After a quick ride through Tiergarten today, here are the first results. As a last minute alteration, I’d nailed elastic strips to the swinging drawing platform to hold the paper and attached a bit of metal to the arm to make the pen lighter and less friction on the paper.
Strapping the machine to the bike rack, I was ready for the off:
Problem number 1:
In the quiet of my living room, I’d never anticipated how much bike racks jump up and down and thought that having the cables guided by the terminal block findings was adequate. Arriving at Tierpark after a moderate amount of kerb-mounting (nothing out of the ordinary), I found that the cables had jumped right out of the guides and fallen right down the armature.
These are the results. In the first drawing, you can see there are two areas of concentration, showing that the cables must have come out of their guides quite early on as the off-centre area is quite full.
In drawing two, you can see a smiling shape emerging as the forces on the bike are mostly lateral rather than accelleration/decelleration and tend towards the middle. There is a flattening at the top of the drawing due to the tray not moving back as the post for the pen holder stops it.
I made drawing 1 on the way to the Tiergarten and drawing 2 round the Tiergarten. I loaded the paper again for the way back but then Problem 2 struck: The paper blew away (or fell victim to the magic of the Celtic year change as the cross-quarter day of Samhain falls soon and there should be faeries and spirits about).
This made me think about Solution 1: solder some rings to the underside of the terminal block findings and run the cables through these.
Solution 2: buy a thick-ish piece of steel to replace the wooden drawing platform and use some rare-earth magnets (have lots here and in the studio) to hold the paper in place. This will also help add weight to the drawing platform which I feel needs a bit more.