Skip to content
IEMI Labs
All product designs
SensingRev A design complete (stages 1-6), all hardware fit-checked in CAD, not built; Leapfrog accepts 'activity monitoring' systems but the hospital must validate them, and acceptance of unit-level feedback is unconfirmed

RubDock

The hand-rub dispenser at the room door, made smart: it counts every rub, knows when it will run empty, and reports rubs per room entry with no badges, cameras or names

A thin Dock screws into the dispenser's old wall anchors and the ward's own dispenser screws onto it, hanging on a load cell, so every rub shows up as about 1 g leaving the scale. A DoorTally stuck on the door jamb counts people in and out with a two-zone time-of-flight sensor. The ward gateway reports rubs per room entry by unit and shift and sends a refill list before dispensers run empty. It counts and reports only: it does not prove hands were cleaned and makes no infection claim.

Who buys it
First: infection prevention teams at US hospitals meeting Leapfrog's standard of 200 hand hygiene opportunities per unit per month, where about 90% still use human observers. Then: care homes that must audit hand hygiene and cannot afford badge systems. Today they pay for auditor time or about $450-650 per bed per year for electronic monitoring.
Why it pays
Covert observers measured 50% compliance where hospitals' own auditors reported 84%, so a full count is worth more than 200 watched opportunities. RubDock targets about $48 a year in fees per room against $450-650 per bed per year for electronic systems (est.), and turns empty dispensers, the most common dispenser fault, into a planned refill list.
Target price
$179 per room kit (Dock + DoorTally) + $4/room/month; Dock alone $99 for refill alerts (target)
First-minute wow
The unit report on Monday: 9,300 room entries and 5,100 rubs at the door last week, night shift at 41%, and three dispensers that sat empty all weekend, with no badge on anyone and no camera in the corridor.
RubDock 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

  • Human observers are biased (covert 50% vs auditor 84%) and Leapfrog wants 200 opportunities per unit per month → every entry and every rub is counted on every shift, and the export gives the opportunity count
  • Staff dislike badges (78% think they are inaccurate; unions object to surprise monitoring) → nothing is worn, nothing identifies anyone, and rooms are only shown once they have 20+ entries
  • Electronic systems cost $450-650 per bed per year and lock you into one brand's dispensers → a scale behind any dispenser, $179 per room plus $4 a month (target)
  • 27% of dispensers in a German audit were defective or unusable, mostly empty → the Dock knows grams left and sends a refill list sorted by predicted empty time
  • Only 20% of dispensers gave full volume on the first push, so push counts mislead → rubs are counted as mass steps, which also gives grams per rub
  • ST's overhead people-counting layout covers only 17-36% of a 1.12 m door at body height (CAD report) → the DoorTally sits on the jamb at 1.25 m and sees every crossing point

Use case

A medical ward replaces monthly observation

Infection prevention nurseWard managerEnvironmental services

  1. 01Trigger: Leapfrog asks for 200 opportunities per unit per month and the ward's one auditor reports 88%
  2. 02Detection: 28 Docks behind the existing door dispensers and 28 DoorTallys log 9,300 entries and 5,100 rubs within 15 s of an entry in a week
  3. 03Alert: the unit report shows 55% overall and 41% on nights, and three dispensers empty all weekend
  4. 04Action: environmental services adds those rooms to the Friday refill run, and the night huddle sees the unit trend with no names

Outcome: A full count every shift instead of 200 observations a month, and about 11 auditor hours a month back (est.)

How it works

Architecture

  1. 01

    Sense: a 5 kg bar load cell behind the dispenser, weighed every 10 s; a two-zone VL53L1X on the jamb woken by a PIR

  2. 02

    Decide: weight drops become rubs per 10 s bin; the gateway counts a rub 'at entry' within 15 s of an IN at that door

  3. 03

    Send: ESP-NOW to a ward gateway, then counts only over MQTT/TLS; no images, no IDs, no hospital Wi-Fi on the devices

  4. 04

    Tell: a weekly unit report by shift, a Leapfrog opportunity export, and the environmental-services refill list

Hardware

Real parts, buyable today

Bill of materials: about $43 per Dock + $52 per DoorTally = $95 per room at qty 1, about $45 per room at qty 1,000 (est.).

BlockPartWhy this part
WeighingSparkFun SEN-14729 TAL220B 5 kg straight bar + HX711A half push (0.34 g) is 10x the averaged noise and a full push 30x (CAD dose report, est.)
Door counterPololu #3415 VL53L1X carrier + Panasonic EKMB PIRTwo ROI zones give direction with no image; the PIR keeps it asleep between passers
MCU + radioSeeed XIAO ESP32-C3 (one in each unit)ESP-NOW long range, 44 uA sleep, Li-ion charging over USB-C
Power2 x 18650 in the Dock, 1 x 18650 in the DoorTallyAbout 184 and 157 days per charge (CAD power report, est.)
MechanicsPrinted PETG Dock with a floating hanger on 0.6 mm stop pinsAll weight goes through the cell (0 mm3 contact in CAD); hard pushes land on the pins at about 7.5 kg (est.)

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
RubDock 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

  • Rubs per entry is a proxy: in/out counting sees about a third fewer opportunities than the WHO 5 moments, and visitors count as entries; reported as a trend, never as compliance
  • Leapfrog accepts activity monitoring but the hospital must validate it, and whether unit-level feedback meets 'feedback to individuals' is unconfirmed (gate G2)
  • GOJO, Ecolab and Deb own the dispenser contracts and could bundle monitoring with refills or refuse third-party plates
  • Load-cell creep under a constant 1.8 kg, dispenser hole patterns and printed 0.6 mm stops are untested (T1, T2)
  • Pairs walking side by side, beds and carts, and doors held open may miscount (T3); ESP-NOW range through ward walls is unmeasured
  • No infection prevention or care-home interviews yet; gate G1 is 5 hospital teams and 3 care homes

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