What to do with a broken tablet

I was given a “no name” (Chinese) 10″ #Android tablet to figure out how to recuperate some pictures trapped inside and, if I wish, to keep it or to throw it. The kid of the owner drop it and the screen was broken, so no more usable. That I sought.

The micro SD being removed, by the owner, I guessed the pictures weren’t there.

What can I do to solve the puzzle?

First step: the only mean to send out an image was the HDMI port, so I bought a “mini-HDMI to normal-HDMI” cable from eBay and wait three weeks for it. With this cable, I was able to see that the tablet was still usable, in the sense of the initial demand. The touchscreen was still there and functional, only the LCD screen was broken.

I had some pain to figure out how to manage the touch screen, looking at the TV, where I connected the tablet with the HDMI cable.

With some more pain, I installed a free app to transfer the pictures over WiFi to my computer.

The job was done!

Now, what to do with a broken tablet?

The second step: the difficulty of managing the tablet through the touch screen, looking at TV, was too frustrating, so I wait for another three weeks to get a Bluetooth mini keyboard (the same dimensions as an iPhone) from eBay, of course.

The third step: reset the tablet to the factory settings and hooked it to my Google account.

The fourth and final step, for now: to install some free app (IP Webcam) and transform the tablet into a web-server with a webcam.

If you want to see it at work: here. But hurry, because I intend to put it to do some other things and it will not be anymore hooked to the Internet.


Radiation detection, Arduino and IoT (3)

The last version of this post is here.

The text bellow is obsolete and stays here only for historical purposes.


The third post, concerning this subject, consists only of a description of php script.

It does what it is supposed to do but I am convinced that there is a better (and elegant) solution to complete the task.

I choose to use an independent php script (that means that it runs by a command line and not under the web server control) similarly with a pearl or shell script

In fact it is a combination of two different php scripts because I need to sent data to two IoT platforms and, for this reason, I actually use two different methods stuck together in one script (no classes).

I am not happy with that solution so I made to myself the promise to change that code.

Here is that code. Continue reading

Radiation detection, Arduino and IoT (2)

The detection of radiation gives the need to measure it. Radiation detection yields pulses that are counted during a certain time (by minute, by hour, etc…). The amount found is converted in uSv/h (micro Sievert per hour).

Because I didn’t want to use a full Arduino, only to have counted the pulses sent by radiation detector, I actually use an Atmel ATtiny 45V controller that is doing very well in the role of Arduino. The main tasks of ATtiny so is to count the pulses sent by radiation detector during 10 seconds time period and send the value, by serial port, to the Big Brother (no, no, not That Big Brother!!!). This is my server that collects data around the house, keeps an eye on some places, listens and speaks over the Internet and so on… For this particular purpose there runs a script, written in php, that does the rest of the chores: calculates the radiation dose (represented in uSv/h from the value of  CPM – counts per minute – sent by ATtiny), saves the data locally on a file – together with the time-stamp -, sends it to the Cloud (Internet-of-Things platforms) where is visible (until now) on Exosite and Thingspeak.

To convince an ATtiny to play Arduino is possible as it is described in the arduino-tiny project, on Google-code.

Here are the schematics (ATtiny45 controller, RS232 adapter, Inter-connection cable).

The Arduino code for this job is here.

[To be continued]

Tiny power supply

I see a lot of examples of electronic experiments, mainly with low power devices, powered by batteries. If this could be a handy and smart solution for experiments and/or wireless/remote applications, it might not be  so desirable for all the others. Also could be a pricey one, sometime.

I always use a desk power supply, with enough resources (adjustable from 0 V to 40 V and current 0 A to 10 A), but sometimes I feel better with some other approach with a smaller footprint 😉 – my desk (work table) is so tiny…

My solution is a shortcut between a desk (bench) power supply and an dedicated one. During the last months I had the occasion to play with some nice pieces of electronic named PTN78060WAS, a pretty cryptic name, doesn’t it? That is, according to data sheet, a “high-efficiency, step-down integrated switching regulator”. It is made by Texas Instruments.

The coin is 1 eurocent and is a little smaller than an 1 US cent, in diameter and not in value 😉

Because there are two voltages, generally used with the current low power devices, 3.3V and 5V, I choose to build my tiny power supply with these two values. The standard application is shown on the first page of the data sheet and comprise a required resistor to set the output value of voltage. There is a table, on page 11, with Output Voltage Set-Point Resistor Values, therefore  for 3.3V  Rset = 79.3 kΩ and for 5.0V Rset = 21.0 kΩ. The final schematic is the same with these values:

Ci = 10 microF, ceramic (not polarized)

Co = 100 microF, polarized

Rset = 79.3 kΩ (for 3.3V) and 21.0 kΩ (for 5.0V)

Could be a little hard to find these exact values for Rset but the old trick with serial and parallel connection might give you a hand to figure out some closer values. Or you can use two potentiometers: 100 kΩ and 50 kΩ.

The upper is 3.3V and the lower is 5V


Radiation detection, Arduino and IoT (1)

These days is better to keep an eye on what happens around you. Not only economics, politics or weather changing but also radiation level. That is the goal for this post.

As my techno credo tells, to use, each time, whatever I have on hand and buy only when there is no other solution, as so I did here.

When the Fukushima  earthquake has brought, again, to world’s attention the radiations danger, the Internet was invaded by diggers for radiation stuff: the phenomenon, the detection, protection… A chilling recall of fifties and sixties when the danger was more political than this one: a combination of man-made and natural.

I found myself doing something, with more success than back in 1986, when, right after Chernobyl catastrophe, I did the same: looking for a radiation detector and I found it, eventually, with no Internet!

What I use now is an old and reliable Russian Geiger-Muller SI3BG buy-able on eBay (or other place). Looking around for stuff to match the intended application I found a dust gathering fancy light made for cars (you know, to put under the car to make it looking like a flying sauser, or so…). Inside of it is a dc-dc converter, from 12V to some high voltage, around 800V, necessary to power the glowing lamp. Applying  5V (not 12V) I was just obtaining 400V, the necessary voltage for my detector. Here is this schematic, with no details of what is inside of dc-dc converter but, out there, is plenty of this kind of schematics, on the Net.

Now comes the right moment to reveal the purpose of this project (it is almost clear from title, doesn’t it?): to be able to measure the radiation level at my venue (for the beginning indoor, during tests, and, eventually, outdoor) and to monitor it, by connecting the device to one, or another, of many  Internet-of-Things data platforms.

On Exosite  and Thingspeak you can see what the data is looking like. B.t.w. if you see nothing or it asks you to log-in, that translates as “Right now this is not public”.

[To be continued…]