OOMWOO hardware bring-up: wheels, fans and brushes
OOMWOO is built from sourced vacuum parts – Roborock drive wheels, off-the-shelf blower fans, iRobot cliff sensors. Before the I/O board can be laid out, each part has to be brought up on the bench: identify the connector, work out the pinout, and measure what it actually draws. This post collects those results as they land.
Drive wheels
The drive wheel is a Roborock S5 Max assembly – motor, gearbox, Hall encoder and a wheel-drop switch in one unit. Driving the motor at 15V or less and watching the encoder output confirms the pinout: pulse frequency is proportional to wheel speed.
Roborock S5 Max wheel assembly
connector JST ZH 1.5mm 7-pin male (board side female)
current 0.14A no load, 1.7A stall at 14.4V
pin 7 wheel-drop switch, on
pin 6 wheel-drop switch, common
pin 5 Hall Vcc 3.3-5V (orange)
pin 4 Hall OUT, open collector (blue)
pin 3 Hall GND (brown)
pin 2 MOT-
pin 1 MOT+Suction fans
The blower is the other big load. The BL24131607 runs straight off the 4S pack, takes a PWM input and reports back a tacho signal.
BL24131607 suction fan, DC 14.4V
connector JST PH 2.0mm 5-pin female
current 1.7A free, 2.7A with the intake blocked, at 15V
pin 5 + (VMOT)
pin 4 - (GND)
pin 3 SP (PWM)
pin 2 FG (tacho)
pin 1 ID (20K pulldown to GND, likely fan-presence detect)Four more fans – 20N704R990F, MSD-C-3, MSD-D and 20N709U020 – share a single 4-pin pinout, which makes them drop-in alternatives:
20N704R990F / MSD-C-3 / MSD-D / 20N709U020, DC 14.4-15V
connector JST PH 2.0mm 4-pin female
pin 4 VMOT
pin 3 GND
pin 2 PWM, low = off
pin 1 TACH, open collectorOthers use different housings: 22N704V160 and BL24131616 on JST PA 2mm 5-pin, BL27302101 on JST PA 2mm 6-pin, MSD-G-V1 on Molex Micro-Fit 3.0. Pinouts for these are in the spec.
Main brush
The main brush motor from a Roborock S50/S51/S55 or XIAOWA C10 measures 0.26A no load and 3.5A stall at 14.4V.
Cliff sensors
The iRobot cliff sensor loom lands on a JST PAD 2.0mm 8×2 housing, mating JST S16B-PHDSS or B16B-PADSS on the board.
Why measure
Salvaged vacuum parts mostly come without datasheets, so the spec started out with rough estimates. Measured numbers replace them, and they are what sizes the H-bridges and load switches, the wire gauge and the battery budget. An afternoon on the bench is a lot cheaper than a board respin.
Where this lives
Every pinout, connector part number and measurement goes into docs/SPEC.md in the oomwoo-pcb repo, which is what the schematic is drawn against. If you own one of these parts, a measured current or a confirmed pinout is a genuinely useful contribution – see the RFC board, particularly part-specs and io-pcb.
