Computer scientists create electrified ‘dandy horse’
Image credit: Felix Freiberger
Two centuries after its first test run, German computer scientists based at Saarland University have recreated the ‘dandy horse’, electrified and equipped with video camera and sensor for safety.
The dandy horse – the forerunner of the bicycle – was first taken for a test run in 1817 by its inventor, Karl von Drais. The simple vehicle has two wheels in a line like a bicycle, but is propelled by the rider walking or running along the ground with the dandy horse between their legs.
Modernised dandy horses are used as starter bicycles for children to learn balance, but the Saarbrücken-based team hope that their electric dandy horse could be appealing to adults as well.
The team is led by Professor Holger Hermanns, a Saarland University computer scientist and bicycle enthusiast. He hit headlines in 2011 with the creation of a wireless bicycle brake, and wants to use his research to help the e-bicycle industry avoid programming errors and improve operational safety.
Knowing that June 2017 marks 200 years since the first bicycle tour, Professor Hermanns decided to replicate and modernise the dandy horse with an electric drive. The prototype, the Draisine 200.0, is made almost entirely from wood, including the wheels. It contains a battery, motor, sensors and small computer.
The rider can brake by pushing on a foot pedal on the front wheel. A 200W motor is powered by a 0.75kg battery installed in the back wheel. A Raspberry Pi and speed sensor controls the motor.
When the rider pushes off from the ground, the motor jumps into action to provide extra power, much like a conventional electric bicycle. While the motors of other electric bicycles switch on when the pedals move, the dandy horse has no pedals. Reliably working out when the rider wants to move has proved a challenge, with potentially serious consequences if errors are made.
“Imagine that you jump over a curb, the sensors interpret this as pushing and the electric motor speeds up to its 25 km/h top speed,” said Professor Hermanns.
To improve safety, the team added a camera to the frame, and to synchronise the video with the sensor data, added an LED clock to be read automatically. By the time they had created their third prototype, the machinery could be hidden within the wooden frame, and the electric dandy horse is no longer affected by strong vibrations.
Once Professor Hermanns and his colleagues have proven mathematically that the motor can be prevented from overrunning and overloading the battery, they plan to take the electric dandy horse for a longer test ride.