In the next segment please pay no attention to the noisy men with the horns. About 30 sec. in to the video you will see a modern high tech version of the H. G. played by a woman at a Festival in England. She kindly explains how the instrument works and opens it up for you so you can see the wheel and how the buttons work. Like many Indian instruments the Hurdy Gurdy gets it unique sound from built in resonating strings making it sound like a bag pipe with drones.
In French, this man seems to explain his modern design improvements on the H.G. This one appears to run on electricity so you don't have to crank it if you don't want to. It has a nob for changing the speed instead. The French must take their Hurdy Gurdies very seriously. This instrument seems to have many adjustments which make it possible to play in many keys.
You can see the Hurdy Gurdy played in this one about 7 minutes into the recording. You also get to see other bowed instruments which were contemporary with the H.G. These instruments were popular with various cultures all around the Mediterranean Sea at a time when knowledge about the arts and sciences was spreading from the Middle East and South Asia. Merchants and traders brought with them many of the first bowed instruments from the Silk Roads.
Hurdy Gurdies made it all the way to Ireland 1st and then many places in Europe. Since the model he has is much simpler in design musicians had to create all their melodies in modes. It would be like creating all of your scales and melodies using only the white notes on the piano. Other instruments and voices could play the additional notes in the melody while the H. G. played the basic chords for the accompaniment. More modern instruments with more buttons and levers allowed the Hurdy Gurdy to play more keys and melodies.