Minor Android Update Tonight

My Samsung Galaxy S6 smart-phone runs Android 7.0, and received a minor system update tonight, which only required that 18MB of software be downloaded. The update completed quickly, but it will require some more, extensive use, before I can know whether the promised stability and security improvements are apparent.

I was never really dissatisfied with the phone’s stability.

Dirk

 

I have just received my NFC Tags.

In This Posting, I wrote that I had ordered NFC Tags from a seller in Australia, just to assure the maximum compatibility with the Android Apps named “NFC Tools” and “NFC Tasks”. Also, this exact brand of Tags (“Whiztags”) seems to have a high number of bytes stored, as far as domestically-used Tags go.

Just as a recap, I should say that Tags can store a small amount of data, which can be read by our device as we use the NFC scanning capability that must first exist in hardware. And this can be similar to how QR Codes can be used. Even though NFC Tags can easily store a small message, in practice we are more likely to store a URL, which when read back in, causes content to display which is visible openly on the Internet. Or, we can also store commands, which our own devices are supposed to carry out, when we tap our device on the Tag.

In the latter case, which I was hoping to start using eventually, it is important that the App which carries out the stored commands, in my case NFC Tasks, be 100% compatible with the App that was used to store those, in my case NFC Tools, as there is no worldwide standard for how commands or automated sequences of tasks, are to be stored. URLs, obviously, at least conform to such a standard.

Well my Tags just arrived in the mail for me. Nobody said that the shipment from Australia was supposed to be extremely fast, and in fact I believe that having purchased these at an extremely good price, pretty much ruled out that they would get shipped to me fast as well.

So now I can start experimenting with programming physically existent Tags, hopefully in a way that will make my use of my phone more practical.

I have to admit though, that before my Tags arrived, I had already started using the App named “Tasker”, along with some of its plugins, to automate and accelerate certain uses I have for my phone, without requiring any NFC Tags per se. Tasker tasks can be triggered just by tapping on an icon, or in my case, when the phone detects that it is charging wirelessly, or when I plug in my headphones…

Yet, there is a limit to how many icons I would want to have taking up space on the limited screen-space of my phone, so that I could conceivably still fine-tune what I want to use the phone for, by preparing several actual Tags, to do what Tasker can also do more or less.

One severe limitation to using NFC Tags however, is the standard fact, that the phone must be unlocked, before the Tag is tapped, before tapping the Tag can cause our phones to do anything. This is just common sense to protect the users. For example, if our phone is set up to make a card payment, by way of NFC, we would also want to make sure that not just anybody can initiate such a financial transaction, without having to unlock a locked phone first.

Well these Tags, by way of the App I installed, can tell my phone to change its settings and do various things which could undermine my security, if I had not programmed them themselves. So just as with the electronic payment card, there needs to be some sort of safeguard in place.

The NFC Tasks App offers an additional safeguard, in that its user can choose to enforce a whitelist, of tags that are authorized to give commands. I intend to use the whitelist feature as well, just so that no hypothetical interloper slips in a tag which I would not have programmed myself…

 


 

Also, there is another observation which I should add. The way the use of these Tags is popularly described, we should tap them with our phones. This would suggest that the Tags, which have an adhesive back, should be attached to a hard surface of some kind, because directly from the seller, they come as soft, thin pieces of plastic, which should not even be bent. It would also imply, that an accelerometer in the phone detects a physical tap, to trigger some NFC-realted service to start scanning for the Tag, which has no internal power source of its own.

These tags have arrived with a key-chain pendant, as advertized, that can act as a semi-hard backing, should I in fact attach one of the tags to this key-chain. I have discovered that the key-chain ornament is itself a tag of equal capacity, which can be verified by just approaching it to the phone while the app is waiting to read tags. Its stats will be displayed just as those of the softer tags. Because of that, It would be a critical error to attach another tag to the key-chain. If one did so, this would superpose two tags, and possibly make both unusable.

But the description of having to tap an NFC-related object physically, has been in error in the past. When I use my phone to make a payment for example, I only need to hold the phone in the vicinity of the store card reader, not tap it.

I have not yet been convinced, that the accelerometer in my phone triggers its NFC coil in practice. It could just as easily be, that the vicinity of one of my Tags will trigger the phone, or else – that the phone might fail to trigger for some unknown reason. If the last thing happens, I will need to troubleshoot.

Dirk

(Edit : ) The “Whiztags” which I have received, store up to 924 Bytes each, in pages of 4 bytes, and were sold to me as “A package of 10, plus one bonus tag”. This essentially means that I received 11 tags for the price of 11, including the key-chain pendant. They are color-coded for easy recognition, and the one which I have just now programmed, received 120 Bytes worth of tasks from me, which are allocated as 30 pages.

The softer tags have a very thin 3M-labelled backing, which should be peeled off gently, even though the backing itself adheres strongly, to reveal a clean adhesive surface, with which they can be attached to a clean hard object.

The key-chain that was included in my deal, serves as a possible place to attach one tag in this way. (No! See above comment!)

As I suspected, a strong touching motion or impact between the tag and the phone is neither required nor desired. It is only preferable to know where the NFC coil is located on our phone, in order for the tag to be recognized and processed – within a fraction of a second. On a Samsung Galaxy S6 Phone, this sweet spot is in the middle, of the top half of the phone.

Once a tag approaches there, it is processed exactly as advertized – in my young experience. By now I have also learned: Sometimes, if an operation on a tag seems to be taking too long, the app is actually waiting for the detected tag to be distanced, which the user may still be holding to the device from a prior operation. And then, if the tag is approached anew, the requested operation only takes a fraction of a second again.

 

I am currently charging my phone wirelessly.

My phone is a “Samsung Galaxy S6″. It is not an ‘S6 Edge‘, nor an ‘S6 Edge+’. As the ‘S6′ goes, when it was first released onto the market, this phone was considered to be advanced, because it did not require a special cover for wireless charging, and because the built-in charging capability included compatibility with both the ‘Qi’ and the ‘PMA’ systems, which were maintained by independent companies.

Yet, by default I had been charging this phone with a USB cable and a special USB wall-power adapter, that lets the phone know via the data wires that it can draw 2A of charging current, instead of 500mA. Doing so always put wear and tear on the USB jack of the phone.

Starting a few days ago, I had bought myself a Qi wireless charging pad by the brand-name “JETech”, and I find that this charging pad does the job well. I was surprised to learn, that these charging pads no longer come with 110VAC cords to plug in, but that we connect the pad to its power source, via the 5VDC, 2A, USB power adapter.

Charging the phone from 50% all the way back up to 100% via Qi-wireless takes about 1 hour and 20 minutes time, which I think is impressive.

But there is a more recent development in this realm, that I should also mention. Starting with the ‘Note 5′ and the ‘Samsung Galaxy S6 Edge+’, and including the ‘S7′, Samsung has decided to produce its own type of wireless charging system, which is supposed to be even faster. In fact, when I first went to the store to request a charging pad for my S6, the tech person in charge automatically sold me a ‘Samsung Fast Charging Pad’, knowing the fast charging feature would only work with the Edge+, but nevertheless assuming that slower charging would still work with my S6.

As it turns out, the Samsung Fast Charger that I received did not work with my S6, even at standard charging speeds. This could be due to an incompatibility, or due to one defective unit sold to me. I rather suspect the former. The symptom was, that charging would seem to begin, but that after charging for about 1 second, charging would pause, and that 1 second after that, charging would start again – endlessly. And this would also happen eventually, after I had removed the phone from its case, which in my case is an “Otter Box”.

So I had to return the Samsung-brand Charger to the store, where I received a refund. And that was when I decided to buy the ‘JETech’.

The JETech actually does a better job on my S6 than the brand charger did, especially since in my case, the brand charger only produced an endless series of notifications, and accomplished no charging effect at all. And I can leave my phone in its Otter Box case, while charging successfully on the JETech pad.

If it becomes possible for my use of the JETech charging pad to replace my former use of the Micro-USB-port on the phone completely, doing so may also increase the overall usage period of the phone, since if it was ever to become impossible to charge, it would also become impossible to use…

Dirk

(Edit 03/23/2016 : ) I had observed that modern devices with USB charging have some mechanism by which to increase the charging speed from ‘Cable Charging’ to ‘Fast Charging’, which the notification will indicate. I also know that usually, the power source will define the voltage, while the load will decide to draw some amount of current. It all becomes difficult to manage, at low voltages and high current levels. But I had not known the exact details until today.

At least with Samsung, the way this works is as follows:

An “Adaptive Charger” is capable of delivering either 5VDC or 9VDC. At 5VDC, it can handle loads of up to 2A. At 9VDC, it can handle loads of up to 1.67A. The device to be fast-charged actually sends a signal to the charger, which triggers it to deliver 9VDC on the USB cable, instead of the usual 5VDC. At 9VDC, Fast Charging mode can commence.

One problem with fast-charging at 5V would have been, how impractically close this voltage is to that of the battery in the mobile device. A fully-charged Li-Ion battery has approximately 4.5V, which is only 1/2 Volt less than the standard USB voltage was.

Wires, connectors and control circuits all add series resistance to a circuit, and even if the series resistance was only 1/2Ω (Ohm), then at a theoretical current of 2A, the circuit would lose 1 Volt right there. This would put the voltage arriving at the battery at 4V, which is already lower than that of the battery nearly charged. And so it would have been an improbable – and destructive – feat to get the device actually to draw 2A when connected to the USB port of a computer.

The version of what happens which I now entertain, is that the USB port of a computer may have a ‘current-limiting transistor’, which limits the output current to 500mA actively, even if doing so only means inserting a resistance of 1Ω (Ohm), and thus inserting a voltage drop of 1/2V. It may be the case that when connected to a charging adapter capable of supporting 2A at 5V, the actual mobile device still achieved much less charging current than that.

Dirk