Cold frame with electronic thermostat?

[davee52uk]

In "Allotment Days" by Matthew Biggs there is a bloke who has made a cold frame with electronic control over the glass. This uses solar power to raise or lower the glass when it is gets too hot.

He also seems to have moulded concrete to make a stackable compsot heap where the concrete formes fit over each other and an insulated compost heap - amazing.