Geiger Counter

The Geiger Counter is a ship part of the S.S. Dolphin in Pikmin, on The Forest of Hope. Although the part is vital to the ship's repair, Captain Olimar is ignorant as to what its purpose is. He notes it "goes wild and lets out a lot of noise", but he ignores it regardless and admits he should read the operator's manual for it.

The Geiger Counter reappears as a ship part in Olimar's Shipwreck Tale in. It is found in the Hero's Hideaway.

After being collected, this part is installed on the ship's main hatch.

In Pikmin
From the landing site, go to the right. Break a wall with bomb-rocks that's to the left of the Yellow Onion's original position. Defeat a few Spotty Bulborbs and Dwarf Bulborbs and then use Blue Pikmin to push a cardboard box near the water, allowing him to progress further. Olimar will then find three Burrowing Snagrets; mainly attack the Snagret closest to the edge as it has the ship part, but be wary of the two neighboring Snagrets. The Whimsical Radar is useful to distinguish the right one. It should be noted that the Snagrets will continue to attack the Pikmin carrying the ship part, so all Snagrets should be defeated to ensure Pikmin safety. If you fear for your Pikmin's safety while carrying the Geiger Counter back to the Dolphin, have Blues carry it, as they are immune to drowning and can bypass the Snagrets by carrying it off the edge of the cliff, through the pond underneath and onto land.

In Pikmin 4
Dig a tunnel to the kitchen countertop in the western part of the area. From there, go past the sink on the right (or swim over it if you are using Moss). Break down the electric gate using Yellow Pikmin and proceed right, where you will find a Bearded Amprat and a stack of two saucers with the Geiger Counter on top. Killing the Amprat is recommended to ensure the Pikmin's safety as they carry the part.

Trivia

 * In real life, a is a device used to measure radioactivity in a given area. The clicks and buzzes Olimar mentions is the Geiger Counter reading the amount of radiation. The faster the rate of clicks and buzzes means there's more radiation in the local area.