I hadn’t gotten around to modifying the internals of my TX so I figured I’d have a go at reflashing the Hobby King 20A (F-20A) ESCs first. I chose this ESC because:

• They were really cheap
• They supported reflashing with SimonK’s firmware
• They had their test pads in a row so it would be easier
• All it’s FETs were the same (N-Channel)

Some wiring had to be done to match the pin-outs from my 10 pin AVR programmer to the test pads on the ESC. I found the information that I needed over at this RC Groups thread. I also read the instructions found here at openpilot.

As for the firmware we can find it on github along with more useful instructions. I suggest you read all of it and refer to this spreadsheet for your particular ESC.

I wanted to test this really quickly so I just slapped some wiring together with a breadboard to get everything hooked up.

The test pads are in the following order: MOSI, MISO, SCK, -, +, RESET (from bottom to top). I took the time to tin the wire, that I took from an old IDE cable, to make sure I had good contact and no stray wires crossing pads. I then lined it up and held it in place with some scotch tape so that I didn’t have to keep holding it there. The tape doesn’t really maintain the contact so prior to programming I would still need to use my finger to press down, it just keeps me from fumbling around.

With the wiring done, I plugged the AVR programmer into the USB port and fired up AVRFuses.

I set the device to “ATmega8″ which is the microcontroller found on this ESC, and probably most other ESCs compatible with the SimonK firmware. I also pointed the hex file to the firmware file that I had downloaded for my ESC. Then I took a deep breath, pressed my finger to the wire on the ESC and clicked on program. A few seconds later… “SUCCESS”.

I unhooked the ESC and reconnected it to a battery, servo tester and motor. Upon doing this I heard 3 beeps followed by a 4th telling me that everything was good. A few twists on the servo tester and the motor was spooling like a dream.

The flashing instructions make mention of the fuses on the ESC. We do not need to do this and can leave it stock.

In case something was changed accidentally (and you still have access to the ATmega) here are the default fuse settings as seen by AVRFuses.

I, on the other hand, somehow managed to mess things up and bricked 1 of my 4 ESCs during the process. Not too bad for my first time doing this, but now I had to go order another ESC. I’ll probably buy a few as spare.

It was also voltage selectable (3.3V and 5V) via adding or removing a 0ohm resistor. I plan on replacing the resistor with headers and a jumper later. It comes default as 5V which works for me, so I’ll leave it for now.

I run OS X, and most guides for things related to R/C are written for windows. I basically looked for the equivalent Mac based tools as described by the Windows based guides. I knew that I could do this cause there is nothing platform specific when it comes to working with the Atmel microcontrollers (the atmega8a that controls our ESC).

I chose to use CrossPack, by Objective Development Software, to provide me with the toolchain for working with the Atmel microcontrollers. And while I’m pretty comfortable with the OS X command line (many years of Linux), I figured that I wanted to be lazy and have a GUI interface. Thus I also chose to install AVRFuses, by Jason von Nieda, as the GUI that would hook into avrdude (comes with CrossPack and is the actual program that will flash the firmware to the ESC).

At the time of writing this, the versions that I used are (on OS X 10.7.4):

• CrossPack-AVR-20120217.dmg
• AVRFuses_1.4.4.zip

Installation is a piece of cake so I won’t go into that. I will however talk a bit about configuring AVRFuses so that it can talk to the AVR Programmer through avrdude.

After installing both pieces of software, open up AVRFuses and go to it’s preference pane. Here we will need to define “Path to avrdude” and if you read the readme file that came with CrossPack, you would know that it installs by default to “/usr/local/CrossPack-AVR-20120217/” and the full path to avrdude is “/usr/local/CrossPack-AVR-20120217/bin/avrdude”.

The programmer that I bought was USBASP so I selected “usbasp” (obviously), You may need to select a different option depending on your programmer. The port should again be selected based on the hardware programmer that you are using, and it is pretty safe to leave the baud rate at “[Default]“.

There has not been an update to AVRFuses since 2008, but I wanted to leave the option checked in case Jason decides to do something someday. I also left “Show avrdude Command Lines” so that I could monitor what was going on Click on “Close” and if everything is good you will see a nice green “SUCCESS” in the output console.

Now we can get ready to reflash the TX and some ESCs. I’ll write about those later on.

Here is a walk through on how I installed the Turnigy 9x LED backlight kit from hobbyking.com. You get a foam backing and the actual backlight panel that has a wiring harness attached to it.

As my old soldering iron is fried, and all I have my butane field iron, I am only going to do the plug and play install for now. I don’t really want to use the field iron to solder things to the TX’s logic board as it is not precise enough.

To start, I removed 6 screws on the back of the transmitter to crack it apart. I had to do this carefully as the front and back pieces are connected by a cable that has to be unplugged from the logic board.

Next I carefully unclipped the ribbon cable that was connected to the top of the logic board. This is the only cable that I disconnected for fear of damaging it when I flipped the logic board up to access the LCD panel, and tear out the old foam backing.

After this I removed the 9 screws that held the logic board in place. These are of different size so I laid them out on the table the way I had removed them so that I would not place them in the wrong place later.

With the logic board free, I now had access to remove the thick foam backing that was going to be replaced.

After a bit of tugging and prying, here is the logic board with the foam backing removed. I am going to be replacing this with the thinner one included in the kit. This is to make space for the extra thickness that the LED panel adds to the mix.

With the foam padding on, I then position the LED panel on top of the LCD panel. The instructions from hobbyking as the wiring on the right together with the 4 directional buttons. I choose instead to have mine positioned the other way as it was easier to avoid the wiring interfering with the buttons. On the left, there are only 2 buttons to contend with, and thus I had more space. The LED panel is taped in place and the logic panel with the new foam backing sits on top of it.

I secured the logic board back in place and you can see that having the wiring come from the left also made things much neater top side cause I don’t have as much excess wire to deal with.

The finished product after reassembly.

Together with this order, I picked up the Frsky DJT module with telemetry, an extra D8R-SP receiver cause I wanted the PPM signal, Zippy Compact 2200 Lipos, the 9x backlight kit in white, and a few other odds and ends. Now I can actually start taking some stuff apart and modifying it, cause to me that is part of the fun of this hobby.

In the next box I received the sensors that I ordered, cause it wouldn’t make much sense to have telemetry if I don’t at least send some data across. For now I settled on the voltage sensors, cause that’s the most important thing to keep track of when flying. I picked up both the individual cell sensor and the analog pack sensor so that I could get both the total pack reading and the individual cell reading (You will need both sensor if you want both types of readings). I also ordered the sensor hub to tie them both together to the D8R-SP.

Hobbyking was nice enough to throw in a set of Turnigy stickers as you can see. That will work as some cool graffiti for my tool cases. Stay tuned for posts about the mods and how they work out.

Woo Hoo! I just received another parcel! It’s the motors that I ordered on aliexpress.com. These are A2212-930KV Brushless Outrunners and they cost me USD38 shipped. I don’t think you can find a better deal elsewhere. If you do, please drop me a note… lolz…

They came in one of those bubbled envelopes, and they were wrapped in a lot of bubble wrap. On top of that they were individually packed into pretty rigid plastic so everything was very well protected.

This is what you get in each plastic container. The motor and prop adapter are very nice. I can’t really say the same for the motor mount and the 4 screws that came with it. These seem a bit soft so I’m probably not going to use them.

Here’s everything unpacked. What you see is what you get for USD38 shipped. Not too bad.

The 2 main things here are the power distribution board and a bluetooth module.

The power distribution board costs USD0.86 plus shipping. You can’t really beat that. As you can see, it can handle up to 8 segments. The quality of the board is nice and it had nice big pads to attach your power cables to.

The bluetooth module was better than I had expected. Sunsky didn’t really have much specs on it, but their site indicated that the module operates at 3.3v. Upon inspecting the unit and searching around, I was pleasantly surprised that it had on-board regulation for 3.3v-6.5v. So no headaches of setting up a separate power supply when I use this on the quadcopter later.

In case you are wondering, the BT module reports back as a Linvor 1.5, and is actually running the HC06 firmware. This firmware is basically stripped down and only accepts a handful of AT commands. You could if you wanted (with a bit of technical know how of course), load a more powerful HC05 firmware in.

The first part is finally here! I put in an order for a SK450 frame on aliexpress.com. When I ordered this, hobbyking.com had not started to carry it yet, but now they do so you can get it there. I was lucky and picked it up at aliexpress.com for USD26 including shipping so I don’t think I paid much more than buying from hobbyking.com (They sell it for USD17 before shipping).

I comes packed in a small box that got slightly crushed during delivery, but overall, no damage was done and I’m pretty pleased cause everything is packed nicely inside.

Here is a picture of all the parts laid out. The quality of the pieces is excellent. Tolerances look good, and moulding looks precise so everything should fit together well. It even includes a nice set of instructions.

A hex tool and a few minutes was all it took to put everything together. Everything fit into place nicely and nothing was missing. They even threw in a couple of extra screws just in case.

I’ll put up something about the performance of this frame later when I actually get to fly it. I basically bought this cause it was a plastic frame (I’m hoping that it’ll be a bit more resilient than aluminium cause I’m still learning to fly). This particular frame has arms that seem to be clones of XAircraft’s X450Pro which I really liked so I figured I’d try it out. There are similar looking plastic frames like the DJIs and their clones, but it seems that those have vibration issues so I stayed away from them.

Can’t wait for the other things to arrive!

Everything seen here was DIY and done from home in the car park. I used a fairly simple equipment setup as space was a concern. You’ll probably find the equipment really old compared to what you guys have nowadays. I had some stuff lying around and I like the old equipment cause I’ve tested some of the new stuff and they just do not seem to be built the same anymore.

Equipment List
Head Unit: Pioneer DEH-P80RS
Front speakers: 4″ MB Quart 2-Ways
Sub: 8″ Rockford Fosgate 4 Ohm SVC
Front Amp: Nakamichi PA-304
Sub Amp: Nakamichi PA-302

As you can see, I’m running a simple 2.1 system. The HU was choosen for the 3-way crossover and time alignment capabilities as I did not want to install a separate signal processor. It also has the ability to turn off the internal amp (reduces noise) and has high volt pre-outs for better SNR. Great unit overall, but I wished it had a parametric EQ for better tuning.

The 2 nakamichi amps are very clean as there is no extra circuitry for crossovers or signal processing, again in line with my need to lower the signal noise. the 304 is run in 4 channel mode (4x45W @ 4 ohms) to power the L/R mids and tweeters. The 302 is in bridge mode (1x160W @ 4 ohms) going to the RF sub.

I was looking for Sound Quality so did not see the need for high power amps or a large sub. Thus the 8″ RF unit in a 0.29 cubic foot sealed enclosure.

Everything was designed to be removable so that I could go back to stock and keep my equipment.

The front speakers are on the dash as far away as possible to minimise path-length difference. The pods are made of fiber-glass and MDF rings. A mould of the dash and A-pillar was taken to build the base of the pod, then the MDF rings were added and the whole thing fiber-glassed to seal it up. A layer of rubber coats the inside to reduce resonance and is filled with polyfill to increase air mass. It was then wrapped in speaker cloth and attached with silicone to the dash.

The head unit is cleanly wired. All connections are soldered for conductivity, covered in heat-shrink tubing (I do not like electrical tape as it leave a sticky residue and looks horrible) and tied off. I did not use most of the stock wires except for ‘acc’, thus all unused wires were heat-shrinked over to prevent shorting and tied off. Ground goes directly to chassis and power is straight from the battery through a 1-4 distribution block. 2 gauge wire is used from battery to block with a 60W fuse in the engine bay 6 inches from the battery. Signal cables are home made with gold plated connectors and heavily shielded coax cable.

Due to the lack of space and wanting the signal cables to be as short as possible, the amps are placed under the car seats. 8 gauge cables are used for power and ground. All power and signal cables were not allowed to cross to prevent introducing noise into the system. 22 gauge is used for remote signal from the head unit wired in a daisy chain. The remote wire does cross the signal cable, but it was done at 90 degrees to prevent noise. I’m not entirely pleased with the amp presentation under the seat but am too lazy to work on a fiber-glass cover to beautify it.

The sub is placed in the trunk within the spare tire to save space. I wanted to keep the spare tire so a mold of the inside of the rim was made from fiber-glass and the enclosure was made. I did some rough calculation before making this to ensure that I had enough air volume for the sub. 0.3 cu Ft is recommended, and I estimate that I could get very close to that by measuring the internal radius of the rim. I had a bit of space above the rim and below the read covering board so it all worked out. The sub thus sits inside the spare tire covered by the original board and no space is given up in the trunk at all.

Tuning was done with a RTA and a pink noise testing CD. Unfortunately the head unit only has a 16 band graphic EQ, so I could not entirely flatten out the overall response. However for my purposes I don’t think I need to add in a parametric EQ for better tuning. I’ve not had problems with vibrations yet, but some sound deadening would be nice.

Everything was done at home over the course of 1 1/2 years when I had the time away from work and other hobbies. Like everyone else, it will always be a work in progress.

Unfortunately I didn’t take picture during the build as I normally do not post things and I’ve been DIYing since 1996 on my cars. What you see here is basically the finished product, but I can answer any questions if you are wondering how anything is done.

Some extra pictures below.