Ernst Pretorius, an engineer and MD of PRAESIDIUM ELETROTEGNIEK from Pretoria may well have invented a device that could have saved the now famous Cecil the lion’s life.

“I can say my invention sprung to life two years ago after a conversation with a farmer friend of mine who was distressed about the ongoing pillaging of the animals on his farm,” says Pretorius - a great lover of animals and wildlife.

The unique device, which has seen several iterations since Pretorius first came up with the idea, is fondly known as the DRAADSITTER (Afrikaans for fence sitter).

Not only has DRAADSITTER received an international award from the Royal Academy of Engineering but the invention is so ingenious that it was selected by South Africa’s largest private rhino farmer to secure the perimeter of his farm.  The DRAADSITTER has also grabbed the attention of South Africa’s farming community. Pretorius’ company, PRAESIDIUM ELETROTEGNIEK, will also be rolling out DRAADSITTER abroad.

Patent attorneys Adams & Adams’ associate, Wynand Fourie has been instrumental in ensuring that Pretorius’ brainchild is protected.

“In October 2012, Ernst contacted me and enquired about protecting a concept for monitoring a cable which he demonstrated to me using a fairly primitive circuit developed on breadboard” (a board for making an experimental model of an electric circuit), says Wynand.  The first step according to Wynand was to establish whether the invention was in fact new by conducting a patent novelty search. “The first question is always whether or not the invention is new and thankfully in this case Ernst approached me first before making the DRAADSITTER publicly available. In a case like this where a product is so saleable and has the potential to make such a social impact, it is imperative to get protection as soon as possible. I then conducted a patent search, following which we filed an international Patent Cooperation Treaty (PCT) application. Upon maturity of the PCT patent application I assisted Ernst in lodging patent applications in 58 countries around the world.”

No bigger than the size of your hand, DRAADSITTER is designed wirelessly to monitor a fence and to detect and report where and when an intrusion has taken place, a fence has been cut, or an attempt has been made to breach a perimeter of the fence.

A number of DRAADSITTER mounted to fence posts located 100 to 200 metres apart form an impenetrable security system.  These units communicate with each other remotely.  Attempted break-ins are then reported to a mobile device or dedicated site.

DRAADSITTER has two modes of operation, a sensitive mode in which it measures and detects acoustic signals conveyed along the fence wire as a result of a physical disturbance of the fence and a second less sensitive mode for detecting when a wire is cut. Furthermore, the DRAADSITTER suppresses noise by cancelling out any ambient noise hence increasing sensitivity of the DRAADSITTER.

Each DRAADSITTER unit runs using two AA batteries and has an exceptionally long battery lifespan of over a year.

DRAADSITTER detects and reports veldt fires, can withstand lightning and can be used on electric fences as well as conventional fences. DRAADSITTER also sends the user a notification if the voltage level of the batteries has dropped below a threshold so that they can be timeously replaced.

“I am so delighted that DRAADSITTER is beginning to have an impact on the protection of our endangered wildlife.  As a lifelong lover of animals, it is so heart-warming to know that my invention may just be the reason future generations are able to enjoy the creatures we are so desperate to save.”

Contact: Ernst Pretorius, inventor
Wynand Fourie, patent attorney, Adams & Adams