I have this thing; it has a control panel on the top surface, so if it
rains the switches etc will get wet. I've made a hinged cover from
perspex. That's fine, except that when it's open it can fall back and
might get damaged. The perspex cover is 400 on the hinge side by 125mm.
Below the cover the control panel is only 35mm down. So there isn't much
room for any sort of sliding arm that would limit how far the lid can
open. I was wondering about some sort of miniature chain. Does anyone
have any experience of this problem, or know where I could buy a chain
with fittings, or can think of any other solution?

Bill