Marcin Barabasz

imagination is more important than knowledge… A. Einstein

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Useless box

When I saw it for the first time I knew I was going to build one myself.

Part list:

– Wooden box (I got it for 14 PLN in

– ON-ON Switch

– Servo (I used cheap Chinese servo from ebay – you can get one for as little as 2$ with free shipping)

– limit switch

– 2AA battery holder

– some wires

– PCB laminate

– Glue gun

– solder

I got electronic parts from local DIY shop for 5PLN total.

First thing is to reassemble the wooden box so that the hinges are on the other side (the box should open lengthwise instead of width wise). Then cut the lid so that both parts are separated. The lid should be cut with less angle so that it closes freely.

Next you need to do is to remove electronics from servo, and limiting pin as well if it exists. The end product should be servo with two wires connected straight to motor.

Next you need to wire things together. It is really not that hard – and nice exercise. The end goal is to have servo rotating in one direction until limit switch is pressed and when ON-ON switch is switched the servo should start turning in other direction that’s it really.

Actually the most tricky part is to attach servo to the box, and construct the arm so that it will open the box and turn the switch. After few failed prototypes made out of cardboard you should get it right. The final piece is made of PCB laminate.

At the end just attach the ON-ON switch to the box and your useless box is ready!

My working piece looks like this







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Cheap home surveillance camera

Very cheap way to implement home surveillance camera.

All you need is:

– old Android phone

– home wifi router (I assume this should already be in every apartament)

– access to some free DNS service (I use


Install application from Google Play

The configuration is very straight forward. Assuming your phone is configured to use your home WIFIyou should be able to access your streaming right away – just type on your computer the address (something like 192.168.1.xx:8080) and after selecting desired streaming technology you should see your stream. The next step would be to forward traffic from your router to your android phone:

Configure port forwarding on your router

There is a great page that will help you do that – I don’t want to write my own tutorial if something that great is available Just find your router brand and model and follow the steps. IP Webcam by default works on port 8080 so you need to forward your android phone ip port 8080 to some external port on your router like 8081 for example. The problem at this point is that you would need to know  your routers external IP address to access it from internet. Of course you could check the ip on one of the pages or better but that is typically changing (depending on your ISP of course). To get access to your router from internet you need to:

Configure your router to register on one of the free DNS services

This way you will be able to access your camera IP Webcam from anywhere. Here is good link that should get you started of course if you are using different router brand the configuration will be slightly different, but the principle should remain the same.

Assuming your domain will be something like “” your camera should be available under



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Kindle holder

This time something really small – but handy. It’s literally just 12×1 pvc pipe cut the way illustrated. It makes a perfect, very stable Kindle holder. There are two furrows, one with greater almost 90 degrees and one smaller angle. It is possible to put your Kindle in them both horizontally and vertically (the Kindle buttons are not pressed accidentally). It is very good to use this with kindle page turner 




Kindle remote page turner

Today I would like to write few words about a somewhat strange project I did. The need came from the fact that I was quite ill lying in bed for substantial amount of time with problems to move because of sores. I wanted to read something on my Kindle. I found it quite irritating to be forced to move my hand every minute or so to turn the page. I almost immediately thought, come on, there must be a smarter way to do it, and I came up with an idea of a remote page turner for kindle.

But how could that be done? One obvious choice is solenoids mounted on page switchers – but, hey, its the 21st century already. That would not be cool at all. So, the next choice is to hook up to the kindle’s usb port, but the problem is that the kindle works as a slave, not as a host – attaching any HID devices to its usb port is not really possible. USB is out of the picture. After searching the internet, I found that Kindle also has a serial interface. Unfortunately, it is not available unless you open it and solder the port yourself (even though I have done things like that in the past I certainly didn’t want to do it now) there has to be another way of approaching this problem. And finally I got it. WIFI 🙂 – Why didn’t I think of it in the beginning?

Ok, so WIFI, but how can I connect to my kindle using WIFI? Tt is the kindle that connects to the router. Maybe it would be possible to somehow connect (via ssh) to kindles IP address and send commands that way. That was the idea, but, as it turned out it wasn’t that straight forward after all – but doable! 🙂 after figuring out different bits and pieces I was able to ssh to my kindle from a pc great! That’s a big step. Sending commands that would imitate keystrokes should not be that hard since it’s all Linux under the hood. Few internet searches later I got the answer:

[root@kindle root]# echo "send 193" > /proc/keypad
[root@kindle root]# echo "send 191" > /proc/keypad

Et voila – those are the commands for turning pages forward and back respectively. I still I need a pc to connect to my kindle via ssh and send those commands. It doesn’t bring me any closer to the goal of being able to turn pages remotely, or at least without any large movements. The solution was to write an android app that does all that, and the actual remote would be a wired audio remote attached to my Samsung’s headhones. After maybe an hour of searching the internet, and another half hour of actual coding, I had an Android app in place and ready to operate. It is very rough and could probably be improved in almost every aspect, but it does its job perfectly. I can now lie in bed holding my wired remote between my fingers and read my kindle – isn’t that awesome?

There is still the possibility to go completely wireless with something like a bluetooth camera shutter, but I think that the first solution is good enough.

 P1200942 P1200940

Here you can see the assembled piece in action:

Android application code available there:


1. Jailbreak Kindle

2. Install USBNetwork update

3. Enable SSH over WIFI

4 Test out commands to turn pages via usb link

5. Write Android app to listen to remote commands and send commands to Kindles ssh server


ssh lib for java

kindle rooting and getting access to its ssh

UPDATE (17/08/2014):

Just few days ago I finally received my remote shutter for Android and iOS. It is a pretty cool device even if used for its original purpose. As stated in the previous post I was intending to at some point to “go completely wireless” and having remote shutter would make it possible. So here we go:

This is exactly how my device looks like. I bought it on ebay for just over 3$ with free shipping (it took almost one month to arrive but still it is a good deal).


After connecting device to my phone over bluetooth (which was dead easy, just pair devices) it was recognized as a bluetooth keyboard. I opened my camera app and it worked straight away I was able to take pictures with it (small android buttoe n). Of course I was curious about the bigger button, it would be cool to use it as FORWARD in this project where as the small one would fit for PREVIOUS perfectly. When pressed in home screen it is putting volume up – brilliant.

After quick modification of Android app I wrote, changing the keys that should turn the pages and adding possibility to modify kindle’s ip, kindle’s username, and kindle’s password. I was good to go for a first test. It worked!

As for the usage – it works pretty much perfectly, it is quick and reliable. The range is sufficient as you still need to see the Kindle, so1m is more than enough (I haven’t tested it but it should do at least 5m). There is one remark I need to make thou: The shutter turns itself to power preservation mode after around one minute from last usage – this means you need to read at least one page per minute to keep it up, which shouldn’t be a problem for a typical person. Pressing the button after that time takes around 3s to reconnect and then turns the page, I think it is acceptable.

The modified code can be found in github. At some point I am planning to put it to Google Play (even got developers account for that purpose), I am a little concerned thou since getting this setup to work requires few extra steps and some basic understanding. Stay tuned.

Wireless version in action: