Using a battery or solar energy to supply a development board with power can sometimes be tricky. TPL5111 Low Power Timer Breakout Board offers a solution for that. With the help of it, you'll be able to turn any electronic device into a low-power device.
It will take care of enabling & disabling your electronics using a built-in timer that can vary from once every 100 ms up to once every two hours. Basically, the TPL will set an enable pin high periodically. You can adjust the period with a potentiometer or resistor, and the TPL will turn on your project's power. It will then wait until a signal is received from the project to tell the TPL that it can safely disable the project by setting the enable pin low. If the TPL does not receive a signal by the set time-out, it will reset the device just like a watchdog timer.
It is quite easy to use: First, set your desired delay but adjusting the onboard trimmer potentiometer: all the way to the left is once-per-100ms and all the way to the right is once-every-2-hours. Then, connect VDD up to your 3-5 V project power supply, and then your project's enable pin to the Enable pin. Finally, select a signal pin from your project to the Done pin. In your project's code or design, just make sure that it sets the Done pin high once it is completed with its task.
While the TPL5111 is running (but the remainder of the project is de-powered) the current draw is about 20 µA.
If you want to turn the device on by hand, you can also activate the TPL by pressing the onboard tactile switch.
Comes as a fully assembled breakout board with a TPL5111 chip, all components on-board, and some header. A little light soldering is required to put it together for breadboard use.