HeatCam
A replacement Android app for the Thermal Master P4 USB-C thermal camera, built for finding heat leaks and mould risk in a house.
Install
With Obtainium (recommended)
Obtainium installs the app and keeps it updated. Open this page on the phone and tap Add to Obtainium; the source, filter and version settings come along with it.
To add it by hand instead: in Obtainium tap Add app, enter https://heatcam.wibipedia.org/, choose source HTML under Override source, and set:
| Setting | Value |
|---|---|
| Custom APK link filter | heatcam-[0-9.]+\.apk$ |
| Version extraction regex | heatcam-([0-9.]+)\.apk |
| Match group to use | 1 |
Directly
Download the APK and open it; Android asks once to allow installs from your browser. You will not get update notifications this way.
Requirements
- Android 10 or newer with USB-C host (OTG) support
- Thermal Master P4 (USB
3474:42A1)
Plug in the camera and HeatCam offers to open. Allow Camera and the USB device access: Android treats the P4 as a camera and refuses USB access without the camera permission.
The screen
| Button | What it does |
|---|---|
| Mode | Cycles Image, Temp, Inside, Outside and Mould (below). |
| Palette / ΔT / Temps | Colour palette in Image and Temp; detection threshold (1, 2, 3 or 5 °C) in Inside and Outside; the indoor/outdoor temperatures and humidity in Mould. |
| View | Thermal only, Edges (outlines from the normal camera drawn over the heat map), Blend, or Camera. Long-press to align the two cameras. |
| Lock | Freezes the colour range so colours stay comparable while you move around. |
| Rotate | Turns the image a quarter turn. |
| Save | Stores what is on screen as PNG in Pictures/HeatCam, every pixel's temperature as CSV in Documents/HeatCam, and the camera photo when a camera view is on. |
Gestures
- Tap or drag to place a spot and read its temperature; long-press removes it.
- Double-tap switches between the whole image and filling the screen.
- The hottest and coldest points are always marked.
In landscape the buttons move to the side so the image uses the full height.
Inspection modes
Heat leaks are easiest to see when the outside is at least 10 °C colder than the inside, for example on a winter evening or morning.
| Mode | Use it | Shows |
|---|---|---|
| Image | anywhere | The camera's own contrast-enhanced picture. |
| Temp | anywhere | Colours by measured temperature, with a scale. |
| Inside | indoors, facing outer walls, windows, floors | Spots colder than the median of the view by at least ΔT: draughts, missing insulation, thermal bridges. |
| Outside | outdoors, facing the façade | Spots warmer than the median by at least ΔT: heat escaping. |
| Mould | indoors, on outer walls and corners | The temperature factor of each surface, red below the building-code limit. |
Mould risk
Mould mode needs the indoor and outdoor temperature (and optionally the indoor humidity); tap Temps to enter them. For each pixel it computes the temperature factor
f = (Tsurface − Toutside) / (Tinside − Toutside)
Below 0.65 (the Dutch limit, NEN 2778 / Bouwbesluit) a surface is at risk of mould; below 0.75 it is marked as a warning. With humidity set, the legend also shows the surface temperature at which mould can grow (80 % relative humidity at the wall) and the dew point, where condensation forms. The indoor and outdoor temperatures should differ by at least 5 °C for a reliable reading.
Normal camera overlay
The P4 has a second, normal camera. The Edges, Blend and Camera views use it to show what you are looking at. The two lenses sit apart, so align them once: long-press View, drag the heat map into place, pinch to resize, then tap Done. The alignment is remembered.
If the picture stops
HeatCam watches the stream. When no frame arrives for 3 seconds it restarts the stream, then reopens the connection, then resets the USB port, and only then asks you to unplug and replug the camera. Tap the message to try again right away.