With wide spread proliferation of low cost wireless technologies such as WiFi, BLE etc and smart phones, there is a need to provide such connectivity to systems across application domains. For example, nowadays wellness industry expects the products such as thread mills to communicate with user phones and provide details of the calories spent so far along with the running pattern.  While it might be possible to incorporate the wireless features in newer designs, there are many cases in which the existing systems need to provide these new features with minimal design changes due to reasons such as re-engineering complexity, costs etc.  This calls for Bluetooth to Serial Adapter that can be interfaced to existing systems over UART and enabling wireless connectivity easily with minimal changes.

In this blog, we will discuss in detail about such an application where by Embien’s eStorm-B1 platform is used as a Bluetooth UART module and performing BLE communication to an Android mobile app.

eStorm-B1 Bluetooth UART Module

Embien recently launched “eStorm-B1”, an automotive ready BLE module as a part of its eStorm offerings. The module supports many peripherals and interfaces such that it can be used as a standalone system or can embed in an existing system to enable BLE communication.

Of the available interfaces such as CAN, SPI, I2C etc, this particular demo uses UART as the choice of communication. For such application, eStorm-B1 will act as a slave module which can receive commands from the host processor via UART and do actions accordingly.

The following block diagram depicts the setup of eStorm-B1 as a UART to BLE bridge,

 Bluetooth to Serial adapter

eStorm-B1 – UART to BLE Bridge Setup

The host processor and the module are connected via TTL UART interface. Interrupt signal from eStorm-B1 can be routed to a digital input of the host processor with interrupt detect functionality such that the host processor is made aware of the connection event occurred between the devices. eStorm-B1 can operate in sleep mode where it consumes ultra low power and the module can be switched between active and sleep mode suitably when data transfer is required.

Bluetooth UART module communication

Based on a simple command set, the host processor can speak to the eStorm-B1 module and in turn communicate with another BLE device such as a smart phone, tablet or an IoT gateway.

The following picture illustrates the serial command sequence between the eStorm-B1 BLE module and host processor via UART,

UART to BLE command sequence

Serial Command Sequence

The following video shows the real time demo of eStorm-B1 UART to BLE bridge application typically applicable in many IoT device developments for enabling BLE communication on existing system.

To show case the same, instead of a host MCU, a PC is used and connected to the eStorm-B1 over an USB to UART bridge. PC is connected to eStorm-B1 module via UART interface using an external commercially available UART to USB converter. Tera term, a terminal emulator is used to transfer the data’s from Laptop to eStorm-B1 module via UART. On the other end, a custom Android application installed in Smartphone is used to receive and transmit the data via BLE. UART to BLE Bridge is suitable for various device designs such as wearable device in healthcare, key finder, tire pressure monitoring system in automotives, asset tracking in industries, etc.

Apart from the above mentioned features, the eStorm-B1 also supports rich peripheral options such as timers/PWM, ADCs, GPIO’s which adds more advantage for standalone system developments in various domain applications such as automotive, industrial, healthcare etc.

About Embien: Embien Technologies is a leading provider of embedded design services for the Semi-conductor, Industrial, Consumer and Health Care segments. Embien has successfully executed many projects for IoT product developments such as healthcare/wellness wearable’s, data acquisitions systems, Gateways, and Data Analytics platforms etc. Embien also offers a set of wearable design collections complete with electronics, firmware and Cloud that can be used to shorten product development costs and time significantly.

Understanding the growth of new technologies and keeping in mind of giving an added value to its existing product eStorm-L1, Embien launched an Android app named “DAQ Suite”. With experience in developing Android app for many segments such as IoT, healthcare, automotive etc we have developed “DAQ Suite” for enhancing user experience in multiple industrial applications such as remote control, remote data acquisition/logging, etc.

This blog is the sequel of the blog “eStorm-L1 as GSM based remote switch” demonstrating the relay control and sensor monitor via an Android app. The following video shows the remote monitoring and control application typically applicable in industrial domain and many other verticals. The demo is setup using the GSM based remote switch and android application controlling the device through SMS command.

For the demo purpose we have connected two LED’s and two switches for demonstrating the relay control and sensor monitor functionality respectively. In the real time application, the LED could actually be a relay with suitable external DC supply for coil excitation and switch could be a sensor/transducer output preferably a digital high/low signal or even a pulse type output. The device stores all the configuration settings corresponding to the user, IO, etc in the EEPROM and hence preserved even on power cycling. Also the device has an option to erase the memory on site and start the user settings from the initial factory default.

The DAQ Suite android app includes the following menu options

  1. Device type selection setting – To select the type of the device need to be monitored or controlled. Available device will be listed in the Device model list box.
  2. User settings – To set the user details such as name, phone number, password, device description, and phone number to be taken for call actions etc.
  3. Relay settings – To set the on duration, ON/OFF delay etc. For multiple relays, the name of the device attached to the relay can be set.
  4. Update settings – To set the update interval for how much time interval the user need to receive the SMS about the current status of the relay and digital input. Many options can be chosen from the list view such as on change, periodic, both and none.
  5. Call actions settings – To set the action to be done on the relay upon calling the device. Either the relay can be switched ON/OFF.

The main screen of the DAQ suite includes the status of the SMS command being sent and time information of the last received/sent SMS. The control switch to toggle the relay and the status LED of the digital inputs is also included in the main screen.

Upon every operation, a SMS will be sent to the device with the predefined command set and the respective status of the digital inputs and relay will be displayed on the main screen based on the acknowledge SMS from the device.

DaqSuite, the user friendly Android App for GSM based remote switch and sensor monitor applications is available in Google Play store. Feel free to try it or contact us for more information.

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.

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.