Lego Sherlock Holmes figure focuses a light beam on a Lego criminal with a small magnifying glass.

Multispectral Rover

Rover equipped for imaging in two spectral ranges

I've recently become a big fan of the OpenMV camera, as, for example, my post on "LEGO Selfie Machine". Things got even more interesting when I found that the OpenMV imaging module can be swapped out for a FLIR Lepton to work with thermal imaging. Thermal imaging has been in the past too expensive to play with, but the FLIR Lepton makes the cost reasonable ($200 for the imaging module plus $15 for the OpenMV adapter--see The pixel resolution is part of the low cost at only 60 x 80 pixels, but this is good enough for interesting projects. So, as in the photo above, I mounted the thermal imaging on a LEGO rover. In addition, I also installed a visible camera in the form of a Mindsensors Vision Subsystem V5 ( An ultrasonic sensor detects when an object comes within a specified distance, then the EV3 brick produces a digital logic trigger for both cameras. I wanted to use the rover outdoors, so I used tank treads driven by a pair of EV3 Large Motors. The tank treads and chassis are from a Technic 42094 Tracked Loader set, which I motorized with the EV3 motors. This kit's tread design includes a spring suspension, which seems to help in driving outdoors. Example outdoor driving performance is in the video below.

The Multispectral Rover has obvious security applications for mobile surveillance. The thermal imaging is quite effective at detecting people that come into view. But it also works well with animals. I parked the rover at a water fountain that squirrels sometimes visit for a drink. An example result is below. In this case, I had removed the short wave infrared filter (at 700-1100nm range, not to be confused with the thermal infrared of the FLIR Lepton) installed in the Mindsensors camera, because I was working with supplemental infrared lighting. This lack of an IR filter is why the visible image of the squirrel looks a little washed out. Experiments are continuing. The cameras can also take videos. I'm considering next to swap out the Mindsensors camera with a visible camera OpenMV and switching to all-Python control software for the EV3, as well as the OpenMVs.

a squirrel viewed in both visible and thermal infrared wavelengths