Datasheet

9 | Page

The IRDA can also be used if the GertDuino is used stand-alone to control the connected logic

using a remote control.

Note that 95% of all TV/Video/CD remote controls use the 38KHz infra-red signal, but the

coding varies greatly from type to type.

4.6 Battery Drain

If a battery is present and the power of the Raspberry-Pi is switched of the Atmega-48 will still

remain powered by the Battery. It will also keep running. Unless the battery is removed or the

Atmega-48 is programmed to go into a special ultra-low-power condition, the battery will be

drained in a short time.

Even if you think the device is in ultra-low-power mode it can still consume power if it has to

drive outputs high.

Measurements have also show that if a UART connection exists between the Atmega-48 to the

Raspberry-Pi (even if it is not used) that increases the lower power current from 1µA to about

100µA.

To measure the current consumption you have to use a 3V supply and connect it to the battery

holder but between the supply and the battery holder you have to place a current (Ampere)

meter. Optionally you can connect a scope on one of the I/O pins of the Atmege48 to see if the

program is running. You should NOT connect anything to one of the output which loads an I/O

pin as that will cause extra current consumption.

This is a block diagram of the setup:

Atmega48pa

Gertduino

GND

And this is how it looks in real life:

The meter shows a current consumption of 1.3µAmp. (The meter is shown enlarged in the lower

left hand corner of the picture) .