Weather Station Rain Gauge Bird Spikes

It's important to keep bird droppings from getting into the rain collection funnel of your weather station, so bird spikes are an important addition.  This spike ring is designed to fit funnels that have a 118mm outside diameter, which includes a number of popular models.

It has a tapered top edge to avoid collecting any additional rain drops or splashes which could affect the measurement accuracy.

I printed this in nylon on a Formlabs Fuse 1 SLS printer, but other materials that will stand up to the weather can be used as well.

Hardware:

• (1) M3 nut (5.5mm across the flats, 2.5mm thick)
• (1) M3 x 12mm (or longer) bolt
• (12) 25cm pieces (3m total length) of galvanized or stainless steel wire, 1.5-2mm in diameter (15-18 gauge)
• (optional) Electrical tape or similar for grip

Assembly:

1. Straighten coiled wire and cut into 25cm lengths using wire cutters. Make the cuts at an angle to add as sharp of a point to the ends as possible.   The exact length is not critical.
2. Bend each piece in half, keeping the bend fairly sharp. Again, it's not critical that they be bent exactly in half, just close.
3. Insert the M3 nut into its slot on bottom side of the spike ring until it lines up with the bolt hole.  Insert the M3 bolt a few turns into the nut (so neither falls out while handling).
4. Insert each bent piece into a pair of spike holes from the bottom side of the ring. The bend should end up hidden inside the ring.
5. Bend each leg away from each other to angle one half slightly inwards, and the other half outwards. This will secure the spikes and prevent them from falling out. Alternatively, you can leave the inner spike sticking straight up, and only bend the outside spike outwards (if you're concerned about the miniscule amount of water that may be deflected by the inwards-facing spikes).
6. If desired, place one or two layers of electrical tape around the outside rim of the rain gauge funnel to provide better grip/fit when clamping the spike ring onto it.
7. Place spike ring on the top lip of the rain gauge and tighten the bolt until the ring grips snuggly (don't over tighten).