitting an off-the-shelf panel display mount to the non-standard hardware. He eventually takes it to a local shop which does the final fitting on the contraption.

The electronics are a hodgepodge of needed parts: An amplifier, to replace the one that was attached to the useless husk of the prior radio set; a CAN shield for an Arduino, so that he could still use the steering wheel buttons; and a Bluetooth shield, so that the Arduino could talk to the tablet. Quite a bit of hacking happened, and the resulting software is on GitHub.

The final assembly went together well. While it’s no Tesla console. It does get over the air updates whenever he feels like writing them. [Aykut] moves forward with the times.

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