Scrap Mechanic: How to Build the Best Farm Defense Setup

Crops in Scrap Mechanic draw attention the moment you plant more than a handful. The game flags “unauthorized farming detected,” a countdown starts, and a wave of bots marches in to tear up your plots. The strongest answer is a wall that survives the hits combined with a mechanism that kills anything touching it, and you can wire the whole thing to run on its own.

Quick answer: Build your fields inside a wall at least seven blocks high, then hang a second wall on Sports Suspensions and mount Piston-driven concrete slabs above it. Wire Sensors and a Timer through three Logic Gates (two NOR, one OR) so any bot that touches the hanging wall gets crushed automatically.

What triggers raids and how bad they get

Raids scale with what you grow and how long you farm. Higher-quality produce pulls stronger bots, and each night the waves get tougher. Keeping the raid level low limits which enemies show up, which directly changes how much wall you actually need.

Raid level	Bots that appear
Level 6	Totebots and Haybots only
Level 7–8	Adds Tapebots
Level 9–10	Adds Farmbots (hardest to defend against)

If you don’t need battery drops from Tapebots, aim for level 6 raids. Your farm stays smaller and cheaper, and you never have to deal with Farmbots. Taking breaks from planting resets the raid level back to something manageable.

Block durability that survives each bot

Damage to blocks is rolled by chance, and the roll depends on the bot doing the hitting. Tier 3 metal is close to indestructible against everything except the toughest enemies. Match your wall material to the raid level you plan to trigger.

Attacker	Block durability that holds
Totebots and Tapebots	Durability 5 is impervious
Haybots	Durability 8 tanks them (durability 6+ is nearly safe)
Farmbot projectiles	Durability 2 is safe
Farmbot melee	Nothing craftable is fully safe

For a level 6 setup, durability 8 walls shrug off both bot types. Concrete alone lasts only a few hits, so it is not enough as a standalone barrier.

Parts you need for the crusher wall

The automated crusher is built from a small set of parts. Gather these before you start so the wiring goes in one pass.

Logic Gate (three needed)
Timer
Sensor Level 1 (one per suspension)
Piston Level 2
Sports Suspension
Wood Blocks and Concrete Blocks (plus a high-durability block for the outer wall)

Automated farm defense wall in Scrap Mechanic — The completed farm defense wall in Scrap Mechanic. (Image: Axolot Games)

Build the automated crusher defense

Lay the farm foundation with wood blocks. Keep it moderate in size. A very large field makes the defense harder to build and pushes the raid level up faster.

Build a solid wall at least seven blocks high around all four sides so nothing can walk straight in. This is your main perimeter.

Place Sports Suspensions along all four walls. On a rectangular farm, add more suspensions to the longer sides. Interact with each Sports Suspension and set the stiffness to level 1.

Sports Suspension stiffness set to level 1 in Scrap Mechanic — Setting each Sports Suspension stiffness to level 1. (Image: Axolot Games)

Build a second wall from a high-durability block resting on those suspensions. Do not merge the corners, so each panel hangs freely on its suspensions and can move when struck.

Destroy one block right beside every suspension and drop a Sensor into that gap. Set each Sensor’s range to level 2, turn the sound on, and set the mode to Button.

Place three Logic Gates in a triangle and connect them. Set the two bottom gates to NOR and the top gate to OR.

Place a Switch near the mechanism and connect it to one of the bottom NOR gates. Put the Timer on the other side of the Switch, then connect the Timer to the OR gate and to that same NOR gate. Connect all the suspensions to the other NOR gate, and set the Timer’s delay to 1 second.

On top of the main wall, keep placing blocks outward horizontally until they reach the hanging suspension wall below. Mount your Pistons vertically and fix a concrete slab to them, three to five blocks wide. Build the same slab on all four sides, then connect every Piston to the OR gate.

Cover the top with any block you like to close the structure. The build is now complete.

How to confirm the defense works

When a bot pushes against the hanging wall, the suspension shifts, the Sensor triggers, and the logic chain fires the Pistons so the concrete slab slams down. A crush kills even the larger bots quickly. Test it on a single bot first. If the slab drops and destroys it without you touching a button, the wiring is correct.

Note: if the slab does not move, check that every suspension feeds the correct NOR gate, that the Pistons are all connected to the OR gate, and that the Timer delay is set to 1 second. A missing connection anywhere in the chain leaves part of the wall inactive.

Simpler alternatives if you skip the crusher

The crusher is the most reliable hands-off option, but several cheaper setups hold up well, especially at lower raid levels. Bots avoid water, saw blades, and drills, though they grow braver over time and the deterrents are not permanent.

Approach	How it protects the farm
Island farm	Haybots don’t swim and wander the shore; Totebots swim slowly and are easy to pick off in the water.
Hill or mountain base	Bots spawn at the bottom and often can’t climb, so little defense is needed.
Saw blades and drills	Mount them on the wall powered by controllers to save fuel; drills damage Haybots but not the small green Totebots.
Drill moat with pusher	Bots stop at a ramp edge above a drill-filled moat; a ceiling-mounted pusher swings out and shoves them in.
Mounted spud guns	Automated guns triggered by sensors fire on incoming bots at the wall.
Fence columns	One-block-wide, four-high Tier 3 metal columns with a one-block gap; bots try to walk through the gaps instead of attacking.

Powering saws, drills, and guns with controllers instead of engines means they cost no resources to run, so an automated perimeter can repel wave after wave while you collect bot drops in peace. Pair any of these with high-durability walls and you can hold a farm indefinitely, even before you commit to the full crusher build.