User manual

Science Manual – Using Video Images for Fisheries Monitoring 63
Appendix 9: How to make your
own underwater light panel
By: Mike Haley, MEICA Team, Crosshands, Wales.
Components (supplier)
Perspex case (Westward Plastics)
PX449 12-volt red LED strips (Plus Opto)
Potting compound such as Ambersil Q-SIL 215 (Farnell, RS)
Stainless steel screws
Silicone sealant – marine grade
Waterproof glands
Rubber matting
The light panel illustrated here has the following dimensions:
Outside = 661 x 1501 x 30 mm
Inside = 640 x 1484 x 20 mm
This gives an internal volume of 0.19 cubic metres, requiring almost 19 kilograms of
potting compound.
Warning: The polymers used here will absorb water over time. This may cause
water ingress to the electronics, eventually leading to failure. The mean time before
failure has not been estimated but if a light panel is required for several years,
consideration should be made for making the tray out of metal and for provision for
the diffuser lid to be changed annually.
Preparation
1. Send drawing with required light panel dimensions to Westward plastics: Contact
Mark Britton (0117 935 8058). Opaque diffuser and solid white tray.
2. Attach rubber matting to the outside of the base of the light panel.
3. Contact MEICA electrician to attach red LED strips (from Plus Opto, 01942
671122) to the base of the tray, wire them up and seal gland in place.
4. Put box on level surface, pour in well mixed and vented potting compound.
Replace diffuser, refasten all bar three screws to allow expansion of compound
(see datasheets for use and health and safety).