Skip to content
IEMI Labs
All product designs
VisionRev B1 design complete (ClearZone added 26 Oct 2026), not built; rev A camera add-on unchanged

PoolGuard Latch

The pool gate you already have, now telling you when it didn’t close or something is against the fence

Measures every close of an existing self-closing, self-latching pool gate (home / bounced / stalled / propped) and warns from the close-time trend that the hinge springs are weakening. ClearZone camera pods on the fence posts watch the 900 mm strip outside the fence and send a photo when a chair, pot plant, esky or toy has been left there. Camera after-hours entry alerts remain an optional add-on for commercial pools.

Who buys it
Families with a backyard pool (US/AU); apartment, HOA and hotel pool managers; pool fence installers as the sales channel.
Why it pays
Replaces finding out by eye that the gate stands open; for commercial pools, a self-latch failure is a major health-code violation that can close the pool (est. days of lost amenity plus liability exposure), and the log replaces a paper walk-round.
Target price
Latch Kit $79; ClearZone pod $69; Fence Kit (Latch Kit + 2 ClearZone pods) $199; Smart Latch bundle (MagnaLatch S3 + kit) $169; commercial gate log $4/gate/month (targets). After-Hours camera add-on $2,190 + $49/month
First-minute wow
A photo on the phone: “Something is against the pool fence, east side”, with the kids’ ride-on car boxed in the strip. Three weeks later: “Gate A is closing 19% slower than when fitted. Adjust the hinge springs.”
PoolGuard Latch 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 camera kit was an attachment next to the barrier → the gate itself now reports every close, on any latch brand, with nothing opened or modified
  • The gate is where barriers fail (21 of 32 investigated fenced pools: faulty gate or latch) → HOME / BOUNCED / STALLED / PROPPED result for every close, with a phone alert
  • Climbable objects left by the fence are the other top inspection failure (Royal Life Saving WA; Auckland: 25% fail first inspection) → rev B1 ClearZone pods photograph the 900 mm strip 6 times a day and alert on a new object still there after 20 min
  • Hinge springs weaken silently and gates stop latching from part-open → a weekly close-time trend warns at +15%
  • MagnaLatch ALERT only beeps at the gate → phone alert, gate chirp and a log for inspectors and insurers
  • Life-safety liability → no drowning, barrier or compliance claim; the fence and the listed latch stay the barrier

Use case

The ride-on car parked against the fence

ParentPool fence installer

  1. 01Trigger: after school a child leaves a ride-on car and a stacking chair against the outside of the pool fence
  2. 02Detection: the 4 pm ClearZone photo shows two new objects in the 900 mm strip; 20 minutes later they are still there
  3. 03Alert: the parent’s phone shows the photo with both objects boxed: “Something is against the pool fence, east side”
  4. 04Action: the parent moves them and taps “fixed”; the next photo is clear and the log shows the time it took

Outcome: The strip is cleared the same afternoon instead of at the next inspection, with a dated record

How it works

Architecture

  1. 01

    Sense: LeafPod on the gate leaf (gyro swing angle, Hall gap to the PostTag magnet); ClearZone camera pods on fence posts; optional rev A cameras

  2. 02

    Decide: on-device close classification and spring trend; on-device change map of the zone strip with a person/animal filter and a 20-minute still check

  3. 03

    Send: home Wi-Fi, or the rev A PoolPost / IEMI Edge Hub at commercial pools, over outbound MQTT/TLS

  4. 04

    Tell: phone alert with a photo or close result, gate chirp; weekly gate health and an inspection-ready log

Hardware

Real parts, buyable today

Bill of materials: about $43 per Latch Kit and about $39 per ClearZone pod at qty 1 (est.); After-Hours camera add-on about $805 per pool (est.).

BlockPartWhy this part
LeafPodSeeed XIAO ESP32C3 + Adafruit LSM6DSOX + TI DRV5055A4 linear Hall + 2 x AA lithiumSleeps until the gate moves; about 2.4 years on 2 AA (est.); measures the gap to 0.08 mm
PostTagN42 Ø12.7 x 6.35 mm magnet in a printed holderPassive, on the latch post; no wiring
ClearZone podSeeed XIAO ESP32S3 Sense (OV2640) + Pololu S7V8F3 + 2 x AA lithium, on a 12° post wedgeLooks along the fence 25° down; a 0.45 m chair 10 m away is 48 pixels tall; about 700 days per battery set (est.)
Bundle latchD&D MagnaLatch Series 3 Top Pull, unmodifiedThe listed latch stays the barrier
Add-on: HubIEMI Edge Hub: Raspberry Pi 5 8GB + AI HAT+ 26 TOPS (Hailo-8) + UPSReused platform, indoors on mains; nothing mains-powered at the pool
Add-on: CamerasReolink RLC-510A PoE + printed polariser hoodONVIF, IP66, $40–59; polariser cuts surface glare
Add-on: PoolPostOlimex ESP32-POE + TL-POE10R 12 V splitter + MAX98357A + horn + strobeOne PoE cable, low voltage, works with the internet down
Add-on: GateWired N/C reed switch with 10 kΩ end-of-line resistorDetects open, propped and cut wire
Add-on: Lifeguard band (phase 2)Seeed XIAO nRF52840 + coin motor + 150 mAh LiPoBLE buzz for supervised pilots only

Mechanical

Printable CAD

16 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
PoolGuard Latch 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

  • D&D Technologies already sells the MagnaLatch ALERT and could add Wi-Fi
  • Generic cameras (Ring, Arlo, Eufy) could add a “still object in zone” feature in software
  • ClearZone accuracy with shadows, wind-blown plants and dew on the window is untested (T-Z1, T-Z2)
  • A boundary-fence camera must not look into the neighbour’s yard; the strip mask needs checking for privacy
  • Whether “latched” (not just “home”) can be sensed from outside the latch is untested (T-B3)
  • Weak Wi-Fi at the fence line in many backyards
  • Buyers may treat a gate or zone monitor as a barrier, compliance check or drowning-prevention device despite the wording
  • Add-on: Buyers or plaintiffs may treat an entry alert as drowning prevention despite the wording

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