Browsed by
Category: Multicopter

Hubless Frsky telemetry with Baseflight on Naze32

Hubless Frsky telemetry with Baseflight on Naze32

It’s been about 2 weeks now since successfully setting up the stm32f103 toolchain on my mac. Darn that was hard. Anyhow, I wanted to play around with telemetry for the Frsky receivers since ER9X supports it. I do have a hub, but one thing that bothered me was that to get the telemetry, we would be buying and installing a bunch of sensors that our main flight controllers already have.

With this in mind I set about to seeing how Baseflight on the Naze32 could output it’s own sensor readings directly to the Frsky receiver so that we could use those readings instead.

So to cut a long story short, it worked. I submitted the code to Timecop, and he was nice enough to clean it up and merge it into the latest release. We now have telemetry output for:

  1. Barometer
  2. Accelerometer
  3. Gyro temperature
  4. GPS
  5. System up time (in the time field for Frsky)

To activate this you’ll need to download and install the latest revision of Baseflight and enable telemetry with feature TELEMETRY from the CLI. Remember to save after that.

You’ll also need a level shifter between the Naze32 and the Frsky receiver. Below is the design I used. You’ll only need the top TxD -> RxD' portion.

Image from http://www.kswichit.com
Image from http://www.kswichit.com

Timecop has also designed a small adapter which would be a lot cleaner from an installation standpoint.

Level shifter for Naze32 to Frsky receiver by Timecop.
Level shifter for Naze32 to Frsky receiver by Timecop.

I’m still hoping to get multi-cell Lipo information as part of the stream and not just VBAT. This will require using something like the FLVS-01 lipo sensor with a direct connection to the Naze32. Gonna take a look at that next.

ESC reflash with SimonK firmware

ESC reflash with SimonK firmware

20AUBEC

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.

IMG_0490

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

IMG_0491

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.

avrfuses-program1

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.

default-fuse-F20A

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.

Installing the Turnigy 9x backlight kit

Installing the Turnigy 9x backlight kit

IMG_0477

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.

IMG_0469

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.

IMG_0472

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.

IMG_0474

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.

IMG_0475

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

IMG_0476

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.

IMG_0478

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.

IMG_0480

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.

IMG_0481

The finished product after reassembly.

Turnigy TX finally here

Turnigy TX finally here

Two boxes arrived today. Both much anticipated from hobbyking.com. The box hold the Turnigy 9x that I’ve bben waiting for. This TX sells so well that it is perpetually on back-order, and the do not allow placing pre-orders on it. Basically you subscribe to their email notification and when you get it, you rush to their site and place your order for it. Normally it sells out within half an hour of the email notification so you have to act fast. Lucky me for finally snatching one. I can’t wait to get all the mods done (I’ll document those on the blog too).

IMG_0465

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.

IMG_0468

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.

A2212 Brushless Outrunners

A2212 Brushless Outrunners

IMG_0449

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…

IMG_0451

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.

IMG_0452

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.

IMG_0453

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

Power distribution and BT

Power distribution and BT

More stuff has come in. This time from sunsky-online.com. I’ve had good experience with them and I find them much more reliable than GLB, cheaper too.

IMG_0458

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 SK450 frame

The SK450 frame

IMG_0427

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).

IMG_0428

It 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.

IMG_0430

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.

IMG_0445

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!