Lesotho will soon fall under a sustained but welcome surveillance from the skies above; a surveillance by drones being developed at the National University of Lesotho (NUL)! Your weddings, graduation ceremonies and social rallies will also be pictured from the heavens above, thanks to this amazing technology!
Many people associate drones with Obama who uses them to kill and maim suspected terrorists in the remote regions of Pakistan. Mr Thabo Koetje and Mr Seforo Mohlalisi, both lecturers at the NUL Department of Physics and Electronics, are working to use these objects for opposite and peaceful purposes; Aerial Photography and Surveillance.
Drones are basically unmanned aerial vehicles. Normal airplanes have pilots. Drones are controlled from the ground. However, Mr Koetje and Mr Mohlalisi will use far smaller drones, good enough for the said purpose.
“Our model is simple, we start with existing toy drones,” Said Mr Koetjoe. “These toys are usually meant to entertain children! We are using them for a more lucrative ideal. The problem with the toy drones is that they are hard to control. The altitude (height) and geographical position they reach are controlled by pressing the toys’ hand-held controller’s buttons. Thus the drone’s movements and height are completely depended on the position of the pressing fingers. We are engineering a better control of these toys to suit our purpose.”
First the team dismantles the existing drone toys so that they can modify them from within. The main goal is to control both the height that the drone can take and its position relative to the ground by using a cell-phone application or a computer. “The drone toys are notoriously disobedient, which is entertaining to children, so our role is to “teach” them disciple,” Mr Koetje explained.
That is a tricky task! First the innovators throw away a control system that comes with the drone and install their own. Their operation is based on the basic understanding that drones height depend on the speed of its blades. The direction in which drones move depends on some of the blades moving a little faster than others.
Therein lays the secret. “If we can control the speeds of the blades, we can control how far up, the drone can go and which position relative to the round it can take, right on our cellphone or computer screen, with no hand-held devices,” added Mr Mohlalisi.
And this is how they do it. First, they mount a circuit which they have built themselves on the drone. The circuit is meant to control the speed of the blades. By controlling the speed it also controls the position relative to the ground as it can be made to let different blades assume different speeds. However, the circuit doesn’t work alone.
“The circuit is assisted by Wi-Fi and Bluetooth modules,” Mr koetje said. “So far we have installed only the Wi-Fi module. These two do the same work. So if one module stops working for some reason, we can depend on the operation of the other. We don’t wan’t the drones falling on people!”
The Wi-Fi and Bluetooth modules help to communicate with the cellphone application or the computer on the ground. The only limitations with the Bluetooth will be a smaller range of application, which is around 10-15 m. The Wi-Fi is better, with a range of around 100m to 150m or so.
The biggest question would be; how would they keep the drone to the altitude (height) they want? “This is where we apply the principles of process control,” the innovators said. “As far as altitude control is concerned, we depend on two systems. We use a combination of an ultrasonic altitude sensor and a Global Positioning System (GPS).”
The former is more accurate in terms of sensing altitude but is limited to the operations of about 5 m above ground. The latter is less accurate but handles very long ranges above the ground. Thus we use the former to ensure that our drone doesn’t fall accidentally on any object on the ground. If the drone detects unexpected height beyond that to which it is programmed to land, it will not land. Beyond 5 m or so, the GPS system will ensure that the drone stays at the height it is meant to be.
So far, they have tested the height control and it works very well. They can put the drone to any altitude they need using a computer and they are developing a cellphone app to do the job. They also are awaiting another version of a drone toy with better blades to control position relative to the ground.
The applications for this technology are many. However, Mr Koetje and Mr Mohlalisi would like to use the drones mainly in taking aerial pictures and videos of events. “The drones can spend up to four hours in the air, and we can bring them down to change their rechargeable batteries,” They said.
They concluded by saying that they envisaged a system in which they were going to mount a camera in these drones and take aerial pictures and videos of weddings and graduation ceremonies to mention a few events. “Such aerial shots are beautiful and rare. In contrast, videos and pictures taken from the ground miss a lot of information about any event due to a plenty of physical impediments among us, the earthlings,” they said. “Drones, being airborne, have little to no impediments, as they float in the “heavens” above.”
This blog post was originally written by NUL Research and Innovations