Electronic Open Door Alarm (for fridges and freezers)

I am looking to manufacture a fridge freezer door alarm. The idea is to protect against leaving your fridge door open by accident. It should sound an alarm if the door is left open for longer than 30secs. I don't want it to detect the state of the door by sensing the interior light but rather by using a magnetic reed switch similar to those found on doors in burgalar alarms. The circuit should have an aditional connector to allow the door to be automatically shut by an electromagnet (optional). The product should be powered by batteries if at all possible. I require full schematic drawings, circuit board design and a full list of componant parts, their values and partnumbers as well as possible suppliers (preferablly in the UK). I would also be interested in anybody who would be prepared to manufacture this (in the UK or out), so long as you can provide a very low quantitiy first run for testing purposes. ## Deliverables 1)Complete Schematic with notes and description of functionality. 2)Complete parts list including values, part numbers and supplier details. 2) Completed and labelled Circuit board design - fully labelled and space optimised. 3) Suggested enclosure with part number and supplier details ## Platform DC voltage