I have just dug my wife's old bike out of the back of the shed and given it a bit of a service, as my step daughter wants to cycle around a bit. There is this trip computer attached to it which has no apparent markings other than those in the photos. It appears to rely on a sensor on the front wheel to operate, and much to my surprise when I put a new battery in it it sprang into life and recorded my speed and distance (in km) as I rode it up and down the close. It is obviously very olde school and I would be grateful if somebody could tell me it's origin or more importantly how to drive it. I can scroll through using the buttons but I can't even turn it off at the moment.
Thanks in advance.