Power consumption of autonomous IoT devices

Evaluation of the power consumption of an autonomous IoT device

The popular Arduino Uno micro-controller  in combination with GSM/GPRS shields based on the SIM900 chip are quite popular as prototype platform for new developments or autonomous IoT systems. The main challenge to implement a true energy autonomous system is the considerable energy demand of this components if you use them out-of the-box. Data sheets and other supplier information give no or only limited information of the true power requirements.

An evaluation project from CADEMIS determined the energy requirements of a basic setup which might be a useful  indication for the design of related IoT systems.

 

System Setup:

In order to determine the energy consumption a simple system setup was used to determine the current at a 12 Volt battery.

Wiring Schema

A control program  implemented in the Arduino IDE  switches between four different states:

1: GSM board OFF, Onboard LED ON

2: GSM board OFF, Onboard LED OFF

3: GSM board ON, Onboard LED OFF

4: GSM board ON, Onboard LED ON

Between the states a delay of 10 seconds was implemented in order to get a steady reading on the Ampere-meter.

Components:

Arduino Source Code:

The source code for Arduino IDE 1.6.13 to switch between the four states mentioned above:

Source Code Power Consumption Evaluation

Measurement Results:

GSM Shield LED Current / mA Power / mW
OFF ON 54 mA 648 mW
OFF OFF 44 mA 528 mW
ON OFF 68 mA 816 mW
ON ON 80 mA 960 mW

Special remark on switching on the GSM Shield: When switching on the board (between state 2 and 3) the power consumption is between 70 mA and 220 mA for about 5 seconds. As mentioned in several posts in forums causes every switching operation a significant peak in current and power.

Summary:

It is strongly recommended to switch off unused loads in order to reduce the power consumption by up almost 50% for a simple setup like this. This can double the operation-time between battery reloading or reduce the solar power requirements and costs.

References:

  • Thanks to the girls and guys from Geeetech for publishing the basic information on how to control the SIM900 board:

http://www.geeetech.com/wiki/index.php/Arduino_GPRS_Shield

Cademis Weather Monitor

CWM System OverviewCademis Weather Monitor is an environmental monitoring system which allows global access to sensor information from in and around your home.

Based on established communicaiton standards and with our Open Access policy it will enable everyone to build a solution step by step.

Follow these pages to get up and running  or let us know if you need a specific solution (special sensors, special data management, smart data analys, actuator interface) and we will try to help.

Galileo 7 + 8 in Space

Two additional Galileo satellites are now in space  and also additional  projects have started to prove the core technology. By 2019 there will be 30 satellites in space and the system ready for civil applications.

According to a report on  02elf.net two additional research activities (“automotive GATE” and “train Gate”) recently started. Goal of these projects is the development the required technology for industry applications in the area of autonoumous driving or cars, trucks and trains.

With the upcoming Internet of Things (IoT) this devleopment is essential to have a new technology available, which can succeed the older GPS. Major advantage of Galileo is the better coverage and the stronger signal, which will allow new applications in home-, industry- and laboratory-automation, due to lower energy consumption and higher precession.

 

Galileo
ESA Galileo Satellite in Space; Copyright: ESA-P. Carril

Clarks uses iPads to measure your feet and to collect biometric data

Its all about big data – Clarks places iPad based devices in shoe shops to support customers and improve the shopping experience. But as a nice side effect it also collects biometric data about your feet and process this data at its headquarters in order to get  information on regional trends.

Have a look at the video to get an impression about the combination of old and new technologies in today’s shoe industry.

Vienna Citizen Sensor Projekt

Open data initiatives in Vienna, Amsterdam and Barcelona try to develop technologies to enable citizens to collect and share enviromental data.

Main challenges seems to be the development of  an inexpensive hardware platform with acurate sensor-data and stable communication technology.

More at futurezone.at

Bürger-Sensoren: ‘Smart City auf der Grätzel-Ebene’ – futurezone.at.