Auto-Sifters: money while you dig

What they do

Each machine sits at a spot around the haystack and drives a tunnel into it, working in several directions and in layers as it goes. About 1.6 times every second it digs a scoop of hay. Whatever valuables it uncovers it sells for you automatically, so the money arrives while you are busy somewhere else. If one of them digs up the needle, you get a message and a beam of light shines above its tray.

Prices

You can have up to six. Each one costs 1.7 times as much as the one before it, rounded to the nearest $50:

When to buy them

One machine is a good first big purchase, usually once you have the Pitchfork and a detector. It starts paying back immediately and keeps going while you are away from the keyboard in the game. Later machines cost much more, so weigh each one against a bigger tool: sometimes the Hay Vacuum 3000 or Detector Mk III will help you more than the fourth machine. See Best upgrade order.

Getting the most from them

• Dig somewhere else. The machines start from the outside of the stack and tunnel inward. Dig your own tunnels in other parts so you do not cover the same ground twice.
• Look for the beam. If a machine finds the needle, a pillar of light marks its tray. Run over and grab it.
• Remember they restart. When you find the needle and start a new stack, your machines stay but begin their tunnels again from scratch.