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VisionDesign rev A, 27 Oct 2026: CAD, fit checks and assembled 3D model done; not built

CalvingPen

One camera and one trough head per calving pen: the labour clock, the calf out and the cow's water, on one bell

One kit per calving pen does the jobs of CalveClock and TroughTally: a PenEye camera times each labour (stage 2 clock, calf out, calf not moving) for the barn Edge Hub, and the same PenEye cable powers and reads a head on the pen's water trough (supply cut, float stuck, ice, heater off, stray voltage, and how much the fresh cow drank). One hub, one PoE cable per pen, one bell, one app.

Who buys it
Spring-calving beef and dairy farms with 40–300 cows and 2–8 calving pens that already check pens at night and already have a self-filling bowl or small trough in each pen.
Why it pays
Bought separately, a 4-pen barn costs $2,455 + $243 a year (CalveClock hub, 4 PenEyes and BarnBell; 4 TroughTally heads with WinterWatch and a LoRaWAN gateway). CalvingPen is $2,190 + $149 a year (target), with no gateway and no AA cells.
Target price
$2,190 for a 4-pen barn kit + $149/year; $399 per added pen (target)
First-minute wow
The bell rings at 03:10: 'Pen 3: calf out 50 min, cow has not been to the trough and the trough supply is cut.' The camera and the meter told one story.
See the CAD designConcept page
CalvingPen concept: the idea and where each part goes
The concept. The CAD design is below, under Printable CAD.

What the research found

And how this design answers it

  • Two products, three radios (PoE, LoRaWAN, Wi-Fi) → one Edge Hub brain, one PoE cable per pen and the farm Wi-Fi for the bell
  • TroughTally's RAK3172 LoRa radio, AA cells, whip and $179 gateway → a XIAO RP2040 in the trough head, powered and read over one 10 m RS-485 lead from the PenEye
  • A trough meter that saw only a herd total → in a one-cow calving pen it sees one cow, so 'fresh cow has not drunk' becomes an alert
  • Trough faults rung with the pen state: a supply cut or iced bowl in a pen where a cow has just calved rings the bell at once
  • New lead-clip keeps the trough lead on the gate rail, out of the cow's reach

Use case

Pen 3 at 02:00 in February

FarmerHerd workerVet

  1. 01Trigger: a heifer in pen 3 shows feet at 01:20; the pen's heated bowl lost its heater on a tripped socket at midnight
  2. 02Detect: the PenEye times stage 2; the trough head sees heater current gone and water at 1.5 °C
  3. 03Alert: the bell rings at 02:20 for stage 2 over 60 min; the same card says 'pen 3 heater off, water near freezing'
  4. 04Act: the farmer helps the heifer, resets the socket on the way out and sees her drink 9 gal at 02:58 on the phone

Outcome: One trip, a calf delivered on time and a fresh cow with open water, instead of an iced bowl found at breakfast

How it works

Architecture

  1. 01

    Sense: a PenEye camera with IR over each pen; a trough head with meter, ultrasonic level, water temperature, heater CT and stray-voltage probe

  2. 02

    Decide: the Edge Hub's Pi 5 + Hailo-8 runs the calving state machine and the trough rules, and joins them per pen

  3. 03

    Send: PoE Ethernet from each PenEye; RS-485 from trough head to PenEye; MQTT to the BarnBell; push to phones

  4. 04

    Tell: the BarnBell by the bed, phone alerts with clips, and a per-cow calving and water log

Hardware

Real parts, buyable today

Bill of materials: about $1,799 for a 4-pen kit (hub $327, $358 a pen, bell $39) at qty 1 (est.).

BlockPartWhy this part
BrainIEMI Edge Hub: Raspberry Pi 5 4GB + AI HAT+ 26 TOPSRuns every pen camera and every pen trough
Pen cameraPi Zero 2 W + Camera Module 3 Wide NoIR + 2 x 850 nm IRSees the water bag or feet from the opposite corner
Trough headXIAO RP2040 + A02YYUW + DS18B20 + MAX3485Level, temperature and meter pulses, no radio, no cells
Water meterDAE AS200U-75P pulse meterInflow: supply cut, float stuck, how much she drank
WinterSCT-013-030 CT + 316 electrode + ground rodHeater on or off, and volts on the water
BellXIAO ESP32-C3 + NeoPixel Ring 12 + piezoRings by the bed, not just a phone

Mechanical

Printable CAD

10 parts, generated from code and checked as closed solids. Pick a part to inspect it, or download the STL files to print.

Loading the CAD…

Real CAD · drag to rotate · scroll to zoomReal CAD · swipe sideways

Open risks we are working on

  • RS-485 and 5 V over a 10 m lead in a wet barn with a cow that chews cables: unproven; the lead runs on the gate rail in clips
  • 'Fresh cow has not drunk' needs a one-cow pen; in group pens the meter sees only the pen total
  • Stray-voltage readings depend on the ground rod and on wet or frozen floors; any amber or red reading means 'call an electrician', not a safety check
  • Pens without a bowl or trough get only the camera jobs; buckets cannot be metered
  • Lely Zeta and BETSY may add water inputs; Moocall needs no camera

Design stage only: nothing on this page is for sale. Specifications and prices are targets.