Hello,
I’m looking for some assistance on a few questions regarding temperature/humidity sensors.
I’m working on a college business project that requires an electronic temperature/humidity sensor that can recognize quick changes in either the temperatures or humidity.
After browsing the Robot Shop electronic sensors online, can anyone recommend a product(s) that
a) can be powered by a small battery (watch cell or LR44 alkaline cell),
b) can be connected up to 2 sensors to detect the temperature/humidity change, and
c) able to detect and send a signal/alarm when temperature/humidity increases by 3-4 degree’s F within a 10-30 second time period
Thank you and I look forward to your response!
-Eddie
Here are answers to your comments/questions:
We assume you need the project to read both and react to changes in either (or both)? We also assume “quick” is defined as “10-30 second time period”.
A LR44 would have a nominal voltage of ~1.5 V DC (and an end point of ~1.0 V DC). Most electronics will work at around 3.3 V DC or 5.0 V DC. Some will typically go as low as 1.8 V DC in hobbyist grade hardware. Since the cell will not provide this voltage by itself (and voltage will drop over time), you will most likely need a “step-up” voltage regulator (take a voltage and makes it higher and stable). An example of one for 3.3 V DC would be the RB-Pol-213 (roughly 85% efficient) and for 5.0 V DC, the RB-Pol-216 (roughly 80-90% efficient, requires 2.5 V DC input). the choice of output from your regulator will depend on what electronics you will be using. Going for 3.3 V DC-based electronics would most likely make your power circuit easier.
Most likely any standard microcontroller board will do for this. Most sensors either have a I2C, SPI, UART or analog output/interface and therefore most if not all microcontrollers we offer should be able to use them. That being said, an important point here will be to use a microcontroller that uses very little current (since using LR44) and also has sleep modes (most modern microcontrollers has some, but some are far better than others at it). Some of the very low power TI MSP430 chips can use as little current as ~3.5 mA @ 16 MHz!
You did not specify what type of alarm you are looking for. Is this some form of electrical output to another circuit (digital, analog, etc.)? A LED or buzzer? Some wireless communication? Something else or a combination of these? This will also have an impact on your microcontroller choice for your project.
As for the temperature/humidity sensor(s), you will need to have a look again here and check datasheets to find one that fits your requirements, such as how fast it react to environment changes (10-30 seconds ?). Also, you will want sensors that use a little power as possible and maybe even have a form of sleep mode that you can use to reduce current consumption.
We hope this helps you get started.
Sincerely,
