How to flash a ZTW Spider 30A OPTO ESC with the latest SimonK firmware by using an AFRO USB programmer

Parts needed:

ZTW Spider 30A OPTO Esc

Afro ESc USb Programming Tool

RapidFlash ESC Chrome App


  1. Connect ESC to the AFRO ESC Usb programming tool (the – and the signal pin)
  2. Connect the battery to the ESC
  3. Open RapidFlash app
  4. Choose the COM where Afro USB tool is connected to
  5. Choose Afro ESC USB linker
  6. Choose Latest (master)
  7. Choose bs_nfet as your firmware
  8. Press Flash Firmware (click in the reverse box if you want the motor the run into the opposite direction)

UAS Photogrammetric Point Clouds: A Substitute for LiDAR?

Download the pdf here

No topic in the remote sensing community was hotter in 2014 than Unmanned Aerial Systems (UAS) and it appears that will also hold true for 2015. Arguably the biggest UAS news over the past few months has been the commercial release of LiDAR systems for UAS, with a number of manufacturers succeeding in reducing the size of their LiDAR sensors so that they can be mounted on UAS platforms. Given that there is now LiDAR-based UAS it begs the question as to why one would even consider a photogrammetric UAS solution in which topographic data are produced from overlapping images?

Despite the advances made in shrinking LiDAR sensors, they are still larger and heavier than the cameras used for photogrammetric UAS solutions. LiDAR sensors thus require a larger UAS platform with greater lift capacity than a comparable photogrammetric UAS. Larger UAS platforms have an inherently greater risk associated with them. There is a big difference between a 1.5 lb. Styrofoam fixed-wing UAS loosing power and gliding to the ground versus a 17 lb. hexicopter with a LiDAR sensor falling from the sky.

LiDAR UAS solutions are also substantially more expensive and require a higher level of technical expertise to operate. With a lower purchase price, smaller and safer platform, and ease of operation, photogrammetric UAS options are an attractive solution to those seeking on-demand topographic mapping. This begs another question, are UAS photogrammetric solutions accurate enough? I will get to that answer later, but first a bit of a back story.

Commercial photogrammetric UAS have been around for a number of years. I first became interested in these systems a number of years ago when Hurricane Irene devastated Vermont’s transportation network by dumping inches of rain in a matter of hours, flooding roads, and leaving one town completely cut off from the outside world. Despite the vast network of satellite and aerial systems capable of delivering remotely sensed data, cloud cover and challenges in compiling a collection deck in a timely manner confounded acquisition.

Even if these issues had been resolved it was not clear that the data could have been delivered with requisite specifications within a timely manner. Fixing roads required mapping-grade, or in some cases, survey-grade data to make detailed measurements. Traditional field survey techniques were not possible in many cases due to the inherent dangers involved, and the extent of damage would have exhausted the number of surveyors available even if it were possible. In the absence of data, decisions, such as estimating fill volume for washed-out roads, were often made using the tried, but certainly not true, “ocular estimation” approach.

UAS certainly seemed to be the remote sensing solution needed for these types of situations. With funding from the U.S. Department of Transportation we set out to evaluate the ability of commercial UAS photogrammetric solutions to deliver GIS-ready data suitable for accurate measurements and mapping. We purchased a senseFly eBee, a lightweight (1.5 lb.) UAS with a 38 inch wingspan that uses a digital camera to produce orthoimages and photogrammetric point clouds in LAS format.

Generating these products requires accurate flight planning, to insure sufficient image overlap, and photogrammetric post-processing software. The eBee is accomplishes this through a tightly integrated workflow in which eMotion software is used to plan the flights (Figure 1) and Pix4D’s Postflight software is used to produce the 2-D and 3-D products (Figure 2). While any system requires some level of expertise it is hard to imagine making it any easier to generate photogrammetic point clouds than the eBee does.

Before I get into the accuracy of products from photogrammetric UAS it is important to discuss their capabilities and limitations. The eBee, and similar systems, are small, lightweight, and battery powered. Onboard systems track the location using GPS and gather key flight parameters such as wind speed. The FAA’s proposed small UAS 500 foot flight ceiling means that such a system could map several hundred acres in a 30-40 minute flight. By using a few batteries you can map a good-sized area, but you are not going to map your town (at least in a day) with one of these small UAS.

Now let’s get to the fun stuff–point clouds! Figure 3 shows a point cloud produced using the eBee workflow. As mentioned before the point cloud is in LAS format, which opens up traditional workflows developed for LiDAR data. Quick Terrain Modeler, Applied Imagery’s popular terrain analysis software was used to display the point cloud and perform the cross section profiles of the stream.

The point cloud looks stunning, but there are some obvious differences when compared to LiDAR. There are some data voids caused by shadows and there are no points under the tree canopy. The points are not data rich like LiDAR (e.g. no return information), but they are colorized automatically from the imagery, and unlike LiDAR, there are points for the water.

There are some obvious errors, but given that Figure 3 shows only 1/6th of a dataset gathered in a 30-minute flight, followed by 2 hours of post-processing with little user intervention, the results are impressive. Getting a point cloud for a couple of miles of river the same day you fly it would have been unheard of a few years ago.

How do photogrammetic point clouds stack up to LiDAR? Figures 4a and 4b show a UAS photogrammetric point cloud and a traditional LiDAR point cloud from a manned fixed wing collect processed to USGS QL2 specs for the same area. If you are having second thoughts that the point clouds are of the same area you are not the blame. The traffic circle seen in the UAS point cloud was constructed after the LiDAR was acquired.

This gets to one of the chief advantages of UAS, the ability to gather high-resolution topographic data when you need it, at a low cost. The UAS point cloud obviously has a higher point density, averaging nearly 50 points per square meter, compared to the nearly 3 points per square meter of the LiDAR data. Point density is, of course, not a definitive measure of quality. Despite that ground control points (GCPs) were not used, the UAS data were within half a meter of the LiDAR data on the horizontal plane, but the absolute vertical difference exceeded 50 meters.

GCPs narrowed the differences to tens of centimeters, both horizontally and vertically. GCPs do add another layer of complexity to the UAS data collection, and in disaster response, laying out GCPs might not be feasible due to time or safety constraints. For a number of use cases relative vertical measurements are what is needed.

With this in mind we measured a number of buildings that remained consistent in the two datasets (Figures 5a and 5b). Differences in the height measurements were always less than 30 centimeters, indicating that rapid accurate relative vertical measurements are possible using photogrammetric UAS workflows.

The title of this article was slightly provocative, and one could be tempted to slide into the LiDAR vs photogrammetry debate. Photogrammetric point clouds are certainly not LiDAR point clouds, but when factors such as cost, safety, timeliness, and acquisition area are considered, they might offer a superior solution. I believe that photogrammetric UAS will offer attractive solutions to many mapping and survey projects for years to come. Recent advances in photogrammetric UAS, such as the eBee RTK, which yields data with horizontal and vertical accuracies of less than 5 centimeters, will blur the lines between LiDAR and photogrammetic point clouds.

Disclaimer: The views, opinions, findings and conclusions reflected in this presentation are the responsibility of the authors only and do not represent the official policy or position of the USDOT/OST-R, or any State or other entity.

Jarlath O’Neil-Dunne is the Director of the University of Vermont Spatial Analysis Laboratory. He specializes in solutions that provide actionable information from high-resolution remotely sensed data.

Download the pdf here


A cheap Mobius GoodLuckBuy gimbal

After searching for a cheap gimbal for my mobius camera my eyes fell on a mobius goodluckbuy gimbal which is in theory is designed to be used with a GoPro camera but I read in the comments that it can be used with a mobius camera as well. So I bought one with just 55$ (44€). That included both the 2 motors and the controller. It’s a bit on the heavy side but for 55 dollars that was the best value for money gimbal I have found around.

DJI Phantom Brushless Gimbal Camera Mount w/ Motor & Controller for Gopro3 FPV Aerial Photography


Simple structure and light weight,CNC aluminum alloy structure
Brushless motor direct drive
With anti-vibration rubber balls,easy to adjust
Compatible with Gopro 3,2,1
with 2pcs 2208 motors
with latest V2.3B5 firmware gimbal controller, sensor, no need upgrade (SKU: 101101)
with motor protector which can help heat dissipation
230/300gram with/without Gopro hero 3
260 grams with a mobius

GoodLuckBuy gimbal for my mobius camera

I attached my mobius on the edge of the gimbal’s base  and I watched over to balance the camera the best I could. I did that because the less effort the gimbal takes to balance the camera the less energy it wastes to do that.

Goodluck buy gimbal – Mobius – DJI F450OLYMPUS DIGITAL CAMERA

Connections: I connected the pins A0..(see below)

I accidentally connected the gimbal to the wrong pins (although I had read not to connect it to NC pins but I was in a hurry and the numbering on the case was misaligned) and I “burned” my APM (original one). So I had to buy new APM board (a clone one this time see here) and I started again (more carefully this time).


15/11/2015 Update:

For my new Tarot 650 I changed the way that mobius is mounted on the Mobius GoodLuckBuy gimbal and also I created some sort of a base for the gimbal to sit on the downside tubes of the frame.

I tried 2 ways of mounting the mobius on the goodluckbuy gimbal.

I think I will stick with the second way. In order for this to work I had to change the sensor orientation through the SimpleBGC GUI . So I connected the board on my pc and changed the right axis to -Y from -X it was.

I also connected the pitch RC control from the A0 signal pin to channel 6 of my PPM FRSKY D8R receiver and it worked fine. Here are the initial settings where things works fine but needs some fine tuning.

Goodluckbuy gimbal simplebgc settings for mobius

Tarot 650 – PixHawk – Sunnysky X4108S 480kv – 15×5.5 props – Quadcopter setup

After flying the Reptile 550 and the DJI Flamewheel 450 frames I decided to move on with the Tarot 650 frame which will give me the opportunity to try bigger motors and propellers for maximizing the flight duration. This is what I am expecting:

Ecalc Tarot 650 2x4s 5000 batteries, Sunnysky 4108 480kv and Tarot 15z5.5 props

Parts List

The following list contains affiliate links.

Frame: Tarot 650 IronMan

Motors: 4x Sunnysky X4108S 480kv

ESCs :ZTW Spider Series 30A OPTO Multi-Rotor ESC 2~6S (SimonK Firmware) ( I had those from my f450 setup)

Propellers: Tarot 1555 Folding props

Flight controller: Pixhawk PX4 2.4.8 Flight Controller 32 Bit or PixHawk (HKPilot32 – clone)

Telemetry: 3DR telemetry 433 Mhz

GPS: Ublox NEO-M8N

Battery: Turnigy 5000 4s 30C

Radio transmitter: Turnigy 9XR

Radio receiver: FrSky D8R-II PLUS 2.4Ghz 8CH 

Gimbal: 2-axis gimbal for go pro

Cameras: Mobius for video and Canon S100 for photos

Build History

24/3/2015 Tarot 15×5.5 folding propellers are here

Tarot 15×5.5 folding propellers

3/4/2015 Sunnysky X4108S 480kV motors have arrived

20/10/2015 Assembling the Tarot 650 frame and mounting the motors and props

The assembly of the Tarot 650 was pretty easy. I had watched some youtube video guides and had not problem at all. After assembling the main frame I started mounting the motors. Only 3 holes were aligned between motor and mount but that’s enough I guess

23/10/2015 Lengthening ESC’s wires so that they can pass through the tubes and reach frame’s centre

In order to pass the wires through the tubes of Tarot 650 you should lengthen the ESCs’ wires. So after an hour of soldering I was ready to start dealing with the connections.

26/10/2015 Installation of the power distribution board – Connection of APM – RC – GPS etc

I had a problem with the ESCs syncing with the motors. I set the Demag compensation to off and the motor timings to High and the motors worked like a charm.

I flew my tarot 650 yesterday and accomplished flights of 13-14 minutes per battery (1000 mA remained in the battery). Loiter mode was fine. Just some fine tuning needed.


I installed a goodluckbuy gimbal for the mobius camera. You can find here more information about the process.

Mounting mobius on goodluckbuy gimbal 2st way

Flashing Turnigy Plush 25A Silabs ESC with the BLHeli Firmware

29 January 2015

This is how I flashed my Turnigy Plush 25A (Silabs) ESCs with the BLHeli firmware. BLHeli Firmware is the alternative of SimonK to the ESCs with a Silabs chip, and offers higher response of the motors from the stock firmware. It also offers a GUI to program the ESC and lots of features to tweak from.

Required tools/materials/software

  1. Soldering iron
  2. Arduino UNO
  3. Turnigy Plush (Silabs) 25A ESC
  4. Jumper cables (3 for each ESC)
  5. BlHeliSuite


  • Solder the 3 jumper cables to the pins as shown in the following picture. Purple is the C2D and goes to the MISO pin of the ICSP port of Arduino – Green is the C2CK and goes to the MOSI pin and the Red is the Ground.
Flashing a Turnigy Plush 25A ESc with tha BlHeli firmware – Purple is the C2D and goes to the MISO – Green is the C2CK and goes to the MOSI pin and the Red is the Ground.
  • Connect the plugs to the Arduino Uno
image from



  • Connect the Arduino to your computer
  • Connect your lipo to the ESC
  • Download and Start BlHeliSuite.exe
  • Menu “ATMEL/SILABS” -> “SILABS Serial Interface”.
  • Tab “Interfaces for Silabs” will show up. Select the port that the Arduino is connected to.
  • Select “ATMega328P” and click “Make Arduino General”.
  • Select “Arduino_m328P_16_MULTI8v12100.hex” from the new windows.
  • Hopefully the Arduino Firmware is uploaded to the Arduino.
  • Tab “Silabs BESC Setup” Choose the port that the Arduino is on and press connect.
  • Then press Flash BLHeli –> Choose your ESC. I chose the Turnigy Plush 25A Multi hex 12.2 version hex.
  • Now by pressing the “Read setup” you get your ESC’s settings.

After flashing all of the ESCs with the BLHeli firmware I did a throttle calibration through my APM 2.6 and everything worked flawlessly. And the difference from the stock firmware was huge


ZnDiy-BRY APM 2.6 clone compared with the 3D Robotics original one

Today, 3 weeks (which is good!!) after having ordered an APM 2.6 clone from DealExtreme for 39 euros it finally arrived. This clone is manufactured by a company in China named ZnDiy-BRY and it came in a box (!!) including: the APM board in its case and 5 pairs of DuPont signal cables (9cm). So lets’s see the 39 euros ZnDiy-BRY APM 2.6 clone compared with the 3D Robotics original one (120 euros).

  • By comparing them side by side there is a difference in their size but this is only bacause the pins are on the side and not on top like the ZnDiy-BRY’s.
ZnDiy-BRY APM 2.6 side by side with 3DR Robotics’ (with case)
  • Without the case as we can see the two boards are identical except from the placement of the pins.
ZnDiy-BRY APM 2.6 side by side with 3DR Robotics’ without case
  • After weighting the 2 boards with or without their cases I found that there weren’t any differences. So the board without the case weighs 17 grams and with it 32 grams.
  • Someone can easily recognize the cheap plastics (from the case to the dupont clips) but I believe if you treat them gently they will be just fine.

So, I connected the APM 2.6 clone into my computer and I updated the firmware to 3.2, the lights work fluently and it the gyroscopes respond to my moves as expected. The only thing left is to fly with controller and see what happens.

SunnySky X2212 980kV for my light quadcopter (DJI F450)

SunnySky X2212 980kV is the motor I chose for my medium weight quadcopter (Frames:Reptile 550 and then the DJI F450). I found them for 13 euros each from Banggood. They need 2s or 3s batteries to run but after some research I read that they work also on 4s batteries giving more power. I also read that the best propellers you can work on these motors are the APCs 10×4.7 which I bought from TowerHobbies for 4 euros each set (2 propellers – one pusher – one normal).

Sunnysky X2212 kv980 are silent and powerful motors for quadcopters of diagonal length 450-550 and with total weight of about 1400 grams. They weigh 56g each. With a 3s battery and 10×4.7 propellers they give maximum thrust of 870 g which lifts easily a 1400+ quadcopter. I have tested them with a AUW of 2100 grams and it started ascending at a throttle of 60% and hover at 66%. It was underpowered but it flew.

Some people are complaining about the motor’s bearings failing sometimes. For that reason I have purchased some bearings and clips to have spare and change when needed (after a major crash). Here is a video showing you how to change the bearings. It’s not the most professional video out there and it have mistakes but it gives you something to start with.

Scorpio bearing oil

Bearings R2zz and R2-5zz from

Traxxas E-Clips/ C-Rings Z-TRX1633

How to connect Mobius camera – Boscam FPV – MinimOSD (noise problems, solution)

This is how I connected a Mobius ActionCAM , a MinimOSD and a Boscam FPV 5.8G 400mW AV Transmitter Module TS353 to get picture on a FEELWORLD FPV-769A 7″ HD 800x480p FPV Monitor through a Boscam FPV 5.8G 400mW AV Receiver RC805.

1. Connecting Mobius camera and Boscam TX

First of all I connected the mobius camera to the Boscam TX to check everything was fine.

The orange wire from mobius camera (video out) goes to pin 5 (pic 2) of boscam TX (video in) and

The brown (and then black) wire from mobius camera (ground) goes to pin 7  of boscam TX.

I didn ‘t use the audio out wire from the mobius camera as the boscam tx already has a mic.

To the  pins 1 and 2 of the boscam tx I connected the + and of the 3s battery. Read More

F450 – APM 2.6 – Sunnysky 2212 980kv – 11×4.7 props – Quadcopter setup

Welcome to my F450 Quadcopter Diary. This is my small quadcopter. I will be using it mostly for taking aerial images using my 2 Canons: A2200 and A490 (IR converted). In this diary I will be recording anything that would possibly help anybody with or without the same setup. As I have already mentioned in a previous post, I replaced my Reptile 550 frame with a DJI F450 Flame Wheel one, mostly to gain some flight time from the weight reduction and to reduce (I hope) vibrations caused by the cheap Reptile 550. Read More