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Submit your low power ideas (max. 2 ideas per user) in the comments below by September 26th, 2015.  Our internal jury will select up to 30 submissions, and the winners will receive a free EFM32 STK ($67 USD). Compare different EFM32 STK options here.


View Judging & Winner Announcement Information Here  



By entering the contest, you acknowledge that you have read and agree to the Community Contest Terms and Conditions 

  • Projects
  • 32-bit MCUs
  • Adaptive, Gridless Yard Solar Holiday Lighting Controller


    I want to use the EFM32's Low Power Features to sequence holiday light decorations in our front yards, off the grid. With the increased success in solar lighting in recent years, it makes a lot more sense to set up yard decorations without connecting to a 120V or 220V electrical outlet. This completely removes the risk of electrocution from stringing electrical wire through the snow. Additionally, this is cheaper, more energy-efficient, and a lot easier to set up. However, it means we have to find other means to power the lighting, such as batteries or solar.


    The EFM32's Low Power features will be used to reduce power consumption not just in the CPU itself, but—more importantly—in the lighting. When lighting displays are sequenced using a microcontroller, they not only look better, but they also consume less power. Power consumption can be monitored and rationed using a variety of methods through the EFM32 controller:


    1. Go into Shutoff Mode when ambient light exceeds a threshold for a prolonged period. It is assumed that this is because the sun is up. Thus the display should shut off.

    2. Go into Sleep Mode and turn off the lighting when ambient light exceeds a certain threshold for a short time. This could come from a car's headlights, or other man-made light source outshining the display.

    3. Adapt light sequences based on how much battery is left. Some sequences consume less power than others.

    4. Ration out power to last for a targeted amount of time. For example, we may only want yard ornamentation lit from 18:00pm to 23:59pm at night, because no one is even out on the roads after midnight.

    5. Adapt solar lighting's power consumption based on how much sunlight the solar cells got that day. Some days are sunnier than others. Some places—such as Oslo—get very little sunlight during Christmas time, but during the summer it is the opposite: it is almost never dark.

    6. Initiate more lively, but more power-consuming sequences when a motion or IR sensor senses movement—since it is more likely that passersby are actually viewing the display.

    7. Automatically notify the owner of the yard display that power is running low: the minimal lighting sequence will convey that.


    This application takes advantage of the following Low Power features of the EFM32:


    • LESENSE. The CPU needs to monitor ambient light, motion sensors, and the 24-hour clock during the majority of the time while it is asleep.

    • Fast wake-up time. The lighting display turns quickly on-and-off when motion is detected, or when other lighting (such as auto headlights) temporarily outshines the display.

    • Peripheral Reflex System. Some simple lighting operation can actually occur while the CPU is asleep, during periods when very little power is available.

    • Multi-level sleep modes.

    • The Voltage Comparator. Required to monitor available battery power.


    Do note that, in spite of the Low Power Contest falling right around Christmas, this application by no means is limited only to Christmas lighting. Indeed, the hope is to develop a software library in Simplicity Studio so that others can adapt their own wireless displays, with their own sequencing, to the EFM32.

  • Considering the very low power operation that EFM32 makes possible, I came up with an idea for using it on a solar energy converter. The concept is to make it the controller of a buck-boost converter, allowing for energy harvesting from low voltage solar cells.

    The input voltage from a string of solar cells would be something between 1 volt and 6 vols, and the output voltage would be 5 volts fixed. Using all the processing power of EFM32 makes it possible to achieve a fast control loop, while keeping the system power consumption very low. It is important to keep losses low (thus an efficient and fast control) to drive the system efficience up.

    The application for this energy converter ranges from remote locations weather stations to sensor nodes and also security and monitoring.

  • i want EFM32 STK low-power device to transfer energy with the help of iot.

    Transfer energy to another continent.

    [we could make electricity from even wifi signals].Why could we share those energy

    Nari wrote:

    Submit your low power ideas (max. 2 ideas per user) in the comments below by September 26th, 2015.  Our internal jury will select up to 30 submissions, and the winners will receive a free EFM32 STK ($67 USD). Compare different EFM32 STK options here.


    View Judging & Winner Announcement Information Here  



    By entering the contest, you acknowledge that you have read and agree to the Community Contest Terms and Conditions 


  • My idea is to develop an ambient environment sensor that measures lighting levels,
    proximity, temperature and humidity and reports the current status over a NRF24L01
    based 2.4GHz wireless network to a base station. The sensors are battery powered
    and can be deployed both inside and outside of the house.


    The information gathered by the sensors can be used to monitor and adjust for
    environmental conditions (by monitoring the light and temperature levels in a
    garden for example) and provide triggers to automate other processes (turning
    off the lights in a room if it has been unoccupied for a certain amount of


    The sensors will be battery powered and my goal is to be able to power a sensor
    from a single 2000mAh AA battery for 6 months. This requires the average current
    consumption of the sensor to be less than 150uA over it's operating period. To
    achieve this goal will require very careful power management.


    The design uses a number of Silicon Labs products including:


    • EFM32 Cortex-M0+ Microcontroller
    • SI7054 Temperature/Humidity sensor
    • SI1141 Ambient light and Proximity sensor

    All of these products can operate with very low current draws which will aid in

    meeting the target. In addition the LESENSE features of the EFM32 will allow
    for additional sensor inputs (such as soil moisture) to be added in the future
    that can be activated and read while the CPU remains in low power mode.


  • My Idea is to develop an EFM32 + BLE based name card, with E-Ink display.


    This name card will be carried out by a people, put it into your pocket and show them to customers, and the BLE will start to advtising, so your customer can use smart phone to receive these infomation, include:


    Company Profile


    Contact People

    Telephone Number




    As the name card will have a display, so it can can also be directly display your info on it, like name, contact info, title. And the name card can be weared in your clothes, so when you go into a bar, if the server wear the name card, it can let customer know the name, and let customer know the QR code, which is good for biz development.


    As the phone can connect to the name card, the phone capble of changing the display image any time any where, so the name card also can become a note for transfer infomation between family members, collegues, etc.


    EFM32 low power features and E-Ink display reference design is right fit for this application, also the GigaBlue BLE module can accelerating the time from idea to prototype, and finally to market.


    How it can be achieved:


    EFM32 + Giga BLE Module + Si114x Light senor



  • design.png


    A Smart Farm

    My idea is to develop a smart farm system that uses EFM32 with battery powered. It measures temperature, humidity and soil moisture. The measurement results will be sent included battery energy level to a base station through XBee IEEE 802.15.4 if the threshold values are achieved, such as high temperature, low humidity or low battery energy. A decision to send a report to a base station uses Fuzzy approach. Some rule set are defined to build Fuzzy control system for a smart farm.


    By utilizing LESENSE features on EFM32, a smart farm system works with efficient energy consumption. After acquired data from sensor, a smart farm system analyzes the data using a Fuzzy controller. If no decision to send data, EFM32 will sleep. Otherwise, it sends the data to a base station.

    The following is required hardware modules:
    * EFM32
    * Two XBee IEEE 802.15.4 modules
    * Temperature and humidity sensor module
    * Soil moisture sensor module




    This project is related to wearable electronics.


    A series of LEDs are sewn to a vest and then laminated for waterproofing. It is intended to be worn by motorcyclists, traffic enforcers, police officers, construction workers, or anybody who needs to be visible in challenging light conditions for safety purposes. Examples are working during the night or in a foggy environment. It will be powered via a Lithium-polymer battery so it's rechargeable and lightweight. It will employ accelerometer, gyro, and magnetometer (all MEMS) to detect body position at any point in time. The vest also has an embedded low-energy Bluetooth (BLE) that will enable it to connect to the smartphone carried by the person wearing the vest so when an impact condition is detected (by interpolating data from the IMU sensors), it will automatically send a text message or initiate a call to an emergency hotline number (or to any number set by the user), indicating the location by giving the exact GPS coordinates from the smartphone's GPS.


    I believe that the EFM32 Cortex-M0+ Microcontroller is the most suitable controller for this project. It can execute processor intensive algorithms at far less the energy than executing the same algorithm on an 8-bit or 16-bit micro. This is very important as I will be running some sensor fusion algorithm to continuously monitor and interpret the data from the IMU sensor. Another feature that I like with the EFM32 is that it does offer different levels of sleep modes, which will allow me to optimize energy consumption on the little Li-Po batteries that I have to embed in the vest. I can use the LESENSE for monitoring the ambient light to tell when the vest should be "active" so the LEDs and the system is automatically turned on when a particular ambient light level is reached. In this concept system, the major energy consumers are the LEDs. The intelligence of the EFM32 microcontroller would allow me to save energy on other aspects of the system. The advantages offered by Simplicity Studio for energy profiling would be of great help in evaluating the energy consumption of the micro as I run the algorithms while monitoring a multitude of sensors and controlling external IC's.


    To wrap up, this project is intended to involve the following as major components:

    1. EFM32 Cortex-M0+ Microcontroller

    2. 9-DOF sensor

    3. BLE module

    4. Ambient Light Sensor

    5. Li-Po Batteries

    6. LEDs

    7. Temperature and Pulse Oxymetry sensors (future enhancement)


    Thank you.

  • I'd use a SIlabs EFM32 to power a smart navigation system for cycles and motorcycles. The system would use EM3 or Stop mode the majority of the time, taking interrupts from an accelerometer and some sort of crash sensor.


    The device would feature the following functionality

    1. Implement an anti theft feature for when you park your bike. Stop mode would be perfect for something like this, connected to a bluetooth 4 module.

    2. Implement crash detection and automatically inform first responders in the area.

    3. During a ride, it would use sleep and use bluetooth to communicate with a users phone as well as briefly turning indicator leds on and off for navigation.


    This would use a lot of LESENSE optimization as its entire purpose is to collect information from various sensors and pass them onto a phone and vice versa.


    Thus, because of the EFM32 it will be extremely low power

  • Industrial Automation Process Data Display


    In many automated industrial facilities process information is transmitted to a central location. This information is available in a local HMI (Human Machine Interface) that usually is located several hundred feet from instrumentation.

    When maintenance personnel work on some of the instrumentation, they typically have to move back and forth from the location they are working at and the local HMI to check process values or check values via radio with the operators. This common design is to reduce costs of having local indicators on the instrumentation and to require cabling power to some of these locations that may be hazardous.


    The low power features of the EFM32 allows creating a very small all included (even power) device that can be installed really close to instrumentation to display process data right on the point where it is produced.


    A very small board, based on an EFM32, completely encased in epoxy, with its own power enough to last several years and only having a pair or RS485 terminals can be glued in top of any device, for example a pump. When a user comes near the pump, just touching the device will make it wakeup, communicate with the PLC or device that contains the data and show it in the screen.


    So, the proposed device is a completely encapsulated device with a LCD screen and battery with a few exposed wires. Wires would allow communicating with instrumentation devices using: Modbus over RS485, 4..20mA current loop sensor with HART protocol.


    The features that make the EFM32 important for this application are:

                LCD Screen handling capability

                LESENSE based low power capacitive sensing for user interface

                UART for Modbus Communication over RS485


    Because of the large integration of function in the EFM32 this project can be made at a very competitive cost that will make it very attractive in industrial installations.


  • Interactive Music Toy


    This proposal involves a series of conductive stickers that can be glued to the walls. Each sticker is connected to a small EFM32 based board with a small non-user replaceable battery. When any of the conductive stickers is touched, the capacitive sensor of the EFM32 detects the touch and sends a code via IR (Infrared).


    Another EFM32 based device that contains an IR sensor is able to detect the touches and makes a sound in response to the sticker touch. The system is fully configurable, including the sounds played and or even the IR codes sent.


    The full system could be configured to convert entire rooms into musical instruments or remote controls of devices like TVs. For example a big button on a wall can be linked to a power on command over IR or some logos can be configured to change channels to a specific channel.


    Furthermore more sensors could be added to implement things like turning on lights.