eStorm-L1 is a commercial off the shelf product from Embien. Loaded with many features, it is mainly crafted to support quick realization of customer requirements. eStorm-L1 has been currently deployed across industries for various functional applications.

This blog captures one of the most popular applications of eStorm-L1 as a GSM Remote Control Switch. Being based on our proven and reliable platform, the GSM remote switch brings to the industry a low cost solution and help reducing the man power. With just a SMS command to the device, multiple loads can be switched on and off. It also supports acquiring the current status of analog /digital sensors attached to it. Apart from industry applications, this remote switch can also be used for home automation purposes.

eStorm L1 – Device Information

eStorm-L1 based GSM remote control switch is a remote monitor and control device equipped with GSM connectivity and external digital IO interfaces.

Powerful MCU: The device is powered by industrial grade ARM Cortex M0+ micro-controller. It holds rich IO interface supporting multiple digital inputs and relay control outputs. The core can run at 48 MHz that is quite powerful for remote control and monitor application.

Digital Inputs and outputs: The device supports up to 4 digital inputs mainly to acquire the data from the sensor/transducers. There are option for up to 8 digital outputs in relay mode and 4 digital outputs in digital switch mode. Digital switch mode supports direct control of the load connected across the terminals whereas the relay mode supports the external relay control which controls the load connected it.

GSM Communication: The device includes dual band GSM modem with on board antenna and SIM card holder. The device supports standard 6-pin SIM card with 1.8V and 3V operating voltage.

Storage: EEPROM available in the device supports storing configurations and user account details such as user name, phone number, password etc.

Field upgrade: USB device and configuration switch is provided for field upgrade. Connecting to the PC/Laptop with the provided application and firmware will be sufficient to do the upgrade task.

Enclosure: The device is carefully designed and enclosed inside an ABC plastic enclosure to sustain under rugged industrial environment. It can be mounted on the wall through the protruded flanges in the sides of the enclosure lid.

Remote Control Switch – Operation

Device requires a valid SIM card to be inserted in the SIM card holder. User should carefully connect the load / sensors to the respective terminals. Load connected to eStorm-L1 can be controlled remotely by just sending a SMS command or a missed call for relay control. There are options for configuring one admin and up to 10 users. Only the admin has rights to add, delete the user accounts etc. Password and phone number should be valid to control the device.

Configuring the device is very simple. Just a missed call to the device will provide the administrator, a user name and password through SMS. This user name and password should be added in all the commands for valid operation and the same can be changed by the admin through SMS command. Following are the command groups and available commands that are supported by the device for remote switch application.

  1. Relay commands
    1. Group switch on/off relays
    2. Individual switch on/off relays
    3. Setting ON/OFF delay
    4. Setting ON duration
    5. Setting Relay status update option/period
    6. Setting missed call control action
  2. Inputs commands
    1. Group of inputs enable/disable
    2. Particular input enable/disable
    3. Setting ON/OFF de-bounce
    4. Setting input status update type and period
  3. Admin commands
    1. Add user
    2. Delete user
    3. Change password
    4. Change user phone number
    5. Getting user list
  4. Query commands
    1. Query device information
    2. Current relay and inputs settings
    3. Current status of inputs and relays
    4. Device network signal strength
  5. Help commands
    1. Missed call action command format
    2. Relay command format
    3. Input command format
    4. Admin command format
    5. Query command format

For all the above command types there are shortcut commands which supports easy and quick control actions for the user handling the device. Except the admin commands all the users have rights to use the commands providing a better hierarchy in control.

Following figure depicts example SMS command sent to the device and response received from the device respectively.

Example 1: Consider all relays are in off state. Issuing a command with user name and password to switch on relays connected to digital outputs 1, 3, 5, 7 at a time. The response confirmation message from the device will describe the list of relays in ON state i.e. 1, 3, 5, and 7 and the list of relays in OFF state i.e. 2, 4, 6, and 8.

Relay On command

GSM Relay On command

Example 2: Consider the relays 1, 4, 5, 8, inputs 1, 4 is ON and relay 2, 3, 6, 7, inputs 2, 3 is OFF. To get relay and input status information’s, sending query command to the device. The relay and inputs status will be sent by the device as shown in the figure upon the SMS command reception.

Status Query Command

GSM Switch Query Command

Apart of this GSM control, Embien provides a free Android App in the Google Play Store where the relays and sensors can be monitored/controlled graphically with touch of a button.

Applications of the GSM Controller

GSM based remote switch applications are generally numerous and with Embien’s device designed specifically for operating in -40 to 80 degrees, the net get even wider. Some of them include the remote control of industrial lighting, exhaust fans, engine/machine pre-heaters, cabin heaters, water well pumps, single phase/ 3-phase irrigation systems, power cycle and reboot of remote servers, routers and computers, HVAC – heating and air conditioning in holiday homes, aviation engine heaters, pumping stations, etc.


About Embien: Primary focus of Embien technologies lies in the Industrial Automation segment. We have a rich experience in working on industrial automation and control systems with customers across geographies to enable their factories and assembly lines run efficiently. Our team have developed protocol stacks for various industrial protocols and enabled them in customer devices. We have created various Human Machine Interfaces (HMI) systems to make easier the interface with the machine. Our Machine to Machine (M2M) service offering includes developing system capable of remote monitoring and controlling of machines, PLC’s, etc.