LED strip light for moth trap

There are many options for buying or making an LED light for a moth trap. Here is an approach we use for the budget bucket moth trap used in our Introduction to Moth Trapping workshops.

Components:

LED strip

Purchased through online sellers on Amazon, eBay etc. There are various power options of these UV 'colour' LED strips. They are available with either 150 or 300 LEDs per metre and either 3528 (3.5mm x 2.8mm) or 5050 (5.0mm x 5.0mm) LEDs. The quality varies considerably it seems with some the percentage UV output is quite low and for others the phosphor use to convert to UV 'wears out' very quickly. So, do test them for 12 or 24 hours. We have found the 150 x 5050 LEDs most reliable and have used the silicon covered waterproof variety.

We also found that their power depends on the (quality and voltage of the) 12v battery used. The power appears rarely gets above 50% of the quoted figures. We cut down 5m strips into 2, 3 or 4 equal lengths depending on the power required and also the capacity of battery to be employed. Some have connectors, so choose one of these if you aren't into soldering and using adhesive lined heat shrink tubing.

Power cable

A 1.5 metre cable is normally about right to  reach to the battery.

The cable end connections are entirely dependent on the type of battery. The LED strip connectors end often require 2.1mm/5mm male jack plugs, but they can vary. 

Batteries can have the same jack plugs or may need crocodile clips. Hunting around on eBay will usually reveal something with the required end connectors.

USB power converter

The LED strips work at 12 volts. For up to about 10 watt LED strips (1m) a USB 5v to 12v converter can be used.

Note: this will only work in combination with a light sensitive switch if your 5v USB power bank has a feature not to turn off when not drawing a current.

LED strip mount

The LED strips should be self-adhesive and can be mounted on something like a water bottle or plumbing pipe. We use 68mm uPVC downpipe.

Mounting bar

We use a length of 30mm uPVC architrave to which the LED strip mount pipe is attached. What is best will depend on your trap.

Trap attachment

We use 30mm wide self-adhesive Velcro stuck to the mounting bar and the top of the trap, but have used self-tapping screws and wing nuts if something more robust is required.

Cable zip ties

Used to secure the ends of the LED strips to the Tube and the Tube to the Mounting bar

Alternative attachments

Self tapping screws or wing nuts can be used if required.

Light sensitive switch

These are very useful to enable traps to be set up before dark and to reduce the drain on the battery in the morning. Quite straight-forward to add to the 12v power cable with a little wiring skill.

Assembly

Cut LED strip to length

Kitchen scissors can be used to cut the LED strip. The cut needs to be through or next to the copper connectors between every third LED (as the LEDs work in sets of three).

The length depends on the power that you want or or importantly the capacity of your battery. As a rule of thumb we suggest 1 metre for every 10ah of battery capacity, but there are many variables including the power of the actual strip and the length of night that the trap needs to run for.

We add a glue lined heat shrink tube to the end in order to provide something for a cable tie to hold down to ensure the strip is kept in place.

Attach strip to tube

First do a trial wrap of the strip around your tube or bottle to make sure it fits or to work out how long a length of tube (or size of bottle) that you need.

Leave at least 10mm margin free at the end of the tube or bottle. Then drill or hot panel pin pierce the tube with two small holes (about 2.5mm) about 5-10mm apart where the LED strip will start. This will allow a cable tie to be fed through and hold the heat shrink at the end of the strip securely in place.

Remove the strip's self adhesive cover as you then carefully wrap the strip around the tube. Just before you get to the end, drill or hot pierce the tube in the right spot to allow a cable tie to secure the end.

Attach tube to Mounting bar

Drill holes in the margin of tube that you left previously at opposite sides of the tube.

Drill holes in the mounting bar appropriate to the diameter of the tube.

Use cable ties to attach the tube to the bar.

Mount on your trap

Cut and affix the Velcro to the bar and the lid of the trap.

Optionally drill through the bar and top of the trap and use self-tapping screws or bolts and wing nuts.

Trap with USB 5v power Showing USB powered with 5v to 12 converter and light sensitive switch with 10w LED strip light.

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