Recently I have been doing some research to discover how to design and develop my own battery powered customised wireless sensors to monitor and report on various physical quantities such as temperature, smoke, and water level around my home. One of my key design requirements is long lasting battery power to minimise the regular cost and inconvenience of replacing batteries. Another design requirement is to use a small form factor to keep the hardware compact so I can fit it into small spaces. In thinking about the need to reduce power consumption, one idea is to utilise controlled power cycling to only power up the wireless sensors for short regular periods to capture, store, and transmit the data readings or recordings. By choosing a small power up duty cycle, the sensor and associated electronics would only come on for a brief stint to do its job and then go to sleep and wait for the next cycle. This approach would extend the useful battery life compared to using continuous power to the sensor and electronics. Micro-controllers can be used to drive the power switching electronics to cycle power to devices.

As a starting point, the two guiding requirements basically meant that I would need to investigate and discover which family of micro-controllers could offer such features.  I am a big fan of the whole Arduino movement and it made sense to firstly investigate the ATMEL^® AVR family of micro-controllers. There are about 34 different micro-controllers in the ATtiny family. Within a few minutes of doing a Google search I found an excellent Wikipedia comparison chart for the ATtiny family of micro-controllers. Below I have just extracted data for the micro-controllers that have 8 or less pins and packaging that my fat fingers can handle. The data was sourced from Paul Rako who compiled selection data for all tinyAVR parts in 2014. It is an excellent reference!

I was looking at solving the problem of how to shrink my Arduino projects and how to operate them at lower power consumption so I could use batteries that would last for months if not years. While there are may parameters you can consider in choosing an appropriate micro-controller, the ATtiny13A highlight in yellow in the table above has one unique feature compared to the other members of its family. It has picoPower capability! All ATMEL picoPower devices are designed from the ground up for low power consumption utilising Atmel’s proprietary low leakage processes and libraries to provide low power consumption in active and sleep modes.

Low powered Internet of Things (IoT) sensor nodes or devices can be driven by ATtiny13A 8-bit AVR^® Microcontroller with 1K Bytes In-System Programmable Flash

ATtiny13A data specifications 176 pages 4.3Mb PDF (http://www.atmel.com/images/doc8126.pdf)