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.


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.


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.


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



Here you find the latest news on the CODESYS development system from 3S-Smart Software Solutions GmbH:

CODESYS for Rasbery PI

Now you can even run you PLC program on the popular Rasbery PI platform. Available from the CODESYS website you can download the required software for EUR 50. A limited free demo version works for two hours.


Have a look and enjoy the brave new PLC world. Looking forward to hear from your adventures and experiments with this new tool for (serious) Makers.


European Robotics Forum, 21 – 23 March 2016, Ljubljana

ERF 2016The next edition of the European Robotics Forum (ERF2016) will take place in Ljubljana, Slovenia, from the 21st to the 23rd of March 2016.

Invited are all engineers, researchers, managers and entrepreneurs active in the field of robotics.

Organized by  EUROBOTICS and sponsored by European Robotics players like Schunk, ABB and KUKA it will present the latest research and applications of the European robotics community.

Ljubljana Castle

Looking forward to see you Ljubljana!


Arduino Yún Essentials

The Arduino Yún is the frist true IoT board from Arduino which gives you a real-time controller combined with a Linux environment with almost unlimited connection possibilities (Ethernet, WiFi, USB)

It is the best tool to monitor and control your devices, and here you find a few instructions to get you up and running.

Arduinio Yun
Arduinio Yun

Upgrade to latest Linux (optional)

If you are not sure if you have the latest Linux version on your Yun you will need to upgrade. To upgrade or reinstall the OpenWrt-Yun image on your Yún, you’ll need to download the zip file from the download page. Once you’ve unpacked the file, move the binary image file to the root folder of a microSD card and insert the card into the Yún.

The recommended way is to upgrade through the Web Panel. Find the step-by-step instruction here: https://www.arduino.cc/en/Tutorial/YunSysupgrade

Next step is to connect the Arduino Yun to your wireless network:

Connect to your WIFI NEtwork (WLAN)

After WLAN reset and when you first power on the Yún, it will create a WiFi network called ArduinoYun-XXXXXXXXXXXX. Connect your computer to this network!

Once you have obtained an IP address, open a web browser, and enter http://arduino.local or in the address bar. After a few moments, a web page will appear asking for a password. Enter “arduino” and click the Log In button.


You will find a page with some diagnostic information about the current network connections. The first is your WiFi interface, the second is your ethernet connection. Press the Configuration button to proceed.

On the new page, you will configure your Yún, giving it a unique name and identifying what network you want to connect to.

In the Yún NAME field, give your Arduino a unique name. This is important if you plan to use more than one Yun on your network in the future. So if you name it yun123 you will need to connect to http://yun123.local the next time to want to configure the wifi settings.

Choose a password of 8 or more characters for your Arduino. If you leave this field blank, the system retains the default password of arduino

If you wish, you can set the timezone and country. It is recommended to set these options as it may help connecting to local WiFi networks. Setting the local timezone also selects the country’s regulatory domain.

Enter the name of the WiFi network you wish to connect to.

Select the security type, and enter the password.

When you press the Configure & Restart button, the Arduino will reset itself and join the specified network. The Arduino network will shut down after a few moments.

You can now join the network you assigned to the Yún.


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.


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