Powering an Arduino Pro Mini logger for one year on a coin cell
The Cave Pearl Project has continued development of a ‘lite’ version of a data logger with the lowest possible cost and assembly time. The latest version is now ready for release with data download & control managed through the Arduino IDE’s serial monitor window.
With just three core components as our starting point, the only hardware option was to remove the SD card. Groundwork for this change was already in place with our use of an EEprom to buffer data so that high-drain SD saves only occurred once per day. Getting rid of power hungry cards also opened up the possibility of running the entire unit from the coin cell on the RTC.
An 8Mhz Pro Mini continues as the heart of our loggers because the 328p is still the easiest low-power option for projects that aren’t computationally demanding. These clone boards usually sleep below 1µA with the BOD turned off, but it’s worth noting there are some with fake Atmel chips that won’t go below 150µA. Cheaper boards usually ship with ceramic regulator caps but that just makes them more resilient if you accidentally connect power the wrong way.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
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