Monday, January 31, 2011

Epad 10.2 review

Hi there!
it's time to review my newest gadget: the Android Epad 10.2"

As the name says, it is a iPad-clone with a slightly bigger screen (10.2") and running Android 2.1.
Here is a image of how it looks like in the commercial:

And here is another image of it, take with my digital camera: 

It is pretty hard to get it on camera, but this is, how the home screen looks like.
The Epad has a 1GHz ARM processor like the iPad, but it has a resistive touchscreen with 1024x600 pixels resolution, but unlike the iPad, it can be used with a pen or gloves.

 Here are some photos of the interfaces:

The internet connectivity is done via WiFi or an external USB surf stick.
It has two gigabytes of internal NAND flash and can use TransFlash aka µSD cards.
The PC data connection is done with a mini-USB cable, here called OTG.
You can charge the internal LiIon accumulator by applying 9VDC to the DC-terminal or simply using the included charger.
I was surprised by the rather high audio quality of the 3.5 mm output, even though the internal speakers are crap.  
You can connect it to a LAN with the included adapter, which looks like this:


The operating system is Android 2.1.
I like it, being small and fast.
It loads almost every website, even though it can't do every kind of script.
You can use it to view videos on YouTube, to watch DVDs (even via an external USB DVD drive!) or blogging on BlogSpot, as I'm doing now.

The virtual keyboard is a bit hard to use (You have to leave your hand some milimeters above the touchscreen and pull down the fingers separately), but you can use an USB keyboard.
If you want to exchange data without using a mini-USB cable, just do it using a µSD card. 

Some applications some exist in the Android Market, some you have to code on your own.
But hey, the Android SDK is free, so ain't it a great platform for mobile hacking?
I just need a compiler that runs directly on it.

You can pick these tablets up on ebay for about 200€ for a brand-new one or find it for the same price in other internet stores.
Finally, I would say, it's really a great gadget with much functionality for low price.

 I hope you liked this review!

Sunday, January 23, 2011

AVRTimerCalculator - JAVA-version

Here comes the requested JAVA-version of the AVRTimerCalculator.

You can download it here.
Share and enjoy ;-)

Thursday, January 20, 2011


This time it's a small piece of software, I've written to simplify the programming of timers in an AVR.
Many people, especially beginners or people who come from the Arduino corner dislike the timers due to their complexity. But it's really not that hard.
With a scientific calculator and a sheet of paper, you can easily set them.
And now I wrote this program, which replaces calculator and paper!
It looks like this:

It was written in VisualBasic, even though I like C# better.
I used VisualBasicExpressEdition to design the form.
You can download the source code and compiled program here.

Wednesday, January 19, 2011

My first self-programmed computer games

Here is a small, but fine compilation of my first self programmed computer games.
All of them are done in Visual Basic .NET.
I was 12 years old when I did them!

1. Hübbie Shooter
A small, but for a first game quite good game.
All you have to do is to "shoot" the flying birds with your mouse.
It uses about 50 different PictureBoxes which are made visible and invisible by a timer. Sorry, but this game is just available in German.
Here is a screenshot:

Download it here: 

2. Go!
Go is a Space Invaders clone.
You are the blue box and must shoot the red box.
Left shift is the "laser cannon" and left ctrl is the "guided missile".
This was my first game that used a non static surface.
It might not look so nice as Hübbie Shooter, but its much more fun!

Download here:

Well, this was my short trip to my oldest self-programmed computer games.
Hope you enjoyed it!

Thursday, January 13, 2011

Soft blinker with a NE555

And again a circuit with my favourite IC: the NE555!
Here is my version of the soft blinker:
You see right, there is no preresistor for the LED, due to the extremly high base resistor of the transistor!
Here is how much current flows through the LED:
    The current is between 2 and 5 milliamps, so you could also connect an npn-transistor to drive whole arrays with it.
It is not a sine wave, but a sawtooth.
But hey, it's a soft blinker with a NE555!
Here is a video I took of my prototype.


Friday, January 7, 2011

Full adder with relays

While playing around with 150 relays, I built a full adder.
I managed to get it down to 9 relays (closing type) and some diodes.
Here is the schematic:

Please note that relay 6 is just a drawing error, due to the diode near the closer of relay 8 it's unnecessary.
The Resistors are all 1k, which seems to be an appropriate value for my 24V/2.7kOhms relays, but maybe you need to change it depending on your relays.
The diode near the sum output might be useless, but I need more time to test it.
This all is not tested yet, it's just an idea I wanted to share.


Wednesday, January 5, 2011

Piezo problems

In my piezo fluid analyzer,
I used the piezo-stripe uncoated.
It seems like a small layer of metal is peeled off by the ultrasonic vibrations.
After half an hour in cream soap, a brown isolating layer had been exposed.
I think I'll try a thin coating around the piezo stripe.


Sunday, January 2, 2011

NE555-based fluid analyzer

Here comes my newest experiment:
A NE555 based analyzer for fluids.
It's basic task is to differ between different types of fluids like water, cream soap and so on based on their viscosity.
The basic idea is the following:
I encapsulate some liquid in a box with some kind of slider like this:
If I move the Slider like this

the fluid would move like that:

So if I use a constant velocity to move the slider,
I'll have to use a differing force based on the friction, which is defined by the viscosity.

Now my idea was to use a piezo stripe and a constant frequency.
The piezo would be the slider and the constant frequency would have the effect of a constant velocity.

Gone through all this, I built a small circuit with the NE555, a piezo stripe which I cut from a piezo speaker and a plastic box.
Here is the schematic:

I used one multimeter to measure the current through the piezo and another one to measure the system voltage.
The voltage defines the strength that the slider moves with.
Here is some data:

Tested objectCurrent(5V)Current(10V)
Cream Soap10mA30mA
All aquired at 19°C room temperature. with a 1.8 x 4 cm piezo stripe.

You can see easily the differences in viscosity between the fluid.
Ethanol has a rather high viscosity, so it takes little strength to move the slider.
Cream Soap is - like the name says - a cream and has a rather low viscosity.

How could I use this thing?
Well, in this configuration, it can differ between cream soap and water.
It's not everything, but hey, a proof of concept.
If you calibrate it and build a mechanical more stable version, you could use it to make automatic quality controls on your cream soap or such.
You could build one in SMT into a glass to measure if it contains beer or cola (or cream soap ;-).
Let's see what future will give us...


Saturday, January 1, 2011

Physics experiments

Hi and a happy new year.
My blog 2.0 goes into the new year with some experiments.
It's nice and calm in the time between the years, so don't expect big thing.
I'll rather do some experimenting with some physic things like densitiy, light spectrums, ...
The first thing will be the viscosity analyzer.

Well, then a happy new year!