By Yuuki Okamiya
Date: May 14, 2013
The following is the GR-KURUMI Consumption Current Report. Please keep in mind that these measurements were taken using an older library.
Personally, assuming use of a single battery, KURUMI consumes more consumption current than I expected. Using a delay in STOP mode to suppress the current to some extent and running the application in NORMAL mode gives only 100 hours of operations with one alkaline battery.
To have a long operating time, set the booster IC to OFF (JP8), and operate KURUMI by supplying power from two batteries (around 3.0～3.2V) through Vcc.
Keep in mind that when operating with a delay (ms) using milliseconds as the argument, current consumption will be slightly larger when 0xFFFFFFFF (Interrupt wait period) is specified, because GR-KURUMI wakes/sleeps in 1ms intervals. Even when using a program that ensures longer sleep periods, with 0xFFF as the maximum compare match value and 100ms resolution, the current can be further suppressed, but the improvement is small and will only serve to complicate the implementation.
*** CONDITIONS ***
GR-KURUMI V1, RLduino78 library E0.93, GNU RL78 V13.01
Power LED is set to OFF (cut P1) and the pull-down resistor of the regulator output level remains as is (constant flow of approx. 5uA). Note that the regulator consumes 19uA even with 0 input.
Measured in loop
Measured in delay(ms)
Measured in delay(0xFFFFFFFF)
Measured in analogRead(pin)
Supplement concerning measurements:
The photos below show the basic environment and set up used for measurements.
The clip is attached directly on KURUMI for measuring. We realize that measurement results can greatly differ with contact resistance based on the uA order, but the setup in the photos seemed to provide the most stable conditions.
(No photo in the original post)