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Short answer: the TOPDON TC001 Plus is the Android thermal camera to buy for real diagnostics, with a 256 x 192 native detector, a visible camera with fusion and nine measurement areas; the FLIR ONE for Android is the pick for a homeowner who wants MSX and the guided inspections of the FLIR ONE app, on an 80 x 60 detector that the listing upscales to 240 x 180; and the Thermal Master P1 is the value pick that states 25 Hz, 40 mK and a 5 to 8 hour draw at 0.62 oz, on a 160 x 120 detector sold under a 320 x 240 X3 headline.
The Android USB-C field
Android was the first home of the plug-in thermal module because the platform allowed USB accessories early, and most of the current modules are Android-first or Android-only. The listings are specific about it: the TOPDON TC001 Plus, TC001 and TS001 and the Thermal Master P4 state Android and Windows and exclude iOS, with the TC001 adding that it is not compatible with iPhone 15. The TC002C Duo, TC001 Max and Thermal Master P1 are USB-C modules that state Android alongside iOS and Windows. The FLIR ONE for Android is USB-C Android only. Two requirements come up repeatedly in the TOPDON text: the phone must support OTG, and the TISR upscale runs only on phones that can process it. Neither is exotic on a current Android phone, but both are worth checking on the manufacturer compatibility list before buying, and the smartphone thermal camera guide covers how.
Three detector classes
The modules in the table fall into three native classes, and the class matters far more than the headline figure. The 256 x 192 class, 49,152 pixels, is the TOPDON TC001 Plus, TC001 Max, TC001, TC002C Duo and TS001 and the Thermal Master P4; the TOPDON listings describe 512 x 384 as TISR output and the P4 listing describes it as super resolution. The 160 x 120 class, 19,200 pixels, is the Thermal Master P1, whose listing title says 320 x 240 but whose text describes X3 technology upgrading a 160 x 120 detector; the RISION Magic in our smartphone guide is the same class. The 80 x 60 class is the FLIR ONE for Android, upscaled to 240 x 180 by Vivid IR. From a few feet away all three classes show a warm breaker or a cold draft; from across a room, only the 256 x 192 class resolves a stud bay or a duct run with a defined edge.
Sensitivity, refresh and the figures TOPDON does not always state
NETD in millikelvin, lower being better, and refresh rate in Hz are the two figures that describe how a module behaves in use rather than on paper, and they are stated unevenly. The Thermal Master P4 states under 35 mK, the P1 states 0.04 C, which is 40 mK, and the TC001 Max and TC002C Duo state 40 mK; all of those state 25 Hz, as does the TS001. The TC001 Plus and TC001 listings state neither, despite sharing the 256 x 192 detector class with the modules that do, and the FLIR ONE for Android states neither. That leaves a buyer comparing the TC001 Plus, which states the most measurement features, against the TC001 Max, which states NETD, refresh and Lightning support, and the P4, which states the lowest NETD of the group and an IR Eraser swipe view that reveals the visible image under the thermal one. Our TOPDON TC001 Plus review and TS001 review go through the individual modules.
The second lens
A thermal image on its own is a field of color with no edges, and on a phone screen that is hard to interpret. The modules that add a visible camera fix that: the TC001 Plus and TC001 Max carry a second lens and fuse the two images, the P4 does the same and adds IR Eraser and 15x digital zoom, and the FLIR ONE for Android uses MSX, which embosses visible edges onto the thermal picture. The TC001 achieves fusion with the phone camera instead of a built-in lens, which works but depends on the phone camera being aligned with the module. The P1 and TC002C Duo have no visible camera at all, which keeps them light and simple; the P1 is 0.62 oz and the TC002C Duo 1.1 oz. For a technician documenting a finding, the second lens is worth having. For a homeowner hunting a draft, it is optional.
Power, cables and cases
Every plug-in module here runs on phone power, and the listings that state a draw are consistent: Thermal Master states 0.32 W for 5 to 8 hours on the P1, TOPDON states 0.35 W for 4 to 7 hours on a 3000 to 5000 mAh phone for the TC001 and TS001, and the P4 states up to 5 hours. Cables matter because a module on the end of a 19.7-inch cable, which the TC001, TC001 Plus and TS001 include, can be pushed behind a water heater or above a ceiling tile while the phone stays in hand, and a 50 cm cable ships with the P1. TOPDON states the TC001 Max works without removing most phone cases. Accuracy figures come with conditions: TOPDON states within 3.6 F or 2 percent, Thermal Master plus or minus 3.6 F, and FLIR plus or minus 3 C or 5 percent only within a stated ambient and scene range.
Emissivity and what an Android module cannot see
A phone module reads surface temperature and nothing behind it. Shiny metal reads low because its emissivity is low and it reflects the room, so a bare copper line, an aluminum window frame or a stainless panel shows cold and may carry a warm reflection of the person holding the phone. The P1, P4 and RISION apps state adjustable emissivity; set it for the surface, or read a strip of tape on the metal instead. Step sideways to tell a reflection from a defect.
Related guides
The full cross-platform table, including the wireless FLIR Edge Pro and the Seek modules, is in the smartphone thermal camera guide; iPhone owners should read the iPhone thermal camera guide, which handles the Lightning and USB-C split.
