Code 42

So, I've ordered, and received the components (see my earlier post ) to build my F550 Hexacoptor. So, now it was time to start building. I ordered 3 pairs of Multistar 2212 920KV Motors. I got 3 boxes with the motor pairs. The Multistar 2212 920KV CW/CCW Motor pairs with Props The package came with the 3mm hex nuts to mount the motors, and bullet connectors with heat-shrink tubes to connect to the ESCs as well. The propellers are 9043, and each box has an extra pair of props as well. The 9043 Propellers that comes with the Multistar Motors

When we are building RC models (aircrafts, multicopters etc.), something we typically overlook is what type of wires to use to distribute power in them. Usually, we try to reduce the weight of the model, so we tend to go with smaller wires. But, we cant expect to put in small circuit-wires and have them handle the amount of power needed. If you look at the wires that comes in the output leads of a Li-Po, or the wires that comes on a standard XT Jack, you'll notice that they're quite huge. Large gauge wires on a Li-Po and XT connectors These need to be huge to handle the amount of amperage that goes through them. So, we should also consider the amperage, and the length of wire needed when selecting the size (gauge) of the wires.

Since I received my NAZA-M Lite and the F550 Frame, now it was time to select the other components to build the hexacopter, namely the Motors , Propellers , ESCs , and the Battery . Now, if I have gone with the DJI ARF Kit, it would have included all the matching motors, props and ESCs. Since I opted to get the NAZA and the components separately, I needed to find a set of motors, ESCs and props which works with the NAZA-M Lite, and the F550 frame. After some research online, I managed to come up with the following requirements for the components that would word with the NAZA and F550, Motors : 2212 920KV - 3 pairs of CW and CCW (6 total) These typically draw about 20 Amps of current. Note: To learn what the numbers on a brushless motor mean, check out  this guide . Propellers : 8 x 4.5  or 10 x 3.8 It's recommended to use  8 x 4.5  if you're using a 3S battery, and  10 x 3.8  if it's a 4S battery. To learn about propeller size numbers, check...

Have you been trying to shop for propellers - either online or at a hobby shop - and got confused of the numbering used to denote the size of the propellers? You see things like " 10 x 4.5 CW ", or " 8055 CCW ". What do these numbers mean? A 8 x 4.5 CW and CCW Propeller Set It's actually quite simple once you figure it out. The first number denotes the diameter of the prop (length from tip-to-tip). The second number denotes the pitch of the prop. Here, the pitch is denoted as a length, not a angle. Let's see how that works.

The F550 Frame, which I ordered from eBay, finally arrived. The shipment did get a bit delayed than I thought, but considering it was a holiday season I'm OK with that. This F500 (or HJ550 as labeled on the box) is also not the genuine DJI branded one. It's a clone similar to the F450 frame I reviewed in my last post . The F550 Frame in the box It comes with the 2 PCB plates (with the integrated power distribution lines), 6 arms (in 3 colors), and the nuts and bits to put it together. 2 Plates, 6 Arms, and the Nuts

I was going through a local hobby shop, and to my delight, I found that they had a F450 Frame on sale. They said it's the last one in their current stock (but they said more stock is on the way). I'm still waiting for the F550 frame I ordered from eBay. Although the F450 wasn't exactly the one I was looking for, I decided to buy it and give it a try also. For those who aren't familiar, the F550 is a Hexacopter frame, while the F450 is a Quadcopter frame. The F450 Fame I found The F450 I bought didn't have the DJI branding, so I'm guessing it's a clone. But I can say, it's quite a good quality one.

Finally got the DJI NAZA-M Light I ordered. It did get delayed - came about 2 weeks after the expected delivery date, which I'm guessing was due to the holiday season. But finally since it arrived, I wasted no time on unboxing it. The NAZA-M Light came in a neat little box It came packed in a pretty nice box. I was actually expecting 2 boxes, since I ordered the GPS unit as well. But it turns out the GPS Unit box comes inside the main DJI NAZA box. The GPS unit fits nicely inside the main package So, let's unpack everything and see what we got.

I have now ordered the DJI F550 Frame for Hexacopter, and the DJI NAZA-M Lite Flight Controller. I found 2 sellers on eBay that ships to my location. The Frame was bought from here: eBay Link The DJI F550 Frame The kit contains the 2 top and bottom plates, 6 arms, and the mounting nuts and screws. It comes unassembled, but as per the video tutorial I posted in my earlier post, it's quite easy to assemble. I'm hoping the package arrives within 2 weeks.

I'm thinking of starting my multicopter project again, with the DJI F550 Frame. I'm currently looking at the following resources, http://www.helipal.com/dji-flamewheel-f550-w-naza-v2-gps-drone-rtf.html http://dronebly.com/the-ultimate-guide-to-dji-f550-hexacopter-things-you-need-to-know And, the following videos,

A Friend of mine, Harsha Wijesooriya , has started a group called Model Aircraft Clinic, which aims at addressing technical issues and problems faced by model aircraft flyers. There will be discussions going on by RC model flyers on issues, damages, fixes, and solutions they had with model aircrafts. Model Aircraft Clinic Logo - https://www.facebook.com/groups/AircraftClinic/ Check them out here at FB .

It's been 6 years since I last posted on this blog. 6 years.... That's a long time. Some life and career changes made me move away from some of these hobbies I had. But now I'm thinking back. I want to start again. DJI Phantom - By Vicki Burton from United Kingdom (DJI Quadcoptor Phantom Vision Plus) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons Shall we start again? I know it wont be easy. I'm 6 years outdated in the model aircraft hobby. The technology has advanced in the past 6 years. Model aircraft designs has become advanced, and smaller. Drones, multicopters are practically everywhere now. But, I guess, the basic principles of model aircrafts hasn't changed. So, I should be able to catch up again. Let's start.

It's been another few weeks, and I'm back to building my quad. Since I recently got my transmitter, it was time to start building the electronics of the quad. The AeroQuad project ( link ) is based on an Arduino for the flight control. It basically uses a 3-axis Gyro and a 3-axis Accelerometer for the flight sensing (other sensors such as Magnetometers and Barometers are also supported, but optional: more info ). To connect these sensors, AeroQuad offers a 'shield' for the Arduino ( What is a 'shield'? ). The sensors need to be bought separately. There are 2 shields, AeroQuad Shield v2.0 ( link ) for Arduino Mega and AeroQuad Shield v1.9 ( link ) for Arduino Duemilanove. Since I already had an Arduino Mega, I ordered the 2.0 shield. With the normal shipping method, it took about 3 weeks to arrive. The shield kit included the following, AeroQuad Shield v2.0 Kit The shield PCB The Logic Level Converter 2 resistors (15K and 7.5K) ULN2003 IC 3 LEDs ...

It's been over 2 months since I posted the first post on building a quadcopter ( link ). You would've thought that I must have completed the build by now. But actually, I couldn't do much. Mainly because that my transmitter shipment got late. As you remember, I ordered a HK-T6Av2 from HobbyKing ( link ) (Actually, a friend ordered it for me as a gift). It was shipped on 21st March. Usually takes less than a month to arrive. But since I didn't receive it until 25th April, I made a complaint to HobbyKing. They said they'd start an investigation on it. On 11th May, the Hong Kong Post mail tracking reported that the parcel was returned to sender. Why was it returned? no one knows... Anyway, I contacted HobbyKing again and they said they can arrange it to be resent once it reaches their warehouse. The parcel reached them on 25th May and it was re-shipped on 31st. It finally arrived about a week ago.... So, here it is... It's finally arrived... I have to sa...

Note: This is the start of the 'My Projects' section. This is where I post about the projects that I personally do. You can track my progress, my decisions and their outcomes for the problems I face and of course failures (sort of...). So, I hope you enjoy this as much as I do and please leave comments. Ever since I started building model aircrafts I wanted to build a Quadcopter (a.k.a. Quadrotor). I was fascinated by their agility, their simple design and control but need of a complicated stabilization system. The only thing that delayed me to build one is the relatively high cost for the components. But finally I found an opensource quadcopter project named AeroQuad ( link ) which was just within my budget. So, I started gathering my resources... The first thing I needed was a good Transmitter/Receiver pair, which turned out to be a problem because a good pair costs a lot. A quad will need at least a 4-Channel one. That's a bare minimum, so a 6-Channel one would be th...

Note: It's been about 2 months since I've posted the part 3 of this article. Sorry for being late with this part. I hope you have read my earlier articles on Li-Po batteries (Li-Po Batteries Explained Part 1 , Part 2 and Part 3 ). Now let's look at the most important part - charging and maintenance. First of all, why is this so important? Well, just watch the following video on what happens when you mistreat a Li-Po battery. So....., now that you've seen the dangers of Li-Po batteries, it should be clear that they should be handled with care. Li-Po's are very different from conventional rechargeable batteries, so you should only use a charger specifically designed for Li-Po's. Doing so will increase the life span of the Li-Po battery pack and yours as well.

If you have studied about brushless motors, you'll probably know that they need a electronic controller (ESC) to run. Since the ESC can't actually see how the motor is running,  it needs to somehow detect the orientation of the rotor (moving part) relative to the stator (stationary part) of the motor. The two most popular ways of doing this is to use a Hall Effect Sensor or to measure the Back EMF of the undriven coils. The Back EMF method does not require any additional sensors, but it's implementation is complicated and has to overcome several issues. The Hall Effect method is much simpler than that, but requires a Hall Effect Sensor near the rotor of the motor to operate. So, how does a Hall Effect sensor work? Simply put, it is a device that varies its output voltage based on changes on a magnetic field. The operation of the sensor is based on the Hall Effect which was discovered by Edwin Hall in 1879. The theory is explained as follows,  The Hall Effect

If you go shopping for Brushless motors you will be confronted with a lot of numbers to choose. For an example, you would see motors marked with 3632 22turn 1500Kv, 2213 20turn 920Kv etc. So what does all those numbers mean, and how would you choose? Here's a simple guide... Let's take this motor for an example, Turnigy 2213 20turn 1050Kv Outrunner It's marked as "2213 20turn 1050Kv Outrunner". Let's see what it means. First of all, it's clearly written that this is an Outrunner motor. The "2213" indicates the size of the stator, First two numbers = diameter of the stator = 22mm Second two numbers = length of the stator stack = 13mm

Using a popular PIC microcontroller such as the 16F877A and a high level compiler such as mikroC, you can do a lot of things. In the last post I discussed about how to get a PWM signal based on an analog signal. Now let's try to do extend that and try to get 2 PWM signals from the same PIC chip. Why would you need 2 PWM signals? Let's say you are building a robot, and you have 2 motors that need to work independently. Or 2 servos you need to control separately etc. As you know, the CCP (Capture/Compare/PWM) module in a microcontroller is responsible for generating PWM signals. So, to get 2 separate PWM signals, you need a microcontroller with 2 CCP modules. If we look at the datasheet ( link ) of the 16F877A, we can see that it has 2 CCP modules (PIC16F87XA Datasheet - Section 8). So, now let's get our PWM signals... However, there's one thing you have to know when you use the 2 CCP modules together. If you look at Table 8-2 from the datasheet, when you configure...

If you like to experiment with microcontrollers you've probably tried out analog-to-digital conversion and generating PWM signals. Using a popular PIC microcontroller like the 16F877A, which has both ADC and CCP (Capture/Compare/PWM) modules, you can test out both of these easily because mikroC provides easy to use library functions for both of them. (Most of you will be familiar with these libraries, so I won't be going in to much detail about them here. Leave a comment if you like to learn more.. :) ) Now, think of a scenario like this: You want to change the duty cycle of your PWM signal based on a analog signal. It can be from a variable resistor that you want to use to increase or decrease the duty cycle, or it can be a feedback from a sensor which is analog. So, how can we do it?... we simply use the ADC to convert the analog signal and use that value as the duty cycle value. All we need is a microcontroller that has both a CCP and a PWM module. As I said before, the...

If you've read my previous posts about Li-Po batteries (Li-Po Batteries Explained Part 1 and Part 2 ), you'll now understand the basics of Li-Po's. Now let's look at some standard ratings of Li-Po's that you'll need to consider when you buy them. Voltage A single Li-Po cell is rated at 3.7V. This however doesn't mean that the fully charged voltage of a Li-Po cell is 3.7V. Actually, Li-Po cells have a minimum voltage of 2.7V (fully discharged) and a maximum of 4.23V (fully charged). The 3.7V is just the average operating voltage of a single cell. Many Li-Po battery packs have two or more cells connected in series to provide higher voltages. The cell count of the battery pack is denoted by the 'S' number. A 2S battery pack means that there are 2 cells connected in series, thus providing 7.4V. Here are some examples of standard size battery packs: 1S = 1 cell x 3.7V = 3.7V 2S = 2 cells x 3.7V = 7.4V 3S = 3 cells x 3.7V = 11.1V and so on....