Monthly Archives: October 2013

Instructions from the AVR power library for ATmega328P

The library <avr/power.h> makes it easy to shut down all unneeded hardware of an ATmega controller.

The documentation of this library shows all available instructions and also on which controllers they are working. As I didn’t find this very readable I copied the table and deleted everything that doesn’t apply to the ATmega328P. Continue reading

Arduino powered by a capacitor – reducing consumption

atmega_capacitors_pv_2The first test showed that there is a lot of power reduction potential in having the controller sleep when it doesn’t have to do something. Now it’s time to look in detail to the possibilities of saving power both while the controller is running and during sleep. With simple test sketches measurements are done with different configurations to see the effects and to find out how low power consumption can be. Continue reading

ArduinoISP: reading and writing fuses on ATmega328P

An arduino board like the Uno can be a programmer for a standalone ATmega chip. For the ATmega328P that is used in the Uno there is a tutorial on the arduino homepage. This lets you burn the bootloader into the chip without the need for other hardware. This post shows how to use the same configuration for reading and writing the fuses on the chip. Continue reading

Arduino powered by a capacitor – first tests

atmega_capacitors_pv_1This is the second post about powering an arduino from a capacitor. The basic setup is described in the introduction. It’s an ATmega328P in a standalone setup with use of the internal clock source. The power comes from the two capacitors on the picture. The microcontroller measures it’s own supply voltage repeatedly in intervals and writes data to the onboard EEPROM. After starting the measurement the power supply is plugged out and the ATmega runs off of the capacitors until the voltage is too low.

In this post I will describe how long the setup can run with different power-reducing techniques. Continue reading

Arduino powered by a capacitor – the start

atmega_capacitors_pvLet’s take a capacitor as the power source for an arduino. But what sense does that make? This is totally nonsense you might say. A capacitor can’t store enough energy to run a microcontroller for a considerable time. Take a rechargeable battery to get it running. You’re right (at first sight).

But let’s have a closer look at this. The idea behind is: How long can a microcontroller like e. g. the ATmega328 run off of a capacitor when power consumption is reduced to the limit? When we get reasonable results we could make a Minimal Solar Arduino with a capacitor to store the energy. This is the idea behind this project: Building a solar powered arduino system with minimal power consumption and a minimum of components. The project is inspired by these great articles: Power saving techniques for microprocessors from Nick Gammon and Operating an Arduino for a Year from Batteries from Alan Mitchell. Thank you both for your work! Continue reading