January 31, 2015


Since the mega clumsy RCX ESCs I got for my Trifecta build is very far from fitting in the tail I needed something smaller. I ordered a KISS ESC 12A (20A burst!) and it came in the mail yesterday. And it is small for sure. I can probably put two of these in the tail if I wanted to. A comparison to the Afro ultra lite would be interesting but I haven't got one in the drawer at the moment. Here's the RCX 12A Sky for comparison.

RCX 12A Sky and KISS 12A

January 30, 2015

Vario-F, NOT an alternative to SBS01-A

Since my previous post on the Vario-F I've been testing the device some more. In fact, today I took it for its for flight. And I noticed two things; the variometer is not reporting correct values and the e-fuelgauge had stopped.

Only getting the Vario-F to work wasn't easy. Registering the device in the remote (I'm using a 14SG) didn't work. It wasn't even close to working. While I was reading the Futaba manual I discovered that Futaba claims their sensors come with a default slot setting and if that setting works for the installation then no device configuration is required. I figured it was worth a shot and it turns out it works. Simply select SBS01-A on slot 3 and the numbers start coming in.

The Vario-F acts as a Futaba SBS01-A. The Futaba sensor reports both relative altitude and variometer, which is rate of ascent and descent. The variometer is most useful for detecting thermal effects on a glider aircraft. This is not important to me but it's worth mentioning that the Vario-F does not report a correct value for the variometer reading. Looking at the telemetry log it seems as if there's some random number between -1 and 1 reported.

In the aircraft I was testing the variometer in there is also an E-fuelgauge. This device has been reused a few times and I think it is now in its third craft. To my surprise, it wasn't reporting an increasing mAh count while I was flying. At first I thought I broke it but it turns out that if I disconnect the Vario-F from the bus the e-fuelgauge is working as it should.

This seems kind of scary. It is possible that the Vario-F does not implement the SBUS2 protocol correctly and causes other sensors to malfunction. This is a big issue since the SBUS2 is a multi-master bus. A multi-master bus uses the notion of gentlemens agreement in terms of occupying the bus and the introduction a non-compliant devices causes other devices to malfunction.

If someone was to put critical things like a servo on the SBUS2 port together with the Vario-F? Well that would probably not end well.

January 28, 2015


A while back I pledged a few bucks to the nano beams project on kickstarter. Essentially, nano beams are like maker beams but smaller and lighter. They'll come to great use when putting custom stuff on the flying machines in the future.


January 27, 2015

FPV250 Ghost replacement LED board arrived

I got the replacement LED PCB from HobbyKing today which enables me to install the board and the motor on the almost finished FPV250 Ghost. I got the wrong LED color on one of the boards with the frame and filed a complaint to HobbyKing. They sent me a new one.

Finally I can get started with dialing in the PIDs and checking out if it looks any good in the air with those LEDs on.

January 23, 2015

Cheerson CX10 range hack and a promo

I bought a Cheerson CX-10 a while back to bring to work to fly and let others try out flying. It's a great toy and except for the propellers it won't break. At least mine hasn't broken yet. It flies real well and has a stable hover for beginners to practice altitude control and get a feeling for the controls in general.

Mine however had ridiculously short range. Both in term of range and in term of obstacles. If anything, and I mean anything, was between the transmitter and the micro-quad it would fall dead to the ground. I figured something had to be wrong will my machine. It is very cheap and you have to live with some quality issues. My first idea was that the antenna was either missing or damaged. So I took it apart.

CX-10 inside antenna

As you can see from the picture the antenna is intact but it is located right where my finger will be while flying it. Most of the signal that should disperse to the front towards will instead just warm up my finger (very little, but you get the point).

CX-10 antenna moved to the outside

The solution was easy. I just cut a slot in the plastic case for the transmitter and bent the antenna slightly to let it pass out into the free air.

CX-10 external antenna

Now the antenna extends outside the transmitter and away from fingers instead of into them. The range is no longer a problem, at least at the office. But I haven't dared to fly into the bosses office yet...

Edit: The promo has expired since long...

January 22, 2015

FPV Headlights mk2

This is my second attempt at headlights for my mini-quad(s). This particular setup is made for the FPV250 Ghost I've recently put together (build page updated continuously).

This new version will sport a better LED and reflector, namely a Cree XM-L T6 700lm replacement module. The previous version used the HobbyKing headlight and I do expect this to be much more powerful or I'll be disappointed.

I'm going with a similar setup as last time. I'll use the same voltage regulator (although I know this is wrong) but will use a relay switch instead of an electronic one. The choice of switch is due what's on the drawer, I have an non-spec electronic and a speced relay. I'm using the relay that I know can take the punch. https://www.youtube.com/watch?v=rrMJiiyVUZQ#t=1200


Parts for the headlights


As usual I start with taking a part the things that have cables. I always replace them as they never seems to be of the right length and have the right connectors. The relay switch was stripped down to see what was inside, mainly to see the quality and how I can resolder the cables.

Relay switch, top side
Relay switch, top side

Relay switch, bottom side
Relay switch, bottom side.

And wow the soldering is just fantastic on this one. Not. I soldered new longer wires for connecting to the quads power connector and soldered the wires to the voltage regulator directly to avoid the additional connector.

Switch connected to the regulator
Voltage regulator connected to the power supply.

At this point I tested the setup. I first hooked everything up to a receiver to test the relay. I ran into a small surprise there as the relay triggers somewhere at 80-90% signal, not 50% as I'd expected. One enabled I dialed in the voltage regulator to the 4.2V stated on the LED module.

Now I connected the LED. It was bright. Too bright, and started flashing after a few seconds. This seems related to heat and could be a built in protection in the module. Because it got hot very fast. So did the voltage regulator. I had to dial it down while the LED was on to get a more sane setting. Once disconnected the voltage was at about 3V.

For this kind of setup you must use a current regulated power supply. I will test this one out to see if it handles the heat over a longer period. But you should not, this is wrong!

Anyway, I mounted everything on one of my favorite maker parts, a piece of glass fiber from the rotorbits series with pre-drilled holes.

Final assembly

And mounted it with velcro and a velcro strap on the mini-quad.

Mounted on the mini-quad
Headlights mounted on the mini-quad

Unfortunately I'm still waiting for a spare part from HobbyKing to complete the mini-quad itself and I it'll take at least another week before I get it. I'll update with night flight footage as soon as I get the parts and start flying it.

January 17, 2015

Vario-F, an alternative to SBS01-A?

I'm currently underway putting together my FPV250 Ghost edition and I thought I should give it something extra aside from all those LEDs. I noticed a while back that there was a variometer alternative to the rather expensive Futaba one. It's the Vario-F from EZC RC. It's rather cheap and there isn't that much information about it on the internet. Hence the first question, does it even work?

I've tested it now. Not flown it, but I got a first impression. The thing is that they probably reverse engineered the Futaba device to let the Vario-F imitate the SBS01-A in the SBUS2 bus. But, they did not implement auto configuration. This means that you cannot hook up the device to your transmitter and register/configure it as you would with a Futaba device. No configuration means no changing bus slots. The device is set up just like the SBS01-A in the sense that it defaults to slot 3 and occupies slot 3-5.

Once you know and accept the fact that it sits on slot 3 you can simply plug it into your receiver and configure slot 3 as a SBS01-A sensor. If you have any other sensors occupying slot 3-5 then you'll have to reconfigure them. I had to do that since I had the E-feulgauge on slot 1-3 and the RSSI "Temperature" reading from the E-feulgauge on slot 4.

But it worked out well after all and after running up and down the stairs it seems to work. I don't know much about precision and speed at this point since I haven't put it to real use yet.

Vario-F from EZC RC
Update: Please read my follow-up on this device.

January 13, 2015

They got the colors wrong

I started building my FPV250 Ghost Edition that was supposed to have been ready by now, but I've had other matters to attend to. Since the trifecta is now approaching I've started building it. I quickly noticed that the small LED boards for the arms are not marked in any way. There's no way to tell if they are red or green without connecting them to a power source.

So I did.

Too much green in this one

No luck this time. I've sent a support request to HobbyKing asking for a new one. We'll see how that turns out.

January 12, 2015

The Trifecta is here

HobbyKing finally launched "their" new mini-tri-copter, the Trifecta. I and many with me have been waiting some time for it to arrive, since HobbyKing has been leaking footage of it for some time now.

The frame is a close clone/copy/improvement on the pocketdrone frame. You can essentially build a full pocket drone clone using parts from the HobbyKing store, including the flight controller which is an APM, except for the folding propellers.

I managed to order one from the first released batch. I did not order anything else at the time as I wanted some more time to think through the setup. Their recommendations for their new frames haven't always been fantastic. I'm mostly thinking of the initial specs of the FPV250. I'v decided to pick up the drive train from MyRcMart this time. The last motors I got from them looked really good and they have good test data for their motors with different propellers. Something that HobbyKing does not. Here's my pick.

I ran the setup (approximate) through eCalc and got the results below. I think they're good enough to proceed it this point.

eCalc calculation with approximate values

I won't be ordering the tail servo as there should be one amongst the ones in my drawer that is fit for the task. Additionally I will use a CC3D flight controller and install a Unisense-E sensor. This is new to me and I want to try it out as it contains current, voltage and capacity sensors along with a vario and even a motor rpm sensor. It does however come with a price. The sensor alone corresponds to almost half the price of the machine.

Update: Please see the build page for further and updated information.

January 5, 2015

Decommissioning my first mini-quad

Since I have the parts waiting for my fourth mini-quad build there's a need to get rid of one of the others. My first mini-quad has been a fantastic machine for learning and crashing but it has some short comings and I need the telemetry receiver and flight controller for my next build.

But instead of just tearing it apart and letting the parts rot in a corner I will refit it with a spektrum receiver and a KK board I'm not using and give it to a fellow hobbyist that I think should get started with FPV.

This post is for remembering the machine and some of the mistakes I made while building it.

My first FPV250, last moment before decommissioning

I'll take it appart top to bottom through the layers of rotorbits and plywood.

The video transmitter

First off is the video transmitter. The placement of the device caused the antenna connector to break away when I flew into something.

CC3D on a plate of plywood

Below the transmitter is the flight controller. An original DroTek CC3D. Loved it from the start and it made me consider the KK as crap (more an that later). I'm still using servo connector pins on this one.

Receiver and current sensor

I squeezed in the receiver in the "bay" of the frame. HobbyKing always wanted a KK to sit in here as a flight controller. The CC3D could never fit, especially considering the USB-port on the side. I used a special cable to wire SBUS into the CC3D and used two PWM ports to control the pan-tilt of the camera.

Pan-tilt coming off
The pan-tilt from fatshark was something I never liked. I had to drill and saw to be able to mount it upside down and to move the cable that annoyingly came out the back of the mount. Later on one of servos died (electronically). You don't always get what you pay for.

The current sensor
This was my third use of the current sensor from tje.dk. Fantastic device that just works and I have a hard time living without it now. Too bad Faastest receiver plus sensors comes with a considerable cost, otherwise all my models would have them by now.

After having removed all the electronics except for the ESC and motors I installed a KK 2.1.5 board together with a DSMX receiver. I flashed the KK with steveis latest firmware and WOW was I surprised. A lot have happened since I was trying to get my stock KK and KK++ SBUS flying and it was only flying like crap. After about 5 minutes adjusting the transmitter and the KK settings I now have a basic configuration the does what it should. Ready to give away and for someone else to give it eyes and learn how to fly.

FPV250 with KK board, the way HobbyKing wanted it