Roller carrier

Carrier board Roller-H2 Zero v2

2-layer board (41.5 × 29.1 mm, U-shaped) that plugs directly onto the 3-pin keypad header of the original controller board. A Waveshare ESP32-H2-Zero sits on spacers above the regulator and dividers and is soldered in by hand; JLCPCB can assemble everything else.

Top	Bottom

The H2-Zero in the renders is a simplified model generated by ../lib/make_footprints.py from the product photos. For J1 the renders use WAGO's 3D model of the 2060-452/998-404 (from WAGO's CAD download, not included here because of its terms of use); the board itself references a simplified model of the terminal from the same script.

Connectors

USB-C, BOOT and RESET are on the H2-Zero itself.

Circuit

USB-C, ESD protection, BOOT/RESET and the EN circuit are on the H2-Zero.

• Battery+ (VBAT_RAW) → PTC 100 mA (F1) → reverse polarity protection P-MOSFET AO3407A (Q1, gate via 100 kΩ to GND) → VBAT → 10 Ω (R1) → VIN. The two WAGO poles are connected by a copper area on both layers; the motor current only flows through this area, not through the electronics.
• VIN: TVS SMF13A (D1) against spikes from the motor, 10 µF (C1) → TPS629203 (U1) → 3.3 V to the 3V3 pin of the H2-Zero. VSET open = 3.3 V, MODE 64.9 kΩ = auto PFM/PWM 1 MHz, EN (pin 7) to VIN, PG open. The 5V pin of the H2-Zero stays open.
• Dividers 1 MΩ / 220 kΩ / 100 nF each (factor 5.55, 12.6 V → 2.27 V): battery (after the reverse polarity protection), motor+, motor−, solar.
• Keys: DOWN/UP each via 1 kΩ to the H2-Zero, connected 1:1 between J3 and J4.
• 32 kHz crystal Y1 (CL 12.5 pF) with C11/C12 (18 pF each) on IO13/IO14.
• Regulator and dividers sit below the H2-Zero. There is no copper on either layer below its ceramic antenna (bottom end, at the board edge).
• Ground only via J3 (keypad GND). Do not connect battery− (20 mΩ shunt on the original board).

GPIO assignment

Matches the firmware defaults:

Mounting the H2-Zero and height

The H2-Zero is soldered directly into J6/J7 with its pin headers. The plastic strip of the header (about 2.5 mm) acts as spacer: the regulator and dividers sit below it, the tallest part is the inductor L1 at 1.2 mm.

• Height above the board: 2.5 mm spacer + 1 mm H2-Zero board + about 3.2 mm USB-C connector ≈ 6.7 mm.
• In the housing of the Heim & Haus controller there are only about 6 mm free above the board at the left edge. Check before soldering that the lid closes; if needed, shorten the plastic strip (leave at least 1.5 mm above L1).
• Cut the pins flush on the bottom side: J3 plugs onto the keypad header there.

Preparing the H2-Zero

1. Flash it before soldering via its USB-C. Later, flash over USB only without battery (J1 open), otherwise its LDO and the TPS629203 feed the 3V3 rail at the same time. Further updates via Zigbee OTA.
2. Remove the RGB LED (IO8): it draws 0.5–1 mA even when off.
3. The H2-Zero's LDO (ME6217) is back-fed via 3V3 and draws around 50 µA according to its datasheet. Measure the sleep current; if it is clearly too high, remove the LDO before soldering (USB flashing then only works with the battery connected, OTA is unaffected).

Generating and checking

python3 make_board.py                         # placement, nets, silkscreen
python3 route.py /path/to/freerouting.jar     # Freerouting, GND areas, DRC (up to 5 attempts)
python3 ../fab.py carrier                     # fab/gerber.zip, bom_jlc.csv, cpl_jlc.csv

route.py always starts from a fresh make_board.py. Freerouting (2.x, needs Java) does not give the same result on every run and occasionally hangs; the script checks every attempt with the DRC and routes again up to five times. A run takes 2–7 minutes.

Expected: 0 DRC errors, 0 unconnected items. The remaining "silk_edge_clearance" warnings are intended (header pins protrude over the edge).

Ordering at JLCPCB

1. Upload fab/gerber.zip, 2 layers, 1.6 mm.
2. PCB Assembly (Economic), Assembly side: Top, fab/bom_jlc.csv and fab/cpl_jlc.csv. All parts are regular JLCPCB stock, no Global Sourcing needed. JLCPCB solders the 90° headers J4 and J5 (C92159) by hand. J3 (8.5 mm socket, C42431866) is in the BOM/CPL but sits on the bottom side: with "Assembly side: Top", JLCPCB leaves it out (Economic assembles one side only).
3. In the placement preview, check the rotation of U1 (SOT-583, pin 1 = FB/VSET), Q1, J1 (wire entry up), J4 (pins towards the board centre) and J5 (pins up).

Assembly by hand

1. If J3 is not fitted: solder a 1×3 socket (8.5 mm) from the bottom side, opening away from the board. Plug it onto the keypad header of the original board to align it, then solder.
2. Measure before soldering the H2-Zero: battery on J1 → 3.3 V at J6 pin 3, ≈ 2.2 V at J6 pin 8 (IO4) with a 12.2 V battery.
3. Solder the H2-Zero (flashed, RGB LED removed) with its pin headers on spacers into J6/J7, USB-C towards the "USB" label. Cut the pins flush on the bottom side.
4. Cut the red battery wire, put both ends into J1, plug the board onto the keypad header and the keypad into J4.
5. Optional: connect J5 to the controller's terminal block, SOL to solar + (yellow), M+ and M− to the motor terminals (blue, brown). Without these wires the firmware works with the battery voltage alone (see the main README).