FarmLoop Stage 2 assembly, Bambu H2S

Read through the entire guide before you start. Have every part from the kit laid out where you can reach it, and make sure the printer is powered off and unplugged before opening anything.

Approximate time: 45-60 minutes.

Board version matters

• V2.1 boards use a Y-cable to connect to the actuators.
• V3.1 boards use the orange connector.

Check which board version shipped with your kit before wiring. The two are not interchangeable.

H2S pusher head - additional video

For the H2S pusher head, also watch the dedicated walkthrough we released on YouTube. It covers the pusher-head specifics this article doesn’t.

Prerequisites

• Bambu Lab H2S with latest firmware installed
• FarmLoop Stage 2 kit - door actuator, bender actuators (2×), wire harness, limit switches, PCB, screws, adhesion strips, and cable ties
• Printed parts from Makerworld
• FarmLoop Pro App subscription, sign up at app.3d-farmers.com
• A clean, flat work surface large enough to lay every part out
• ~45-60 minutes uninterrupted

Before you start

• Power off and unplug the printer.
• During operation, never reach into the printer while a bender is active - the actuator exerts significant force.
• Before installing a bender, make sure the build plate is raised above the bender position. Remove it first if it’s below.
• Parts are designed to fit smoothly. If a component needs excessive force, stop and check orientation.
• Door sensors break easily - do not apply force near them when fitting the benders.
• Route all cables away from moving parts. Loose cables can foul the Z-axis lead screws, the toolhead, or the build plate.

1. Assemble the door opener

1. Press the button into the designated hole in the lid.
2. Fix the button using the rubber ring and metal ring.
3. Attach both wires to the button terminals.

4. Slide the actuator into the bottom part until it is fully seated.
5. Align the lid with the base and press them together until they click/lock into place.

2. Set up the benders (×2 - repeat for each)

1. Slide each actuator into its bender bracket until fully inserted.
2. Check that the actuator is facing the correct direction - the cable must sit in the designated gap.
3. Attach one hook to each actuator and tighten the screws firmly so the hook does not move.
4. Insert the bender holder into the printer frame.

5. Press the endstop switch into the slot in the left floor part.

Tip

Repeat steps 1-4 for the second bender. Step 5 (the endstop) is on the left floor part only.

3. Prepare the 3D printer

3.1 Remove the lid

Remove the printer’s lid and set it aside - you’ll re-fit it at the end.

3.2 Install the scraper on the print head

H2S-specific

The H2S uses screws to fix the scraper. The H2D and H2C use a different fitment - make sure you’re on the right article for your printer.

1. Remove the top two screws from the print head.
2. Attach the scraper to the same position.
3. Reinsert the same two screws to secure it.

3.3 Replace the original feet with tilted feet

Remove every original foot and replace each one with a tilted foot, screwing it in firmly.

3.4 Swap the door hinge

1. Remove the bottom two screws from the original door hinge.
2. Position the new door hinge in the same place.
3. Reinsert the same two screws to secure it.

3.5 Place the lid lifter

Place the lid lifter into its designated slot. Check the label on the lifter so you fit the correct one for the H2S.

3.6 Route the wire harness into the print room

Insert the wire harness into the print room through the designated opening.

3.7 Attach the benders to the print room

Attach one bender to each side of the print room. Check the direction of the hook before pressing it into place.

Door sensors are fragile

Do not apply force near the door sensors while fitting the benders - they break easily.

Keep the cable clear of the Z-axis lead screw: hold it back against the frame with an adhesion strip, then lock it down with a cable tie at the stress point so it can’t sag into the lead screw or other moving parts.

3.8 Thread the wire harness through the bottom parts

Thread the wire harness through all bottom parts in order, following the intended routing path.

3.9 Connect the actuators to the harness

Connect each actuator to its corresponding connector on the wire harness. The Y-cable (V2.1) or orange connector (V3.1) sits between actuator and harness - match it to your board version.

3.10 Screw down the bottom parts

Align the bottom parts with the screw holes on the printer floor and screw them down firmly.

3.11 Route the harness behind the side panel

1. Loosen the side panel by removing the single screw on its inside face.
2. Slide the wire harness guide into the gap between the chassis and the side panel.
3. Route the wire harness through the guide.
4. Reattach the side panel using the same screw.

3.12 Verify free movement of the print head

Adjust the wire harness so it lies flat and tight against the side of the printer. Then manually move the print head to all corners and confirm it moves freely without pulling or snagging the harness.

3.13 Secure the wire harness

Secure the wire harness to the printer frame using tape at regular intervals and zip ties at stress points (where the harness flexes or could snag).

Don’t skip this - it protects your printer

A loose or sagging harness can be caught by the Z-axis lead screws, the toolhead, or the build plate mid-print - tearing the cable or jamming the machine. Fix it down firmly with the adhesion strips and cable ties at every stress point before moving on.

3.14 Install the PCB holder

1. Remove the top screw from the back panel.
2. Position the PCB holder against the panel.
3. Reinsert the same screw through the holder to fix it in place.

3.15 Install the door opener

Slide the door opener into the slot at the bottom front of the printer until it sits flush.

3.16 Connect all cables

Connect every cable. Attach cable clips where needed and press each cable firmly into its clip so nothing dangles or works loose.

3.17 Attach the door opener to the door handle

Attach the door opener to the door handle.

3.18 Re-fit the lid + clip the bed

1. Place the lid onto the lid lifter.
2. Clip the bed using the clips on both sides.

✅ Done!

Next step

Continue the Start here flow at step 3 (firmware update) once your hardware is mounted.

For door-button controls, OTA mode, MQTT setup, and the LED-signal reference, see the sections below - the firmware behaviour is identical to the P / X series.

Operation

Door-button controls

The DOOR BUTTON is the manual-control button on the automatic door console. Its function depends on the current system state:

System state	Action	Result
Idle	Short tap	Door control (open/close toggle)
Idle	Long press (3+ seconds)	Enter test mode
Any state	5 quick taps within 3 seconds	Enter OTA configuration mode
Reset after safety-check failed	Single tap	Recovers from SAFETY_FAILED state. Homes bender, closes door, returns to initial state.

OTA mode (firmware updates + trigger-mode setup)

OTA is how you flash new firmware and how you wire up the Digital trigger mode (printer IP + LAN access code). The full walkthrough - entering OTA mode, accessing http://farmloop.local, uploading a .bin file - lives on the Accessing the board (OTA mode). Trigger-mode setup is on the Trigger mode page.

LED signals

After the board boots, the LED shows a sequence indicating connection status.

Successful startup sequence: 3 quick blinks → 5 slow blinks → 10 fast blinks. If you see all three patterns, the board is fully connected to the printer.

During OTA mode: the LED blinks rapidly at 4 Hz continuously until you exit or the timeout is reached.

LED pattern	Meaning	Action needed
3 quick blinks	Boot successful	None, normal
5 slow blinks	Wi-Fi connected	None, good
10 fast blinks	MQTT printer connected	None, fully operational
2 long blinks	Wi-Fi connection failed	Check SSID and password in OTA
4 long blinks	MQTT connection failed	Check printer IP and access code

Support

• Contact: Open a support ticket
• Skool community: skool.com/3dfarmers
• Community (Pro members): log in at app.3d-farmers.com to access the Discord invitation

If your kit arrived damaged, email us with photos and your order number before opening anything further.