This week's EYE ON NPI is 🔥hot Hot HOT! We're doing another temperature sensor this week, but this time it's the opposite of a remote Infrared sensor (https://blog.adafruit.com/2025/07/03/eye-on-npi-melexis-mlx90632-miniature-far-infrared-fir-sensors-eyeonnpi-digikey-adafruit-melexis_sensors/): we're covering the Omega Engineering SA1 Series Self-Adhesive Polyimide Fast Response Surface Thermocouple (https://www.digikey.com/en/product-highlight/o/omega-engineering/sa1-series-self-adhesive-polyimide-thermocouple) a high quality thermocouple with integrated U-shaped self-adhesive backing that ensures a secure fit on various surfaces and is designed for quick and easy installation.

Last week we talked about how to measure the temperature of something without touching it (https://blog.adafruit.com/2025/07/03/eye-on-npi-melexis-mlx90632-miniature-far-infrared-fir-sensors-eyeonnpi-digikey-adafruit-melexis_sensors/), this week we're going to talk about a thermocouple sensor that gets all-up-in-your-personal-space. Why not use a remote sensor? For one, the temperature range is limited: it'll only do up to 200 C, and you need to make sure you have a good close view. Thermocouples are rugged and can easily handle up to and beyond 750 C (https://www.dwyeromega.com/en-us/resources/k-type-thermocouples). They can also be many meters away: their thin wires make it easy to snake into a kiln, or HVAC system. Traditional thermocouples come with just a welded-wire tip (https://www.digikey.com/short/0tttrf8v), or sometimes an encased metal-tip probe (https://www.digikey.com/en/products/detail/omega/SICIN-125G-6/25633429). The latter is good for sticking into fluids or tanks.

However, sometimes you want to measure the surface of something like a pipe or plate. Particularly since using a thermocouple implies a wide temperature range, you'll need something better than packing tape. The Omega SA1 Series comes with a 1"x0.75" adhesive pad made of fiberglass, polyamide and silicone glue (https://assets.omega.com/manuals/test-and-measurement-equipment/temperature/sensors/thermocouple-probes/M0503.pdf) that is good up to 177 C. Note that this is below the max rating of a thermocouple, so it's good for remote monitoring of many surfaces but you can't stick it to the inside of an oven and expect it to stay in place.

Right now DigiKey is stocking the popular K-Type version (https://www.digikey.com/short/jj30553m) of the SA1 series, but the J, T, E, and M variants are also available for special order (https://www.digikey.com/short/0rw070wd). K-Type tend to be the best supported thermocouple variant, don't forget you'll also need a chip or ADC that can read the millivolt differentials on the thermocouple wires (https://it.omega.com/temperature/pdf/Type-K-Thermocouple-Reference-Table.pdf) and convert that to a temperature reading. Omega makes some cute USB thermocouple readers/loggers (https://www.dwyeromega.com/en-us/thermocouple-data-logger-with-usb-interface/p/OM-EL-USB-TC-Logger) or you can DIY your own with a sensor chip from DigiKey (https://www.digikey.com/short/j2tdv994)

If you are in a sticky situation with some temperature monitoring of manifolds - or any kind of surface, really - the Omega Engineering SA1 Series Self-Adhesive Polyimide Fast Response Surface Thermocouple (https://www.digikey.com/en/product-highlight/o/omega-engineering/sa1-series-self-adhesive-polyimide-thermocouple) is a great way to attach a reliable and high-quality thermocouple. And, as you might expect, they are in stock right now for immediate shipment from DigiKey! Order today and you will be measuring all sorts of surface temperatures, to your heart's content, by tomorrow afternoon.