Our own circuit boards, in the lift station's control panel

Boards we design for the smart pump panel, with every chip soldered on them: the RV1126B processor and its memory, the station camera chip, the radar chip, the heat chip, LTE-M with a soldered eSIM, the station ADC and its isolated inputs, the e-paper and call light, the security chip, and on its own board the supply from the panel’s control circuit and a backup cell. They stand on the right side wall and inside the door of the same 24 × 20 × 8 in stainless panel, beside its own breakers and contactors; two latched leads join them. No plugs, ribbons or adapters inside.

Stage 1 of 6 done: shape and placementNot yet ready to manufactureUpdated 4 November 2026 · rev A-0

Design files Design review Quote pack Who can make it Our board platform

The board in 3D

Every part at its real size, in its real place. Turn it, zoom in, switch between the boards in the panel and laid flat, and click any part to see what it is. The chip bodies are simple blocks until each part's own 3D model is added.

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Drag to turn · scroll to zoom · right-drag to move · click a partDrag to turn · tap a part

Where everything is in the panel

Station camera and radarright side wall

A bare Sony IMX415 camera chip under a 102° M12 lens, 15° down through a 20 mm window, and a TI IWRL6432AOP 60 GHz radar chip behind the PC window beside it, each on a tab: the wet-well hatch, both riser gauges, the gate, and a person at the hatch in the dark.

Processor and radiosright side wall, top

The RV1126B with its memory on the main board, a heat block to the stainless wall; LTE-M with a soldered eSIM and BLE for the operator’s phone, both through one IP67 puck antenna in the top wall, because the closed stainless box stops the signal.

Station inputsright side wall, bottom

Spring-clamp terminals beside the pump leads for both current clamps, the 4–20 mA level loop (read through an isolated amplifier), the high float and both pump run calls (through optocouplers), and a relay contact to the panel’s own alarm light. PumpOne never switches a pump.

Heat cameradoor board

A Melexis MLX90640 heat chip on the inside of the door, looking straight back at both breakers, both contactors and overloads and the terminal strip.

E-paper, light and tonedoor board

The 2.13 in e-paper in its door window (level, pumps, power, last call), 8 call-light LEDs behind the slot and a piezo behind the tone holes; a 3D Hall chip under a magnet logs every door opening.

Power and backup cellpower board

The panel’s 120 V control circuit into a class II 5 V supply, and one soldered 18650 cell with a thermistor that keeps the power-lost call and level reports going for about 19 h.

The panel boards laid flat, both sides, every part at its real size

Laid flat: the door board on the left; the main board with its two sensor tabs on the right and the power board below it. Tap the drawing to open it full size.

Design review: checked before we order

Every board-level number PumpOne's calls depend on, checked against its target with the source of each number, using the rules every one of our boards shares (products/_shared/board-rules.mjs). Fixed means a lesson changed this board; to prove means it passes on paper and is measured on rev A before boards are ordered.

No check fails18 pass · 5 fixed by the review · 10 to prove before we order · 0 failDesign review of 4 November 2026

Area	Check	Our board	Target	Status
Camera	Station camera: a 100 mm discharge gauge dial on the riser at 1.99 m M12 lens, 102° across: about 37.6 px per degree across 3840 px. The needle reader needs about 40 px across the dial (est.); it reads only in daylight, glare or rain on the dial means no reading.	108.4 px	≥ 40 px	passes
Camera	Station camera: frame rate the calls need A standard mode of the IMX415.	5 fps at 3840 × 2160	chip: 30 fps at 3840 × 2160	passes
Camera	Station camera: data rate vs its 4-lane link 88 % spare on the link.	0.41 Gbps (10-bit)	≤ 80 % of 3.564 Gbps	passes
Camera	Station camera: a person (0.5 m wide) at the station gate at 3.35 m M12 lens, 102° across: about 37.6 px per degree across 3840 px. The person detector works from about 20 px across a person (est.); no faces are kept.	321.3 px	≥ 20 px	passes
Camera	Station camera: frame rate the calls need A standard mode of the IMX415.	5 fps at 3840 × 2160	chip: 30 fps at 3840 × 2160	passes
Camera	Station camera: data rate vs its 4-lane link 88 % spare on the link.	0.41 Gbps (10-bit)	≤ 80 % of 3.564 Gbps	passes
Camera	Panel heat camera: one contactor terminal block (25 mm) on the back plate at 0.29 m 32 × 24 pixels across 75°: 0.4 px per degree. The call compares a part with the matching part of the other pump while it runs, averaged over many frames; the chip is turned so its 75° runs across the back plate and its 110° from the breakers down to the terminal strip.	2.1 px	≥ 1 px	passes
Camera	Image processor load, all cameras 2 cameras into one image processor.	83 Mpx/s	≤ 360 Mpx/s (RV1126B ISP)	passes
Camera	AI engine time per frame One person model (int8) on the camera, woken by the radar; the needle reader runs on a still at each pump start. Level, currents and heat are read by the CPU. Measured on the dev kit.	3 TOPS	the gauge reader on each pump run and the person check within 5 s of the radar seeing someone	to prove on the dev kit
Power	Supply About 3.2 W watching (RV1126B 1.5 W, camera 0.3 W, radar 0.1 W, heat chip 0.1 W, ADC and inputs 0.1 W, LTE-M idle 0.2 W, Wi-Fi/BT 0.2 W, e-paper and light 0.2 W) and 7.5 W at a call with the cell charging at 1 A (est.): 38 % of the supply.	Mean Well IRM-20-5 PCB-mount 5 V 20 W supply (class II, listed) on the panel's own 120 V control circuit, on the power board	≤ 70 % of the supply (14 W)	passes
Power	Power cut Pulling the control circuit is part of the rev A tests at a station; a thermistor holds charging outside 0 to 45 °C (lesson: charge).	one soldered 18650 cell (Samsung INR18650-35E) on the power board: when the station loses power the RV1126B sleeps, the BG95-M3 sends the power-lost call at once and a level and pump report every 5 min, about 0.35 W, about 19 h on an aged, cold cell (est.)	the power-lost call and level reports for 12 h	to prove on the dev kit
Heat	RV1126B temperature, a summer lift station (40 °C air) with the panel under its sun shield The shaded stainless side wall on a hot day; counted at 55 °C. 1.5 W through a 20 × 20 aluminium block and gap pads to the 1.9 mm stainless right side wall (8 K/W, est.).	67 °C	≤ 85 °C (rated)	passes
Heat	Camera and radar chips away from the processor A warm sensor adds noise.	station camera 133 mm, radar 123 mm	≥ 30 mm	passes
Shock	Shock and vibration Door slams and vandal kicks on the door and the windows; about 50 g at the boards on their stand-offs (est.). MEMS clocks are fitted anyway, and the card socket is latched.	50 g (est.)	standard parts	passes
Software	Starts our software from the microSD card, no setup Owner requirement: power it from its own supply and our software runs from the card. Rev A and sale boards boot from the card; the eMMC holds no system copy (it ships empty, so the card always starts first: Rockchip tries the eMMC before the card) and keeps the station log and the call log. Updates write to the card with two system copies, only when both pumps are idle and the level is low, never during a high-level call.	microSD socket with a hinged, latched lid (Amphenol 101-00660 class), fitted on every board: our software starts from the card	card socket fitted on every board, latched	passes
Software	Card power switch and protection A card that hangs must be restarted by cutting its power, not the whole board; the card slot is the one place a person touches the electronics (lesson: sdstart). Change: U90, U91 added (4 Nov 2026, CricketOne card-start review).	1 power switch and 1 ESD array for 1 card socket	every socket: switched card supply, ESD on all 6 lines	fixed by the review
Software	The card wins the start Rockchip's start order is SPI flash, eMMC, card, USB: a written eMMC starts before the card. Proved on the dev kit: power on with a card in and the eMMC empty (lesson: sdstart). Change: eMMC ships empty and the loader reads the card first (4 Nov 2026; it used to say the eMMC kept a copy, which would have started instead of the card).	eMMC shipped empty; our loader reads the card first	the processor starts from the card every time	fixed by the review
Software	Card grade Consumer cards wear out and fail hot; the image is read-only with a separate data partition. Proved: 1,000 power cuts during writes on rev A (lesson: sdstart).	industrial pSLC microSD (Kingston Industrial or Swissbit S-56u), −40 to 85 °C	rated for the heat, cold and writes	to prove on the dev kit
Software	Clip buffer for an unsure call The rest of the memory holds Linux, the program and the AI model (lesson: clip).	19.8 s of 8-bit 5 fps video in 40 % of the 2 GB memory	≥ 3 s	passes
Radio	Wi-Fi/BT module clock The AP6256 runs from its own 37.4 MHz reference clock; a wrong or missing clock means no Wi-Fi or Bluetooth at all (lesson: wificlock). Change: the AP6256 had no clock on the board; Y3, a 37.4 MHz MEMS oscillator, added next to it (4 Nov 2026, from the CricketOne test-board circuit).	37.4 MHz MEMS oscillator (Y3)	37.4 MHz next to the AP6256	fixed by the review
Radio	LTE-M from inside the stainless panel A closed 304 stainless box blocks LTE-M, so the antenna sits outside it; the steel sun shield 40 mm above the puck is measured on rev A. Antenna outside the metal: the 2-in-1 IP67 puck antenna through the top wall, under the station's sun shield (lesson: enclosure). Measured on rev A (lesson: antenna). Change: CAD rev T: the bench LTE-M board and its antenna sat inside the closed stainless panel; a 2-in-1 IP67 puck now goes through the top wall under the sun shield, its two coax leads soldered to the main board (4 Nov 2026).	BG95-M3 with a soldered eSIM; its antenna is the LTE element of the puck through the top wall	certified module; callouts reach the on-call operator from a rural station	to prove on the dev kit
Radio	BLE for the operator's phone at the station Only pairing and the "operator here" mark that clears an entry call; everything else goes over LTE-M. Antenna outside the metal: the same puck antenna through the top wall (lesson: enclosure). Change: CAD rev T: the bench LTE-M board and its antenna sat inside the closed stainless panel; a 2-in-1 IP67 puck now goes through the top wall under the sun shield, its two coax leads soldered to the main board (4 Nov 2026).	AP6256 on the main board, its antenna the 2.4 GHz element of the same puck	pairing from the hatch, 4 m away (est.)	fixed by the review
Layout	Fast lines on a solid ground plane The layout rules go to the maker in the quote; the routed board's design rule check (0 copper errors, every keep-out kept) and the maker's impedance coupon prove them (lesson: planes).	RV1126B memory; 1 camera MIPI link (100 Ω pairs); USB (90 Ω); antenna feed (50 Ω, keep-out on every layer); card lines (length-matched, no vias under the socket)	ground on inner layer 1, supply on inner layer 2, no vias in pads, impedance lines routed first	to prove on the dev kit
Moisture	Conformal coating Hose-down, condensation in a cold panel and hydrogen sulphide from the wet well corrode bare copper; all three boards and both tabs get the same coat. Asked for in the quote (lesson: moisture).	coated	coated, sensors, sockets and antennas masked	passes
Fit	Board inside the product CAD, every part checked in 3D The board is checked on its own; the rev T CAD run places it in the product and checks every part in 3D (lesson: fit3d).	not yet in the product CAD	nothing touches	to prove on the dev kit
Camera	Every station call in view Every inView target from the CAD (the hatch centre and both corners, both riser gauges, the gate; a person at the hatch and at the riser; both breakers, both contactors and the terminal strip) from each lens or chip's real place on our boards.	Station camera: worst 33.9° / 10.4°; Hatch radar: worst 12° / 3.3°; heat camera: worst 16.5° / 44.6°	inside each sensor's view	passes
Camera	Station camera window The round 14 mm window was sized for the bench camera module; our M12 lens rim and the gate call, 34° to the side, need a 20 mm square (lesson: window). The radar window was already big enough. Change: CAD rev T: camera window Ø14 → 20 × 20 (4 Nov 2026).	20 × 20 (margin 2.3 mm); radar window 50 × 20 (margin 6.4 mm); steepest line of sight 38°	each view inside its window	fixed by the review
Fit	Sensor tabs on their brackets Each tab hangs off the main board and is held on its sensor's axis by a printed bracket; the brackets go in the rev T CAD and are checked in 3D there (lesson: fit3d).	Station camera: 0.3 mm inside the wall, hinge 13.6 mm; Hatch radar: 0.3 mm inside the wall, hinge 19.6 mm	chip or holder ≥ 0.3 mm inside the wall, hinge within the 40 mm flex	to prove on the dev kit
Fit	Door parts in their openings The door board sits 4 mm inside the door skin, so the e-paper face, the LEDs and the piezo are just behind their openings.	e-paper active area inside its 26 × 52 window, 8 call-light LEDs inside the 46 × 6 slot, the piezo over the tone holes	each inside its opening	passes
Safety	Control circuit kept on the power board The panel builder wires our power board like any listed component inside a UL 508A panel; creepage between the 120 V terminals and the low-voltage inputs is checked in the layout.	the panel's 120 V control circuit into a spring-clamp terminal, fuse, varistor, IRM-20-5 (class II); the pump run-call inputs through optocouplers; only 5 V, cell sense and SPI on lead L1	class II creepage on the power board; no 120 V on any other board	to prove on the dev kit
Safety	The station's own controls stay in charge The level controller and alternator keep running the pumps; PumpOne only reads and calls. The 100 Ω shunt is a passive part in the loop with nothing active in series, so the loop keeps working with the board unpowered; taking the board out needs a jumper across the loop terminals, written on the panel label.	level loop read through an isolated amplifier across a shunt, run calls through optocouplers, current clamps with no contact; one relay contact to the panel's alarm light	PumpOne never switches a pump; a board fault leaves the level controller working	passes
Security	Door tamper sensor The bench used a plunger switch at the door rim; the 3D Hall chip reads the magnet's field to a fraction of a millitesla, and the switch point is set on rev A.	TMAG5273 3D Hall chip on the door board, 21.4 mm from a Ø10 × 5 magnet on a printed boss on the body top wall	door opened = logged and signed	to prove on the dev kit
Fit	Leads and the antenna coax L2 crosses the door hinge in a strain-relieved loop with high-flex wire; the ADC's SPI on L1 runs at 1 MHz with series resistors.	L1 about 0.12 m (0.008 V drop), L2 about 0.59 m in the hinge loop (0.015 V drop); coax about 0.15 m	leads ≤ 0.15 V drop; L2 rated for 10,000 door openings; coax ≤ 0.25 m	to prove on the dev kit

Before we order the first boards, we prove these on the RV1126B development kit or in the rev A tests:

AI engine time per frame
Power cut
Card grade
LTE-M from inside the stainless panel
Fast lines on a solid ground plane
Board inside the product CAD, every part checked in 3D
Sensor tabs on their brackets
Control circuit kept on the power board
Door tamper sensor
Leads and the antenna coax

Where the design stands

1Shape and placementdone
Main board with two sensor tabs, power board and door board in the panel’s shape, all 62 parts placed at their real size, every view checked through its window in 3D and KiCad design rule check (0 violations).
2Schematicnext
Every wire between the chips, from the V1 core, C1 camera, station input and power circuits.
3Footprintsnext
The exact solder pads under each chip.
4Routinglater
Copper tracks on all layers, the camera lanes over the tab hinge.
5Files for the makerlater
Gerbers with copper, drill, mask, paste and the assembly parts list. These go to the board maker.
6Rev A boardsMar 2027
Made, assembled and tested on our fixture.

Design files (rev A-0)

These are the stage 1 files: the board's shape and where every part goes. A board maker needs the stage 5 files to build it.

All files (zip)Everything below in one download, with the quote and review KiCad boardpumpone-board.kicad_pcb: open with KiCad 10 (free)3D model (STEP)The bare boards for mechanical CAD Side A drawing (PDF)To the side wall and the door skin Side B drawing (PDF)Into the panel Parts and placement (CSV)Every part, its size, side and position

Who can make it

The panel set is an 8-layer main board with two tabs on flex hinges, a 4-layer power board and a large 2-layer door board. It needs a maker who builds rigid-flex tabs and fine-pitch ball-grid chips. We plan three quotes once the stage 5 files are ready: two from China for price, and one from the US for speed.

Maker	Where	Rigid-flex	HDI / layers	Assembly	Fit for us
PCBWayfirst quote	Shenzhen, China	yes, 6 to 16 layers	HDI up to 32 layers, 0.35 mm BGA pitch	yes, turnkey, incl. BGA and X-ray	Best fit for rev A: the rigid-flex board and its assembly in one order
NextPCBsecond quote	Shenzhen, China	yes	HDI, 6 to 32 layers	yes (PCBA)	Second quote, to compare price and lead time
ALLPCB	China (a network of partner factories)	yes, through partner factories	1 to 30 layers	yes	Third quote; check which factory builds it
JLCPCB	Shenzhen, China	no (flex only: 1, 2 and 4 layers, up to 490 mm)	HDI added Sep 2026	yes, incl. BGA	Not for the one-piece board today. Good for the test fixture, simple boards, and the fallback of separate rigid boards joined by soldered flex
Sierra Circuits (ProtoExpress)US quote	Sunnyvale, California, USA	yes	yes	yes, in-house, incl. BGA; turnkey in about 5 days	US option: fastest turn and engineering help, at a higher price
Cirexx	Santa Clara, California, USA	yes	yes	yes (turnkey or consigned)	Second US option
Advanced Circuits	Aurora, Colorado, USA	yes	check	yes	US quick-turn; check its rigid-flex assembly
Epec	New Bedford, Massachusetts, USA	yes	check	yes; also builds battery packs	US option that can also make a certified LiFePO4 pack

From each maker's own capability pages, checked 3 November 2026. Limits change, so each quote confirms them for our exact stack-up.

Full design notes

All 62 parts, what is on each piece, every connection, heat, power, the factory test, cost and timeline.

PumpOne: circuit boards of our own

What changed (4 Nov 2026). The rev A bench panel is built from bought boards joined by leads: a Raspberry Pi Zero 2 W, a Camera Module 3 Wide on a ribbon, an HLK-LD2450 radar module, an ADS1115 board, a Walter LTE-M board, an ATECC608 board, an MLX90640 board, a Waveshare e-paper HAT, a NeoPixel stick, a PowerBoost with a LiPo and an IRM-05-5 on flying leads. PumpOne now gets boards of our own, like every IEMI product, with the chips soldered straight on them:

The chips: the V1 core (Rockchip RV1126B, 2 GB LPDDR4X, 16 GB eMMC, AMPAK AP6256 Wi-Fi/BT module), a bare Sony IMX415 8 MP camera chip under an M12 lens holder (the C1 camera on the board), a TI IWRL6432AOP 60 GHz radar chip with its antennas on the package, a Melexis MLX90640 heat chip, a Quectel BG95-M3 LTE-M module with a soldered eSIM, a TI ADS131M04 ADC with a TI AMC1311 isolated amplifier for the station’s level loop, optocouplers for the float and both pump run calls, a 2.13 in e-paper panel, 8 call-light LEDs, a piezo, a TMAG5273 Hall chip for the door, the security and ID chips.
The shape: the panel is the same 24 × 20 × 8 in NEMA 4X stainless box, and the plain panel’s breakers, contactors and terminal strip stay on the back plate. So our boards stand on the right side wall, towards the wet well: an 8-layer main board (170 × 225 mm) with the processor and the camera and radar tabs at their windows, and below it a 4-layer power board (170 × 275 mm) with the panel’s 120 V control circuit, the backup cell and every station input on spring-clamp terminals, right beside the pump leads. A 2-layer door board (290 × 318 mm) sits 4 mm inside the door skin with the heat chip looking straight back at the breakers.
A fix in the same run: the bench LTE-M board and its antenna sat inside the closed stainless box, which stops the signal (new shared lesson: enclosure). A 2-in-1 IP67 puck antenna (LTE-M and 2.4 GHz) now goes through the top wall under the station’s sun shield, its two coax leads soldered to the main board. The camera window grows from a 14 mm disc to a 20 mm square for our M12 lens and the gate call, 34° to the side. Both drawn in the CAD the same day (rev T).
Made from the shared rules: MEMS clocks, the latched microSD card with our software on every board, conformal coating against hose-down, condensation and hydrogen sulphide from the wet well, a thermistor on the backup cell, the camera and radar 30 mm or more from the processor, every line of sight under 82° from its wall.

The bench panel stays the test rig until the boards arrive. PumpOne only reads and calls: the station’s level controller and alternator keep running the pumps.

1. The shape: three boards, two tabs

Piece	Size	Layers	Where	What
Main board	170 × 225 mm, 1.6 mm	8	standing 20 mm inside the right side wall, top	the V1 core, card, security, LTE-M with eSIM, Wi-Fi/BT, antenna coax pads, lead headers
Sensor tabs (2)	16 × 16 mm, 0.8 mm, on 40 mm flex hinges	4	each on its sensor’s axis, the lens or chip just inside its window	IMX415 (station camera, 15° down), IWRL6432AOP (radar, 10° down)
Power board	170 × 275 mm, 1.6 mm	4	8 mm off the right side wall, below the main board	120 V control-circuit terminal, fuse, IRM-20-5, backup cell and charger, ADC, isolated amplifier, optocouplers, alarm relay, station terminals
Door board	290 × 318 mm, 1.6 mm	2	4 mm inside the door skin	e-paper, call light, piezo (side A); heat chip, tamper Hall chip (side B)
Antenna	2-in-1 IP67 puck, about Ø60 × 22 (est.)		through a Ø17 hole in the top wall, under the sun shield	LTE-M and 2.4 GHz, two RG-178 leads soldered to the main board

Lead L1 (power board to main board: 5 V on two pairs, cell sense, the ADC’s SPI) is about 0.12 m of 20 AWG with Molex Micro-Fit 3.0 10-pin latched ends. Lead L2 (main board to door board) is about 0.6 m of high-flex 24 AWG in a strain-relieved hinge loop, 14-pin latched ends.

2. What is on the boards

Main board, side A (to the wall): RV1126B (U1) with a 20 × 20 heat block (HS1) to the stainless side wall; LPDDR4X (U2), eMMC (U11); the station camera tab (U200, IMX415 under a 102° M12 lens, 15° down through the 20 × 20 window) and the radar tab (U250, IWRL6432AOP, 10° down behind the 50 × 20 PC window), each held on its axis by a printed bracket.

Main board, side B (into the panel): decoupling field (C1), power (U3), 24 MHz and 32 kHz MEMS oscillators (Y1, Y2), ATECC608B (U8), ID chip (U9), the latched microSD (J1, reached by opening the door), AP6256 (U5), BG95-M3 (U6) with its eSIM (U6S), the antenna coax pads (PD2), camera and radar supplies (U21, U24), ESD array (U25), eFuse (U42), lead headers (J2, J5), factory pads (TP1).

Power board, side B (into the panel): spring-clamp terminal for the panel’s 120 V control circuit (J10), fuse and varistor (F10), IRM-20-5 (PS1), the 18650 holder and cell (BT1) with its thermistor (RT1), the charger (U50), lead header (J12); at the bottom, beside the pump leads and the terminal strip: the ADS131M04 ADC (U51), the AMC1311 isolated amplifier across a 100 Ω shunt in the level loop (U53), three optocouplers for the pump 1 and pump 2 run calls and the high float (U54–U56), current-clamp burdens and filters (U57), input surge guard (U58), the alarm relay (K1), and spring-clamp terminals for the current clamps (J13), the level loop and float (J14), the run calls (J15) and the alarm contact (J16).

Door board, side A (to the door): the e-paper panel (EPD1) in its 26 × 52 window, 8 call-light LEDs (D1–D8) behind the 46 × 6 slot, the piezo (BZ1) behind the tone holes. Side B: the MLX90640 heat chip (U240) looking straight back at both breakers, both contactors and overloads and the terminal strip, its supply (U23), the TMAG5273 Hall chip (U7) at the top edge under the magnet boss, the e-paper booster and FPC pads (U61), LED level shifter (U62), piezo driver (U63), lead header (J20) and ESD array (U64).

3. Every connection, checked

Link	How	Checked against
Camera chip to RV1126B	4-lane MIPI CSI-2 over the tab hinge	IMX415 data sheet: 891 Mbps per lane; at 5 fps it uses 0.41 Gbps of 3.56
Radar chip	SPI and a frame interrupt over the tab hinge	TI IWRL6432AOP data sheet
Heat chip, Hall chip	I²C at 3.3 V over lead L2 at 100 kHz	Melexis MLX90640, TI TMAG5273 data sheets
E-paper	SPI, busy and reset over L2; the panel’s FPC hot-bar soldered	Good Display GDEY0213B74 data sheet
Station inputs	ADS131M04 on SPI over L1 at 1 MHz; the level loop through the AMC1311; run calls and float through optocouplers	TI ADS131M04 and AMC1311 data sheets
LTE-M	USB 2.0 and UART on the main board; eSIM soldered; coax to the puck	Quectel BG95 hardware design
Wi-Fi/BT	SDIO and UART on the main board; coax to the puck	AMPAK AP6256 (RV1126B SDK default)
Power in	the panel’s 120 V control circuit, fused, into the class II IRM-20-5; 5 V on L1 into an eFuse at 3.5 A; L1 drops 0.008 V at 2 A	Mean Well IRM-20 data sheet
Alarm	dry relay contact on a spring-clamp terminal to the panel’s own alarm light or autodialer	Omron G5V-1 data sheet
Card	SD bus to the RV1126B, latched socket	Amphenol 101-00660 family drawing

Every mating pair is checked against the makers’ documents, never “same as” another board.

4. Heat

About 1.5 W from the RV1126B goes through the heat block into the shaded stainless side wall (8 K/W est.), so the chip sits near 67 °C with the wall at 55 °C on a hot day. The camera and radar chips are 123 mm or more from the processor.

5. Power budget (est.)

State	Draw
Watching: radar 10 Hz, heat chip 1 Hz while a pump runs, a camera frame every 10 s, ADC at 4 kHz, LTE-M idle	3.2 W
A call: the person model, light and tone, LTE-M callout, the cell charging at 1 A	up to 7.5 W, 38 % of the 20 W supply
Power lost: RV1126B asleep, BG95-M3 sends the call and a level report every 5 min	0.35 W, about 19 h on an aged, cold cell

6. Factory test (every board, every time)

Spring-pin fixture on TP1 and the door and power boards’ pads: 5 V in, the eFuse trip at 3.5 A, every rail, boot from the card, a frame of a test chart from the camera, a corner reflector seen by the radar, a hot plate seen by the heat chip, a test current through each clamp input, a 4 to 20 mA source on the level input, 120 V on each run-call input, the float input, the relay, the e-paper and all 8 LEDs, the piezo, the Hall chip with a magnet, the security chip’s key, the LTE-M and BLE links on a test puck.

7. Who makes what

One maker makes the main board with its two tabs, the power board and the door board, assembles them (turnkey) and makes leads L1 and L2 to length. We supply the microSD cards with our software and the lens focused at 3 m (est.). The panel builder fits our boards, the windows and the puck antenna into the listed panel. The quote pack is /build/pumpone-quote.

8. Cost per panel, electronics (est.)

Item	Cost
V1 core (RV1126B, 2 GB LPDDR4X, 16 GB eMMC, power, AP6256)	$32
IMX415 camera chip, holder and lens	$14
IWRL6432AOP radar chip	$12
MLX90640 heat chip	$45
BG95-M3 LTE-M and eSIM	$15
2-in-1 IP67 puck antenna	$25
ADC, isolated amplifier, optocouplers, relay, station terminals	$18
IRM-20-5, mains terminal, fuse, cell, charger	$14
E-paper, LEDs, piezo, Hall, security, ID, socket, passives	$10
Boards (8-layer main with two tabs, 4-layer power, 2-layer door), 1,000 panels	$35
Leads L1 and L2	$4
Assembly and test	$15
microSD card with our software	$4
Total	about $243 per panel (est.)

The bench panel’s bought boards cost about $316 at qty 1 (Pi Zero 2 W, camera, radar module, ADC, Walter, MLX90640 board, e-paper, supply, backup and small boards; the current clamps stay), so our boards are about $73 cheaper per panel at 1,000 (est.).

9. Timeline

Step	When
Shape and placement (this page)	done, 4 Nov 2026
Rev T CAD: the boards in the panel CAD, every part checked in 3D; the camera window and antenna hole already drawn	next
Schematic, footprints, routing	Dec 2026 – Jan 2027
Rev A boards made and tested	Mar 2027 (est.)

10. Still to check

LTE-M from the puck under the steel sun shield at a rural station, against the bench Walter with its antenna inside the box.
The rev T CAD changes still to draw: the heat block, the tab brackets, the board stand-offs, the magnet boss and the printed shield over the 120 V terminals.
The level loop’s shunt with the station’s own level controllers (some loops have little spare voltage for 2 V more).
The 600 mm door lead’s hinge loop over 10,000 door openings.
Hydrogen sulphide: coating and the stainless windows’ seals after a year at a sewage station.

Sources

Rockchip RV1126B (Forlinx FET1126Bx-S): https://www.forlinx.net/product/rockchip-rv1126b-som-fet1126b-bj-s-174.html
Sony IMX415 (8.46 MP, 4-lane MIPI): https://www.sony-semicon.com/en/products/is/security/security.html
TI IWRL6432AOP: https://www.ti.com/product/IWRL6432AOP
Melexis MLX90640: https://www.melexis.com/en/product/MLX90640/Far-Infrared-Thermal-Sensor-Array
Quectel BG95-M3: https://www.quectel.com/product/lpwa-bg95-m3/
TI ADS131M04: https://www.ti.com/product/ADS131M04
TI AMC1311: https://www.ti.com/product/AMC1311
TI TMAG5273: https://www.ti.com/product/TMAG5273
Good Display GDEY0213B74: https://www.good-display.com/product/391.html
Mean Well IRM-20: https://www.meanwell.com/Upload/PDF/IRM-20/IRM-20-SPEC.PDF
Omron G5V-1: https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5v_1.pdf
Microchip ATECC608B: https://www.microchip.com/en-us/product/atecc608b
Samsung INR18650-35E: https://www.samsungsdi.com/
The panel: products/pumpone/cad/pumpone-cad.mjs (rev A, camera window and antenna hole rev T); the boards: products/pumpone/hardware/pcb/pumpone-board.mjs

Design review (4 Nov 2026)

Every board is checked by the same rules (products/_shared/board-rules.mjs), one for each lesson any of our boards has taught us. PumpOne’s boards were made with every rule from the start: 18 pass, 5 fixed, 10 to prove, 0 fail. The full review, with every number and its source, is on the board page. It shows:

Camera pixels: a 100 mm discharge gauge on the riser (2 m) fills about 108 px against a 40 px need; a person at the gate (3.4 m) about 320 px against 20; the 8 MP chip at 5 fps uses 12 % of its link. The heat chip puts about 2 px on a 25 mm contactor terminal block from the door.
Every station call in view: the hatch centre and both corners, both riser gauges and the gate; a person at the hatch and at the riser; both breakers, both contactors and the terminal strip, from where each lens or chip really sits.
The antenna is outside the stainless box (fixed, new lesson: enclosure): a 2-in-1 IP67 puck through the top wall carries both LTE-M and BLE. The rule is now checked on every board, and the boards with radios in metal (DockOne, KitchenOne, PoolOne, RacketOne, ChillOne) each name the window their antenna uses.
The camera window is a 20 mm square (fixed): sized for our lens rim and the gate call. Drawn in the CAD the same day.
The station’s own controls stay in charge: the level loop is read through an isolated amplifier across a passive shunt, the run calls through optocouplers, the pump currents with clamps that touch nothing.
The latched microSD (J1) is fitted, and our software starts from it; updates run only when both pumps are idle and the level is low.
Fast lines on a solid ground plane (to prove, lesson: planes, from the CricketOne test-board layout of 4 Nov 2026): RV1126B memory; 1 camera MIPI link (100 Ω pairs); USB (90 Ω); antenna feed (50 Ω, keep-out on every layer); card lines (length-matched, no vias under the socket). Ground on the layer next to the parts (inner layer 1, supply on inner layer 2; the whole bottom of a 2-layer section), one via beside each ground and supply pad and none in pads, no copper or vias in the antenna keep-out on any layer or under the card socket, the impedance lines routed first with a test coupon. The quote asks for it; the routed board’s design rule check proves it.
To prove on rev A: the AI time, the power-cut run on the cell, LTE-M under the sun shield, the tab brackets, the 120 V creepage, the tamper magnet, the leads and the boards in the rev T CAD.

The request for quote is /build/pumpone-quote.

New shared rule (4 Nov 2026, from the CricketOne test-board circuit): the Wi-Fi module’s own clock. Drawing CricketOne’s circuit pin by pin found that the AP6256 Wi-Fi/Bluetooth module runs from a 37.4 MHz reference clock, which our board notes had as 26 MHz or left out. Every board with an AP6256 is now checked for a 37.4 MHz clock beside it (MEMS where the product takes knocks). On this board the AP6256 had no clock of its own on the board; Y3, a 37.4 MHz MEMS oscillator, now sits next to it on side B. The review shows it under Radio (lesson: wificlock).