CAT S61 Android smartphone review: Taking the smartphone as a tool to the next level

An advanced thermal imaging camera, a laser distance tool, and an air quality monitor are all tools of the trade for the enterprise. With the Cat S61, these tools are found in an Android smartphone that lets you also do all that a smartphone can in a single rugged tool.
Written by Matthew Miller, Contributing Writer

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Earlier this year I took a look at the Cat S41 rugged smartphone. It's more advanced big brother, the Cat S61 was announced a few weeks later at MWC and I've spent the last few weeks testing out its three cool tools.

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The Cat S61 includes an integrated thermal imaging camera, laser assisted distance measuring tool, and an indoor air quality monitor all in one device. The Android smartphone offers a stock experience with the latest software and security update while skipping carrier bloatware as it is offered as an unlocked GSM device. It will both turn heads and get the job done.


  • Processor: Qualcomm Snapdragon 630 octa-core 2.2 Ghz
  • Display: 5.2 inch 1920x1080 pixels resolution Gorilla Glass 5
  • Operating system: Android 8 Oreo (Committed upgrade to P)
  • RAM: 4GB
  • Storage: 64GB internal with microSD card slot
  • Cameras: 16 megapixel with phase detection auto focus. Front 8 megapixel camera. FLIR Lepton lens above the rear camera.
  • Battery: 4500 mAh with Quick Charge 4.0 fast charging
  • Water resistance: IP69 and MIL-STD 810G shock and drop resistant, waterproof up to 3 meters for 60 minutes
  • Wireless connectivity: FM radio, 802.11 b/g/n WiFi, NFC, Bluetooth 5, GPS, Glonass, BeiDou, Galileo
  • Sensors: Thermal, indoor air quality (humidity and temperature), compass, proximity, accelerometer, gyro, barometer
  • Dimensions: 163 x 78 x 13 mm and 250 grams


When I head out into a shipyard, go on a marine vessel to aid with salvage, go on a hike to the mountains, or hit up a local river for fly fishing it is routine to wrap my smartphone in some kind of rugged case. This adds bulk to my phone so that when I compare my wrapped phones to the new Cat S61 there is not much difference in size between them.

While the Cat S61 is a bulky phone, Bullitt Mobile has done a great job making it look and feel great with aluminum edges and raised housing for the FLIR camera, soft touch silicone material on the back for excellent handling, buttons that are easy to find and press, and port covers that stay in place securely. Overall, the phone looks like it means business and the features prove that it does.

On the front we have the 5.2 inch display with a wide top bezel and substantial side bezels. When you are wearing gloves and operating the phone, this makes sense. There are three hard plastic physical buttons below the display for back, home, and task switcher. The buttons are large enough to easily press with a gloved finger and they have excellent tactile feedback too.

At the bottom we have a USB-C port for charging and a mono speaker. It's great to finally see the move to USB-C as microUSB cables move out of my collection. The bottom speaker is very loud and if the Cat S61 had a sound meter in it I bet it would likely best the Huawei P20 Pro that has a speaker with a reported 91dB output. A loud speaker is important when working in the field where you may have hearing protection on and where the ambient environment may be filled with operating machinery.

The power button is found at the top of the right side with ridges to make it easy to find without looking. The two volume buttons are below this with the openings for the air quality monitor just below halfway down the right side.

A large metal door covers the microSD and SIM card slot on the upper left hand side. Below this is an orange programmable button that has traditionally been assigned as a push-to-talk button. You can customize what the button does with a short press or a long press so I have it set to launch the Google cards and MyFlir camera.

Another small metal cover protects the standard 3.5mm headset jack found on the top next to the raised area where the FLIR camera is located.

Around the back we have the FLIR camera in the upper left with the 16 megapixel camera below it and a flash light centered under this camera. Down at the bottom left we have the laser light that is used to measure the distance of objects from 0 to 8 meters away.

The Cat S61 has IP68 and IP69 dust and water resistance so it can handle most environments. It is also rated to handle environments from -25 to 55 degress Celsius, but don't put it in the freezer or the oven to test this out.

CAT S61 Android smartphone review: in pictures

Advanced tools

Let's take a bit deeper dive into the three major tools we have on the CAT S61; the thermal imaging camera, the air quality meter, and the laser measuring device.

The CAT S60 also had a thermal imaging camera, but on the S61 we see the temperature range expanded along with higher resolution support. It can help you locate a heat source up to 400 degrees Celsius. There are a number of color palettes you can choose from to see the hot or cold spots in different color schemes.

You can also capture a photo, record a video or create a time lapse with the MyFLIR app. A temperature scale can be shown on the right side so you can check heat and cold ranges in real-time. A high temperature mode extends the camera sensor range up to the 400 degrees, but it has a bit less accuracy. If you are seeking heat less than 120 degrees Celsius then don't use this high temperature mode.

The thermal imaging camera cannot see through walls, but there are a ton of practical uses. For example, you can detect heat loss around windows and doors, identify "hot" electronics and circuits, or find leaks in pumps or other devices with cold liquids. The camera does "see" through smoke so you can use it to escape from a fire by plotting a route free from high temperatures.

There is also a YouTube Live option, which can be useful for field workers who are out capturing data and want to feed it back to engineers or technicians for live troubleshooting of various situations.

Sometimes we work in environments that may appear benign, but can lead to trouble. The indoor air quality meter measures temperature, humidity, and the level of volatile organic compounds (VOCs) in your environment. When you work in a shop, enter a paint locker, or get work done on a construction site there can be some hazardous environments where more ventilation is needed and that is where the S61 can help you out.

VOCs are commonly associated with solvents, paint, glue, and cleaning agents. The sensor in the S61 checks air quality every four seconds and can alert you when an unhealthy level is reached. Keep in mind, this is not designed for checking to see if adequate oxygen is available or whether carbon monoxide is present so know the tool and use it to help you evaluate your workspace.

The laser measuring tool uses the laser and the rear camera together to calculate distances. You use both to first calibrate the S61 and then you can start measuring distances up to 8 meters. The rear camera will attempt to auto capture the laser, but you can also tap on the dot if that isn't working reliably. You can also use it to help calculate areas, which is good for estimating material for a job.


The Cat S61 runs Android 8.1 with the June 1, 2018 security update currently installed. Bullitt Mobile has promised to upgrade it to Android P as well so we may expect to see this update before the end of the year.

The experience is very much like stock Android with a Google launcher. There are a few Cat apps preinstalled, such as an app toolbox (store front), camera, file browser, measure, MyFLIR, and air quality.

The phone also has underwater mode, which can be activated by triple pressing the power button or selecting the option from within the camera app. This mode locks the touch screen and allows you to capture pictures or videos underwater using the volume keys. This is a great feature I would like to see on all of these phones that people use underwater since water often causes inadvertent screen activation on other phones.

The camera app is very basic with options for underwater mode, panorama, video, and still photos. There are several filter options, HDR toggle, and a few other basic options in the settings.

Pricing and availability

I haven't found another phone to challenge the Cat S61 directly and it truly stands apart with these advanced field tools. Handheld thermal imaging cameras can be found from $400 to more than $2,000, but the lower priced ones do not have the vast temperature range seen on the Cat S61. Air quality monitors with similar functionality range from $80 to $200. Laser measuring tools can be found from $50 to more than $200. Add the cost for these three tools and the lowest cost for this functionality, not even equivalent to the S61, is $530. Thus, for $1,000 you get a capable Android smartphone and three advanced tools in a single handheld device.

Daily usage experiences and conclusions

The Cat S61 smartphone is not designed to compete with the Apple iPhone, OnePlus 6, Galaxy Note 8, or any other typical high end or mid-range smartphone. You should only consider buying the S61 if your company has a need for thermal imaging technology. If you just want a rugged smartphone with no need for thermal imaging, then take a look at the Cat S41 for $450.

The battery easily lasts me a couple of days, the processor has never let me down, phone calls sounded great and connectivity with T-Mobile was solid, the buttons are easy to find and manipulate, and I had a great time testing all of the tools.

I am currently managing a team of surveyors and engineers working in a shipyard and the Cat S61 would be a great tool for them with the thermal imaging camera useful for the electical inspector, the laser measuring tool for the structural and piping inspectors, and the air quality sensor useful to all working in an environment with paint, high humidity, and other potentially hazardous liquids. There is clearly a market for devices like the Cat S61 and the $999.99 price is not a deterrent.

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