Skip to content
IEMI Labs
All product designs
HomeRev B design complete (stages 1–6), not built; rev A survey kit unchanged

MouldGuard DryBase

The dehumidifier you already own, made smart: it runs on the cold wall, not the dial, and weighs every litre it pulls out

Turns the family's own dehumidifier into one that keeps the coldest wall below condensation risk, logs the litres it removes every day, says when the tank is full, and says plainly when a wall is too cold for drying to fix. The rev A survey kit stays for surveyors.

Who buys it
Families in damp homes (UK first); social landlords under Awaab's Law lending it under the tenant's own dehumidifier; damp and mould surveyors keep the rev A kit.
Why it pays
Less wasted running on warm walls and no lost nights to a full tank (est.); for a landlord, a record that separates "the drying is working" from "this wall is too cold" before a repeat visit (~£800, assumed) or a disrepair claim.
Target price
DryBase £119 with the Shelly plug, £99 without (target; hardware about $90 / $65 at qty 1, est.). Rev A survey kit £399 / $499 + £15 / $19 per month, or £60 / $75 rental
First-minute wow
On a 12 °C wall the usual 50% dial leaves the wall surface at 83% humidity (mould) while an 18 °C wall is over-dried by 12 points: DryBase runs the unit on the wall, and the scale shows the litres it really pulled out.
See the CAD designConcept page
MouldGuard DryBase 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

  • Rev B: the survey kit was an attachment the family never owns → the dehumidifier they already have becomes the product, with nothing opened or wired in
  • Dehumidifiers run on the room-humidity dial → a wall tag (SHT45 + surface NTC) keeps the coldest wall at or below 70% surface RH
  • Units stop silently when the tank is full → a weighing board sees the plateau and the plug sees the power drop; the phone is told in minutes
  • Nobody knows how much water is coming out → litres per day and per kWh from 4 load cells and the plug's meter
  • Drying cannot fix a wall that is too cold → the hub says "needs heat or insulation" instead of running the unit flat out
  • Rev A: Switchee (£99) and Aico own the permanent fleet → a reusable 4-node investigation kit, about 20 jobs a year per kit
  • Rev A: Room pucks miss the cold wall → contact NTC wall probe; the cloud computes surface RH and dew-point margin
  • Rev A: Spot meters (Protimeter MMS3 £689 ex VAT) don't log → two-pin moisture probe logs every 30 min, calibrated against an MMS3
  • Rev A: Weak US regulatory pull → floor leak pad and dry-out verification sold on money, not law
  • Rev A: Evidence can be challenged → signed hash chain, moved/tamper flags and placement photos in every report

Use case

A bedroom wall that a dial could not protect

FamilyTenant's landlord (with consent)DryBase hub

  1. 01Trigger: black spots return on a bedroom corner although the dehumidifier runs on 50% every night
  2. 02Detection: the wall tag reads a 12 °C surface; at 50% room RH the wall sits at 83% surface RH
  3. 03Alert: the hub runs the unit on the wall, logs 3.1 L/day, and after 3 nights flags "this wall needs heat or insulation"
  4. 04Action: the family shares the weekly page with the landlord, who starts an Awaab's Law investigation with the data

Outcome: Less wasted running, no lost nights to a full tank, and a dated record that the wall, not the family, is the problem (est.)

How it works

Architecture

  1. 01

    Sense: 4 x 50 kg cells under a board (water pulled out, tank full, emptied); wall tag with SHT45 + surface NTC; plug power

  2. 02

    Decide: XIAO ESP32-C6 hub computes wall surface RH every 60 s and switches the unit with on/off minimums for the compressor

  3. 03

    Send: home Wi-Fi to the Shelly plug (local API) and phone push; no cloud needed

  4. 04

    Tell: e-paper on the hub, phone alerts, a weekly page the tenant can share

  5. 05

    Rev A survey kit: Sense: SHT45 room RH/T, contact NTC on the coldest wall, two-pin moisture probe, floor leak pad, accelerometer for moved flags

  6. 06

    Rev A survey kit: Decide: nRF9151 logs every 10 min and signs a hash chain; the cloud computes surface RH, dew margin and pattern hints

  7. 07

    Rev A survey kit: Send: LTE-M/NB-IoT hourly batches, leaks immediately; no gateway, no Wi-Fi

  8. 08

    Rev A survey kit: Tell: surveyor app, SMS on leak, signed PDF evidence report and read-only landlord link

Hardware

Real parts, buyable today

Bill of materials: DryBase about $90 with the plug at qty 1, about $65 without (est.); rev A kit about $344 (est.).

BlockPartWhy this part
Weighing board4 x SparkFun SEN-10245 class 50 kg cells + HX711, under 420 x 320 x 12 plyAbout 0.8 g noise after 1 min (est.); 0.3 mm overload stop at 1.2 x FS per cell
Wall tagSensirion SHT45 + TDK B57861S NTC beadAir beside the wall plus the wall surface gives surface RH directly
HubSeeed XIAO ESP32-C6 + Waveshare 1.54" e-paperWi-Fi to the plug; shows wall risk, litres today, tank state
SwitchShelly Plus Plug UK (listed, power metering)Switches the dehumidifier with no wiring; power gives tank-full and litres per kWh
MCU + modemNordic nRF9151 SiPLTE-M + NB-IoT, hardware key storage for signing
Room climateSensirion SHT45±1 %RH keeps surface-RH error near ±3–4 %RH
Wall surfaceTDK B57861S0103F040 10k NTC in a printed clipContact reading of the coldest corner
Wall moisture2 stainless pins + TI LMP7721 bufferLogs WME-style resistance from 1 MΩ to 10 GΩ
Power2 × Energizer L91 + TI TPS63802About 250 days per cell pair (est.); cells sold everywhere

Mechanical

Printable CAD

13 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
MouldGuard DryBase 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

  • Meaco already has app tank-full alerts and could add a wall probe
  • Auto restart after power loss varies by model; non-restarting units are monitor-only
  • The wall tag may warm the spot it measures (test T-B2)
  • No family or landlord interviews yet (gate G-B1)
  • Rev A: UK surveyors may not buy or partner; run the 30-day LOI test first
  • Rev A: Pin-probe moisture accuracy without a proprietary calibration
  • Rev A: UK LTE-M roaming and PSM current not yet measured
  • Rev A: Thin hardware margin at £399; the business depends on subscriptions and rentals

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