Initial sketches displaying a bike lock which fits under a bike seat utilising the two seat supports. 
From my initial sketches i went on to develop and make a works like model, achieving this through the use of a laser cutter and some simple wiring using LEDS. I was pleased with the outcome, however I noticed two problems with the design; placing the lock under the seat required being able to slide it straight under but this was difficult without looking and the LEDS didnt let off as much light as they could, being within the ellipse and so would be hard to see the lights sideways on, whereas if they were on the edge of the lock the light would come out of the side and straight on. 
As a result, I made the lock so there is a bar that stays under the seat and the body of the lock clips onto this,  I decided to remove the ellipse and create a shape which fits the form of the lock better and will therefore let the light out more effectively. 
My design is effective and creates a new place for a lock to be kept when cycling, changes I would make to the design would be to ensure the lock cannot be felt under the buttocks as with the bike I tested the lock on it was felt, but noticed this was due to the very thin nature of the seat so instead of this adjustment a slight change in the form and size of the lock could help prevent this.