ConservationDrones.org has been collaborating with Remo Peduzzi, Simon Wunderlin and Sämi Pulfer from ResearchDrones.com to develop the next generation of drones for conservation applications. Remo, Simon and Sämi bring with them expert knowledge on the building and configuration of UAVs.
Conservation Drones 3.0 (MAJA Edition)
For our latest drone model, we adapt the Bormatec-MAJA airframe, designed by a German company specifically for UAV use.
You may download a copy of the APM parameters file for the MAJA drone here.
Although this airframe is more expensive than previous models of Conservation Drones, the MAJA has several unique features that are well worth its cost. For one, the top half of the entire length of MAJA’s fuselage fully opens like a hatch to expose a huge storage area, allowing easy installation, access and manipulation of onboard equipment in the field, including the autopilot, batteries and camera.
The MAJA airframe itself weighs about 2.0 kg (including ~900 g of batteries), and can carry a payload of another 1.0 kg! This essentially allows the MAJA to carry both video and still-photo cameras!
The MAJA drone can be fitted with either 1.8 m or 2.2 m wings, depending on payload and range requirements. Our test model was fitted with the latest autopilot system from 3DRobotics (APM 2.5), an external GPS module, all metal-gear servos, telemetry and two 5000 mAh battery.
However, what has gotten us most excited about the MAJA is that, due to its superb flight characteristics the MAJA drone can perform fully autonomous landing within a 100 x 100 m landing area.
Unlike previous models of Conservation Drones, the MAJA edition is fully loaded with high quality materials with no expenses spared. The reason for doing so is that after having flown our Conservation Drones across various deployment sites in Asia and Africa and upon feedback from colleagues, we decided that in the long run, it makes more economical sense to invest in higher quality build materials to ensure more reliable and longer lasting drone units.
One unit of Conservation Drones MAJA Edition is currently being tested in the field by Sander van Andel in Gabon. Several units of MAJA are being assembled for other colleagues in Nepal, Kenya, Malaysia and Indonesia.
Conservation Drone XX: Next generation drones under testing
We continue to experiment with several different airframes for Conservation Drones. There clearly is no one-size-fits-all solution. And there is a stark tradeoff between portability/size and long-distance capability. One of these models is the X5 which we mentioned earlier. Another promising candidate is the new Condor Skywalker 1880. The main motivation to experiment with the Skywalker is to improve flying time and range. The main advantage of the Skywalker over the FPV Raptor (Drone 2.0) and HK Bixler (Drone 1.0) is that the Skywalker has massive fuselage and wing area. Furthermore, a side door can be cut out from the fuselage to facilitate initialization of the APM and camera prior to each flight.
An initial test using two 3S 20C 4000 mAh batteries connected in parallel (8000 mAh total), with an additional dummy weight of 200 g (simulating a GoPro camera payload) suggests a total flight time of ~70 min. That test flight was achieved with a Turnigy D3536/8 1000 KV motor spinning a TGS 9x6E propeller, regulated by a 50A speed controller, and had an All-Up-Weight (AUW) of 2.2 kg (~900 g of payload). If programmed to fly at a speed of 12 m/s, the total range of the Skywalker-based Conservation Drone would be close to 50 km!
You may download a copy of the APM parameters file for the Skywalker drone here.
Conservation Drone 2.0: The Flying Fortress
Conservation Drone 2.0 is based on another popular remote control model plane, known as the FPV Raptor, which has a 2 meter wingspan (Drone 1.0 had a 1.4 meter wingspan). We equip this drone with a much bigger 5000 mAh battery pack, which gave it a longer flight time of up to ~50 minutes. When programmed to fly at a speed of ~10 m/s, the drone can cover a total distance of almost 30 km.
You may download a copy of the APM parameters file for the Raptor drone here.
Conservation Drone 1.0: The Prototype
We based our prototype drone on a popular model airplane (Hobbyking Bixler). This airplane is relatively inexpensive (<;$100), lightweight (~650g), and has ample room within its fuselage for installing the APM and an onboard camera. During our field tests, the drone was powered by a 2200 mAh (milliampere-hour) battery, which allowed it to fly for ~25 minutes per mission, and over a total distance of ~15 km.
You may download a copy of the APM parameters file for the Bixler drone here.
The APM unit is housed within a customized chassis, which in turn sits in the canopy opening of the plane’s fuselage.
An opening was cut out from the floor of the fuselage to allow the lens of a Canon IXUS220HS camera to extend downwards.
The autopilot system of Conservation Drones is based on the ‘ArduPilot Mega’ (APM) autopilot system, which is being developed by an online community (diydrones.com).
The APM includes a computer processor, geographic positioning system (GPS), data logger, pressure and temperature sensor, airspeed sensor, triple-axis gyro, and accelerometer. By combining the APM with an open-source mission planner software (APM Planner), most remote control model airplanes could be converted to an autonomous drone.
For detailed instructions on the assembly of the APM and other electronics, please refer to the Ardupilot Wiki website.
It is important to understand that each airframe requires a customized configuration file (containing PID parameters) to be loaded onto the APM. These configuration files for Conservation Drones are available here: Conservation Drone 1.0 (Hobbyking Bixler), Conservation Drone 2.0 (FPV Raptor 2m), Conservation Drone Skywalker Edition and Conservation Drone MAJA Edition.
Detailed instructions on how to connect the APM unit to your radio receiver and control servos are available on the Ardupilot Wiki website.
This configuration file for programming the Hobbyking 6-channel transmitter, when used together with this APM configuration file, will allow for four flight modes of ‘Manual’, ‘Stabilize’, ‘Auto’ and ‘Return-to-launch’ for Conservation Drone 2.0 (FPV Raptor 2m).
Still photograph camera
Conservation Drones have been equipped with a Canon Powershot SX230 HS or Canon IXUS 220 HS camera. The SX230 HS has a built-in GPS. We replaced the original firmware of these Canon cameras with a Canon Hack Development Kit (chdk.wikia.com). This ‘hacked’ firmware allows us to implement a customized intervalometer script (click to download) to command the camera to take photographs at user-specified time intervals (e.g., every 3 seconds). This script also allows the user to define several other parameters including: i) time-delay before the camera begins taking pictures, ii) focal length of camera lens, and iii) time before camera automatically shuts down and retracts its lens. We suggest the following settings in the camera’s menu:
GPS Settings (camera’s ‘native’ menu)
GPS Logger: OFF
GPS-Settings (CHDK menu)
To compensate for movement of the drone in flight, we recommend setting the camera for ‘shutter priority’ (Tv) and at a speed of > f 1/1000. Under this setting, our test photographs effectively avoided motion blur.
Documentation of camera set-up by Dronemapper.com:
- Detailed CHDK firmware installation instructions (Link)
- Detailed graphical instructions on optimal CHDK settings (Link)
- Guidelines on aerial data collection and flight planning (Link)
During flight, the electric motor of the drone does produce vibrations which could result in vibration blur in photographs. As a solution, we created a vibration dampening system using low density packing foam. We later discovered that the common kitchen sponge works equally well as a construction material. This instrument for Stable Placement of ONboard Gear and Equipment (iSPONGE) successfully removes vibration blur.
The iSPONGE requires only a single kitchen sponge (~85 X 70 X 35 mm), some pieces of non-adhesive velcro straps and a strong glue (e.g. Gorilla glue).
1. First cut hole for lens (~45 mm diameter for Canon IXUS 220 HS)
2. Stick velcro straps to sponge at appropriate spots with strong glue.
3. Hot-glue edges of long sides to fuselage.
How it works: the camera (~140 g) sits on the sponge, and together they jiggle like jell-o (or jelly). This dampens vibration from the motor really well.
The Conservation Drone can also be equipped with a video camera. We used a GoPro HD Hero2 camera housed within a protective shockproof casing. This camera was attached to the belly of the plane and pointed at ~45 degrees forwards and downwards. During our test flights, all video footages were taken at a resolution of 1080 x 720 pixels and at 60 frames per second.
We have also used a ContourGPS video camera, which gives similar results as the GoPro. However, the ContourGPS does allow for video mapping using its built-in GPS.
Anti-vibration solutions for quadcopter
Even having taken all necessary precautions and running the required pre-flight checks, there always remains a chance that unforeseen circumstances (e.g. mechanical failure, sudden weather changes) might cause a drone to be lost in the field (we strongly advise against flying a drone in urban, populated areas for this reason).
To help locate and recover the drone in a forest, for example, we suggest adding a GPS Tracker in its payload. A good and cheap example is the ‘Handheld Portable Mini GSM/GPRS/GPS Vehicle Tracker‘, which weighs only about 65 g. It requires a SIM card (GSM 850/900/1800/1900) to work, and can SMS (text message) the coordinates of its location to your mobile phone at set intervals. (*We are not financially sponsored by the manufacturer or distributor of this product. We are merely suggesting an example we have tried and feel that it works well for our purpose.)
We have made several other modifications to the FPV Raptor airframe (Conservation Drone 2.0) to improve its performance and operation in the field.
‘G-Chute’ – Parachute Deployment System
The main constraint of operating the drone in a tropical rainforest is the lack of landing space. We are in the process of developing a parachute landing system. This gurney parachute system is an early prototype.
Disclaimer: The Conservation Drones team (Lian Pin Koh and Serge Wich) strives to develop Conservation Drones that are operationally stable and safe. However, we have no control over the operation of Conservation Drones by our collaborators. And therefore, the Conservation Drones Team will be not held liable for any bodily harm and/or property damage resulting from the operation of Conservation Drones by third parties, including our collaborators.