Hot or not? Now you will know to 0.1 degree precision!
What is a temperature sensor?
An analog temperature sensor is pretty easy to explain, its a chip that tells you what the ambient temperature is!
These sensors use a solid-state technique to determine the temperature. That is to say, they dont use mercury (like old thermometers), bimetalic strips (like in some home thermometers or stoves), nor do they use thermistors (temperature sensitive resistors). Instead, they use the fact as temperature increases, the votage across a diode increases at a known rate. (Technically, this is actually the voltage drop between the base and emitter – the Vbe – of a transistor. By precisely amplifying the voltage change, it is easy to genereate an analog signal that is directly proportional to temperature. There have been some improvements on the technique but, essentially that is how temperature is measured.
Because these sensors have no moving parts, they are precise, never wear out, don’t need calibration, work under many environmental conditions, and are consistant between sensors and readings. Moreover they are very inexpensive and quite easy to use…
Some basic stats
These stats are for the temperature in the Adafruit shop, the Analog Devices TMP36 (-40 to 150C). Its very similar to the LM35/TMP35 (celsius output) and LM34/TMP34 (farenheit output). The reason we went with the ’36 instead of the ’35 or ’34 is that this sensor has a very wide range and doensn’t require a negative voltage to read sub-zero temperatures. Otherwise, the functionality is basically the same.
- Size: TO-92 package (about 0.2″ x 0.2″ x 0.2″) with three leads
- Price: $2.00 at the Adafruit shop
- Temperature range: -40°C to 150°C / -40°F to 302°F
- Output range: 0.1V (-40°C) to 2.0V (150°C) but accuracy decreases after 125°C
- Power supply: 2.7V to 5.5V only, 0.05 mA current draw
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — HOW ANKER IS BEATING APPLE AND SAMSUNG AT THEIR OWN ACCESSORY GAME
Wearables — Spooky liquids
Electronics — The deets on Electret Microphones
Biohacking — Mind-Controlled Spermatozoa
Sorry, the comment form is closed at this time.