Nov 8, 2013

DIY MaKey MaKey

I was just browsing around the internet and came across this video which described how to make your own Makey Makey board using an Arduino Leonardo. I had all the components laying around at home so I decided to make my own. Here is a video where i used 4 glasses of water to play some drums from http://www.virtualdrumming.com/. No I can't play music, well not right now anyway :-).












The Makey makey is basically a circuit that converts anything conductive - even slightly conductive (Metal, Coins, Bananas, Humans, Coke Cans, Glass of Water, etc.) into a button on your keyboard. You connect a wire from the circuit to the object you want to make into a button (key). Connect your self to the wire from the circuit labeled "hand". Done. Now the moment you touch the object it will send a key-press (example 'a') to your computer via USB. 

Using the Arduino Leonardo you can convert up-to 6 objects into a key at any given time. Unfortunately i had only 4 crocodile clips at the time with me so I made only 4 keys. You could make 6 if you wanted to.

If you want to build your own check out the video it is quite well made and goes through the whole process step by step. The circuit is ridiculously simple. The way it works is it makes a potential divider circuit between the Resistance (on one side) and your body+object (on the other side) and reads the voltage from the center. Using this voltage it figures out if you have touched the object or not. Because the resistance value is huge (10 mega-ohm and more) even slightly conductive objects can be made into keys.


Red - Connects to the Arduino Board
Blue - Output - Connects to the objects and your hand.
Purple - Resistance (Use 22 Mega-ohm  if possible, I used 10 Mega-ohm)

Once you have made the circuit you can write the code to Arduino (Available in the description at http://www.youtube.com/watch?v=WDPTA0-fbNE).

In my case I modified an Anti-Static strap to use as a connection from the circuit to my hand because i did not want to hold a wire every-time i use the circuit.

Note for people that get scared (to my surprise there were quite a few of them - I don't blame them how should they know) of using this because it might give you a jolt : It is perfectly safe to use (well unless you go Full Retard and do something incredibly stupid like connect this to the mains power in your house.)

If you don't want to build your own version of this and just want to play around. Just order one from the makey makey site and have fun.

Update: Version 2.0 - Better case, A lot more modular.


Nov 7, 2013

Macro Shots with a Canon 600D

I recently bought a a Lens Reversal Ring  for my DSLR. It is a pretty nifty gadget available at dirt cheap prices. The way it works is you screw it on the filter thread of your lens and then mount the whole lens to your camera in a reverse orientation. What this essentially does is it converts your lens into a macro lens lens (You can focus on things that are super close to your lens).


Obviously there are some disadvantages to this approach rather than getting a proper macro lens. Firstly as your lens is mounted in reverse you don't have any control over the electronics (So auto-focus). Secondly, in case of canon lenses (in Nikon it closes down) the lens opens up the widest aperture (with no control) which can be a problem some times as you get a really shallow DOF which causes issues sometimes.



For the second issue there is a workaround and it works (well sort of - alteast on Canon 600D and other similar cameras). Lets say you want to click a pic with an aperture at f/7.1.

Step 1: You do is you put you camera in video mode. Your lens should be mounted normally as it usually is.



Step 2: Set the aperture as needed. In this case f/7.1



Step 3: Now without changing any setting and without turning you camera off remove the lens. The aperture will be stuck at whatever value you set in the video mode. Screw on the reversal ring and mount the lens in reverse.



I shall try to put up a tutorial video in a few days.

For focusing there is not much you can do. The focus ring is pretty much useless (especially if you have an STM lens). In the kit-lens the focus ring is okay but this can only be used for fine-tuning. Almost all the focusing has to be done by moving the lens around (Be careful as you are very close to the subject you might scratch you lens). You will in most cases need a tripod as even a tiny shake is very noticeable in macro shots.

Anyway here are my first few shots. If you need the settings (ISO, Shutter Speed etc) go to
photos.abhimanyukumar.in












Nov 3, 2013

Guitar 3D

I've been learning how to play the guitar for a few now days. As customary I had to render out a 3D image of one (not the exact guitar I'm learning on)

I downloaded the basic structure of a guitar form some site a few days back (I forgot the link from where). Anyways it was a simple low poly model so I had made a lot of changes to the same. Refined the whole thing. Did the texturing, lighting and camera setup.

After that rendered the whole thing out (took about 20 minutes for each image as 4K). The DOF was added later in Photoshop as rendering it out was too tedious.