How does the Dowsing Machine in HeartGold/SoulSilver work?

Question

I hate this Dowsing Machine because for me it functions weird and looks complicated. Are you supposed to walk forward when it starts getting orange?

Answer 1

When you have it on, make sure you have a stylus or your fingers on the Touch Screen at all times because that's how it works.

At first, you'll be hearing a continuous low ringing sound as you keep your fingers / stylus on the Touch Screen.
If the ringing slowly becomes louder and faster, you'll notice the machine screen starts slowly glowing. This means items are nearby.
As you get closer to the items, the screen glows even brighter, to the point of very bright yellow and the ringing is faster.

You'll eventually see dots / circles on the map as this happens, so plan your movements accordingly to what the machine displays.
If the dots / circles are in the middle of the machine (or very close to the middle), it means you are in front of the items and you can pick it up by pressing A.

Hope I helped! Source

Answer 2

Not really, in fact.

Use the touch screen to pinpoint the location of the item. The brighter orange it is, the closer you are to the item. To get to the item, walk to where the item is located. The machine is positioned in respect to you:

Going up 5 and right 1 and pressing A will net you the item.