Apr 30, 2011

Quadrocopter - Part 5 - Paisa Ye Kaisa

 Here go a few updates on the quadcopter (CPUV) project. As mentioned in my previous post I will be using the Wii Motion Plus and  Wii Nunchuck for the IMU of the quadcopter to keep it stable.I ordered both of them recently from eBay and they just got delivered. Also i needed a micro-controller to manage the quadcopter's movements so i ordered an ATMEGA328 with an Arduino bootloader on it, again from eBay. I also ordered a spare battery , and a Hobby-King 6-Channel 2.4GHz FHSS Transmitter and Receiver from RCHobbyAddict.

I shall explain i detail all these component choices in detail once i get the quadcopter to fly and write a complete build log along with the schematics and components.

Now that i have purchased almost all the major components required for the quadcopter i just wanted to give the estimated cost of the entire project for someone looking to build one:

Brushless DC Motors - EMAX 282250542020
Brushless ESC - EMAX 18A88943556
Prop Savers614244
Propellers - 9x6E1121672
Adapter 12V 5A4501450
Li-Po Balance Charger221212212
Connectors(Bullet,Berg etc.)--250
RF - 2.4GHz FHSS 6Ch Tx & Rx325013250
LED Strips (RGBW) - 12 LEDs in Each1204480
ATMEGA328 - Arduino 3351335
Wii Motion Plus107511075
Wii Nunchuck 4901490
Lipo Battries 3S1P 2200mah 20C122522450
Small Electronics--200
Misc(Glue,Tape,Shipping etc.)--500

Total : 18,634

Links to part 1 ,part 2 ,part 3 & part 4

Apr 25, 2011


Here is the design of the automatic paintball gun that i'll be putting up on the quadcopter.

Apr 24, 2011

Quadrocopter - Part 4 - Spinning out of Control

In the previous post i mentioned that i needed gyroscopic sensors and accelerometers to stabilize the quadrocopter.For more detail on these sensors visit Gyroscope and Accelerometer. Basically what i'll be doing is using these sensors find out the orientation of the quadrocopter relative to the ground. With this data i can adjust the speed of the various motors (using something called as PID Controller) to stabilize the quadrocopter in a particular orientation. Now to move the quadrocopter in any direction you adjust the speed of any one (or all) the motors so as to get the proper direction of motion. For more info on how a quadrocopter actually flys go here.

There are two ways (that i have thought of) to obtain these sensors:
               1) Buy it off the self
               2) Salvage it from any commercially available product that already has these sensors (such as the PS3 Move, Nintendo Wii, iPod Touch, your new touchscreen phone,etc.

Both ways have their advantages and disadvantages.

Buying off the self makes it very easy to interface the sensors with any micro-controller but it is expensive when compared to the alternative.Salvaging it from a consumer device is tricky and requires a bit of hacking but is less expensive depending on what device you use.I decided to go for the second option.

Now i had four choices of devices:

  • My iPod Touch 1st Gen
  • My Phone (Samsung Wave S8500)
  • PS3 Move 
  • Nintendo Wii
I gave up on the iPod and the phone because they did not have a gyroscope sensor (kind of important) plus i did not want to seem them destroyed if CPUV crashes. So i decided to go with the PS3 Move or the Wii. I was leaning towards the Move as it also had a 3-Axis magnetometer but after some help form Kenn Sebesta (http://www.eissq.com/ps3_move/) i found out that i would need a programmer for the onboard STM32 chip to get it to work for the quadrocopter. I would have to write a custom firmware into the chip as the current firmware switches off the entire controller as soon as it goes out of Bluetooth range ( going to happen in my case). The programmer costs about $20 in the use but shipping it to India the price including shipping goes up over $60 which is a problem. For $60 (about Rs.3000) i could get myself a decent 6-Ch RF controller which is also necessary. 

So i decided to go with the Wii. I will use the gyros in the Wii Motion Plus and the accelerometers in the Wii Nunchuck for the project as of now. Working on the Move would have been awesome but sadly the cost involved is too high for something that i can do without. I will try to upgrade the quadrocopter later but as of now in sticking with the Wii.

Wii Motion Plus

Wii Controller + Nunchuck 

PS3 Move

Links to part 1 ,part 2 & part 3

Quadrocopter - Part 3 - Tied Down

First of all the name. I've decided to go with CPUV (or Chatur-Pankh-Udaan-Vastu). Thanks Anshuman for suggesting that name.

In the last post i mentioned that i was going to do a test flight and put up a video so here they are:

For the test we (me and my roommate mudit) initially decided to use a RF link to control the quadcopter but due to some technical difficulties (i.e laziness, unwillingness to work and a general lack of interest in actually doing so) we could not actually use that so we put a small program on an ATMEGA16 that initializes the motors and then gradually increases the speed of the motors till it reaches a maximum and then to minimum rather quickly and then repeats the process over and over again.

Now the quadrocopter does not have any gyros or accelerometers as of now to stabilize it (More in part 4) therefore i had to tie it down to a table or else it would have taken off, spun out of control and probably crashed.

Links to part 1 & part 2.

Apr 21, 2011

iPhone 4

Renders of iPhone 4 made in 3DS Max 2011 using mental ray textures. 

Apr 20, 2011

Quadrocopter - Part 2 - Lighting It Up

Ok i got a bit further with the qua, drocopter (link to part 1) project. I've finished the wiring for the motors and added a few LED's. I've also mounted the propellers and decided on the the design of the landing gear.

As far as the stuff still left to do the list goes as below:

  • Flight Computer
  • Gyros and Accelerometer for stabilization 
  • Radio Control
  • System software for monitoring telemetry
I'm hoping ill have everything done by the middle of may. Will upload all schematics and code then. After that i'll try to add some more gadgetry to the quadrocopter such as:
  • GPS
  • Automatic Paintball gun
  • Camera Mount with Pan-Tilt
As far as the Accelerometers and Gyros i was thinking of going for the sensors on either the Nintendo Wii Motion Plus or the Sony PS3 Move controllers because they are way cheaper than buying off the shelf parts and will involve some sort of hacking. Now my roommate is  also building a quadrocopter and he decided to use the Nintendo Wii so in the spirit of being different i am going for the PS3 Move. Also the move has a 3-axis magnetometer on it so thats always good. I still have to order the move controller and will probably be doing it in a day or two after a bit more research. If you want to read more about why we need these sensors please go here.

Now a few pictures of the updates to the quadrocopter:

The Quadrocopter - All wired up

The Propeller - I had to use binding wire to hold it in place as the rubber rings that came with the prop saver are really not safe and tend to break. 

The Power Conduit - Used to distribute power to the main motors and the LEDs. This one is the +VE terminal

Wiring - Red for +VE Black for -VE ... The thick wires are for the motors,The thin ones are for the LEDs and The yellow ones go to the battery.

3.5 mm Gold connector for connecting the Li-Po Battery

The LEDs go on - 48 in all - 12 Red 12 Blue 12 Green and 12 White

From the bottom

In the Dark

That just looks cool

Update: Conceptual Renders

Conceptual Render -1

Conceptual Render - 2

Conceptual Render - 3

Conceptual Render - 4

The motors are also wired up and i'll be doing a test on flying the quadrocopter tomorrow using my roommates flight computer and will post videos ASAP. One more thing i'm sick of calling it quadrocopter. Any suggestions for names ? 

Apr 18, 2011

Creating HDR Images using a normal (phone) camera

I was getting a bit annoyed trying to explain a few people (you know who you are) that the iPhone camera is not different from their phone cameras (also having a 5MP sensor) and that with just a bit of hard-work they can also get HDR pictures. All u need is an app that does that for you ...

Ok fine for all the people who do not want to install an app on their phone or want to create HDR using a normal "Digi-cam" there is another way. You can use Photoshop (or GIMP for you Open Source freaks) and make yourself a an HDR image.

The process is fairly simple but this post is just for the above mentioned people and for all the others who are oblivious to the fact that this can actually be done. So is what u need : 
            1) A camera that has adjustable exposure settings  
            2) Photoshop or GIMP (why did they have to name it that?)
            3) A tripod or a stand of some sort that you can put the camera on. (Not really necessary if you have very steady hands)

Now put the camera on the stand and click a bunch of pics of the scene from the same location but with each pic  vary the exposure. The first pic you take should have the least exposure. The next one should have a higher exposure and just keep on increasing till u reach the max exposure.The basic idea is for you to have the same image at different exposure levels.You need at-least 3 images with different exposures(low,normal,high) for this to work but the more you have the better the final output.

Here are the images i took using the camera on Samsung Wave S8500

 Exposure -2.0

 Exposure -1.5

 Exposure -1.0

 Exposure -0.5 

 Exposure 0.0

  Exposure 0.5

 Exposure 1.0 

 Exposure -1.5

  Exposure 2.0

For creating the final HDR output just do the following steps(Photoshop only):

File>Automate>Merge to HDR....

Now select all the files u need to be merged and click OK.... After that just adjust the image using the slider to your needs and done.... Save file as .hdr (32bit bpc).

An interesting thing to note here is that if your pics are a bit misaligned then Photoshop will correct it for you but it will take a longer time to calculate the result.

Here is my final output. I could not upload a .hdr file to picasa or flicker so i just took a screen shot of it and made it a .png file

If you are wondering that that looks exactly the same as some of the pics above then you are right and i shall explain why in another upcoming post because this needs a detailed explanation.

Also here is my tripod (well sort off). It is a piece of thermocol with a slit in it to keep my phone in.

If u need the find out what exactly is HDR go to Wikipedia or wait for me to write an article on it (I shall do it soon in another week or so).

Apr 2, 2011

Quadrocopter - Part 1 - Getting Started

The first time i heard about a quadrocopter was when i saw a video on how the special effects in spiderman 2 were done (the scene http://www.youtube.com/watch?v=_NLgY6f60CA at 1:45 was shot using a quadrocopter).I was amazed at the maneuverability of this machine.I wanted one but buying one was out of the question mainly because of the cost of a ready-made product. Also personally i would be happier if i built one instead of buying it.

So about about 2 weeks ago i though i would go ahead and build one. I still have no idea what i will do with it when i'm done but who cares. I ordered all the mechanical parts i would need (details later) , bought a drill  and got to work on fabricating the body of the quadrocopter. 

The design is fairly simple(as is the case with most quadrocopters). It is basically an X shaped system (built with aluminium rods, acrylic sheets and bolts) with a with a brushless motor connected to a propeller at each end. The electronics, batteries, and the "flight computer" (as my roommate calls it) go in the center of the X. 

Here are some pictures of my progress so far along with the details of the components used:

The entire quadrocopter will fit in a circle of 16" radius.

The center console. Size 6"X6"

The acrylic sheet used is 3mm thick.

Aluminum rods used are 3/4" thick.

The motors : CF2822 - Details

Motor Mount

Motor Fixed and all wired up

The Electronic Speed Controller (ESC) - 18A - Details

Propellers - 9x6E - Clockwise

Propeller mounted on the motor


Battery - 2300mah - 20C 11.1V

Battery Charger

All the components(motors,charges,batteries,ESC,propellers) i bought were from rcdhmaka India as they had the most competitive prices.The aluminium,acrylic sheet,bolts were bought from various shops locally.

Next phase would be to get the quadrocopter to fly but that will have to wait for a week or so as i have some animation work that i need to finish.I Hope to get it up and running by the end of the month.

I have brought all the electronics that will be required to control the system. The only thing that remain are the accelerometer and gyro sensors (will probably hack the Wii controller or the PS3 move to get them) and the RF control modules.I will do a bit of research before i order these component.

Also my roommate is also building one (actually to be fair it was his idea to start building it in the first place) so for detailed buildlogs you can visit his blog (http://muditsdiy.blogspot.com/). You can also send me a mail if u have any queries.

How to make an omelette using a power tool.

I am building a quadrocopter and was making the frame for it (post on this to follow soon). For building that in needed a drill so i thought i would buy one. As i just wanted to drill holes in aluminium i decided to go for a cordless drill because is will serve my purpose and just feels cooler. Therefore about 4 days ago i bought a cordless drill/screwdriver form Vasuki machine tools,Udupi (if you are the owner of the shop i need a discount next time).

Work was going on smoothly until one of us started to feel hungry. Now all we had at home were eggs so we decided to make an omelette. That is when this insane idea struck us that we should use the drill to make the omelette. Don't believe me? See for your self

After all this i started to work on my quadrocopter and in an a glue gun accident burnt my finger so we needed ice. The problem was that we had no ice in the fridge but for the past few days the fridge was acting up and had a lot of frost so we decided to to kill (or drill) two birds(getting ice and defrosting the fridge) with one stone. Here is what happened: