SensingRev A design complete (stages 1-6), all hardware fit-checked in CAD, not built; UL 1069 accessory status is gate R1

CallNote

The call cord every nursing-home bed already has, made smart: the carer's phone gets the reason and a voice note, and the resident sees 'Help is coming'

A replacement call handset that plugs into the existing 1/4" nurse-call jack. Every key still calls the old way (dome light, station, tone). Each key also carries a reason (HELP, TOILET, PAIN, DRINK), holding a key records a short voice note, the right person's phone gets the reason, and the resident's e-paper screen says 'Help is coming' when a carer accepts. A handset that falls to the floor is reported. It adds information to a call; it never replaces the call system.

Who buys it: Directors of nursing and administrators of US nursing homes and assisted living on older 2-wire 1/4"-jack call systems (light and tone only). Today they use a $6-18 call cord; a new system costs about $450-3,000 per room.
Why it pays: Sending the right role with the right item saves an estimated 1.0-2.2 staff-hours a day on a 30-bed unit (est.), against $450-3,000 per room to replace the call system. The home also gets a response-time log for complaints and surveys.
Target price: $99 per handset + $4 per bed per month; Edge Hub $299 per site or shared (target)
First-minute wow: A resident holds TOILET and says 'I need to go now'; the aide's phone shows 'Room 7 · TOILET · I need to go now' while the old dome light comes on as usual, the aide taps Coming, and the handset buzzes and shows 'Help is coming'.

See the CAD design Concept page

CallNote 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

A call light says someone needs something, not what (toileting is the top reason) → 4 reason keys route TOILET and DRINK to aides and PAIN to the nurse, saving 1.0-2.2 staff-hours a day per 30 beds (CAD route report, est.)
Reason keys exist only on proprietary hospital pillow speakers (20-pin, 8-pin DIN) → CallNote uses the 1/4" plug older nursing-home systems and bed alarms already use, with a DIN adapter option
Residents get no feedback and staff forget to return (over 3% in a 4-home study) → 'Help is coming' on e-paper with a buzz, escalation if nobody accepts, re-alert if an accepted call is not closed
The call must never depend on new electronics → every key has its own plain loop switch beside the MCU switch; a flat battery leaves a working call cord
Call lights out of reach or on the floor are a common F558 finding → an accelerometer sees 12-21 samples of free fall from any bed height (CAD drop report) and tells the aide, plus a rail cradle
Voice-only assistants fail residents who cannot speak → keys first, voice optional, the clip always playable next to the transcript

Use case

Night shift on a 30-bed unit, 2 aides and 1 nurse

ResidentCare aideNurseDirector of nursing

01Trigger: at 02:40 Room 7 holds TOILET and says 'I need to go now'; the dome light comes on as before
02Detection: the handset's MCU switch gives the reason and records the note; the Edge Hub transcribes it on site
03Alert: the aide's phone shows 'Room 7 · TOILET · I need to go now'; the aide taps Coming and the handset shows 'Help is coming'
04Action: a PAIN call from Room 12 goes straight to the nurse, and a handset that slid to the floor in Room 4 is put back before it is needed

Outcome: The right role answers first with the right item, residents know help is coming, and the DON sees response times by reason (est.)

How it works

Architecture

01
Sense: 4 keys with 2 switches each (loop + MCU), PDM mic, LIS3DH accelerometer, battery voltage
02
Decide: the XIAO ESP32-S3 sets the reason, records a held-key note and detects a drop; the Edge Hub applies routing and escalation rules
03
Send: the old loop calls as before; Wi-Fi MQTT/TLS to the site Edge Hub, audio stays on site, the cloud gets counts and device health only
04
Tell: carer phone alerts with reason and clip/transcript, the handset's e-paper and buzz, and a weekly response report for the DON

Hardware

Real parts, buyable today

Bill of materials: about $62 per handset at qty 1, about $30 at qty 1,000 (est.).

Block	Part	Why this part
MCU + mic	Seeed XIAO ESP32S3 Sense (camera not fitted)	Wi-Fi, PDM mic, PSRAM for a 10 s clip, about 14 µA deep sleep (est.)
Keys	8 x Omron B3F tact switches under a 1-piece TPU keypad	Two switches per key: one closes the old loop, one tells the MCU
Feedback	Waveshare 1.54" e-paper + coin vibration motor	'Help is coming' stays on screen with no power
Drop sense	Adafruit LIS3DH	Free-fall interrupt; 12-21 samples from any bed height
Power and cord	1800 mAh LiPo + 2.4 m cord with Switchcraft 280 1/4" plug	110-560 days per charge (est.), same plug as the cord it replaces

Mechanical

Printable CAD

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

See the CAD parts render

CallNote printable parts, rendered from the CAD — Render of the printable parts from the actual CAD. Not yet printed or photographed.

Loading the CAD…

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

Open risks we are working on

UL 1069: a third-party cord may affect a listed system, and some states require listed components (gate R1: NRTL and 3 AHJs)
FDA classification [UNVERIFIED]: nurse-call products use IQA, OUG or KMI codes (gate R2); no fall or outcome claims
Not every 1/4" system is a simple contact (resistor-coded or cord-out jacks); test 5 systems (gate G2)
Rauland, Hillrom/Baxter, Tektone and Ascom sell reason keys on new systems; our window is the old system's remaining life
Voice clips are PHI; staff may see response reports as surveillance (unit-level by default, gate G3)
No director-of-nursing interviews yet (gate G1: 10 interviews + a 2-week unit pilot)

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