Tunnel – Example of using MQTT to activate/deactivate relays of a 3G modem from an Android/IO mobile phone

Scenario details:

• Intended to be able to activate/deactivate relay outputs from an Android or Iphone mobile phone
• The SIM card to be used is very affordable and does not have a public IP address, but a private one of the kind 10.x.x.x

Solution: MTX-Tunnel firmware + MTX-Java-IoT

Configuration example (config.txt file) for the indicated scenario:

Configuration

Observations

GPRS_apn: movistar.es GPRS_login: MOVISTAR GPRS_password: MOVISTAR GPRS_timeout: 0 MTX_model: 199802407 MTX_mode: none MTX_PIN: 0000 MTX_ping: 30 MTX_pingIP: 8.8.8.8 MTX_ATLimited: off FIREWALL_enabled: off TELNET_enabled: on TELNET_login: user TELNET_password: 1234 TELNET_firewall: off TELNET_port: 20023 MQTT_enabled: on MQTT_server: tcp://test.mosquitto.org:1883 MQTT_id: [IMEI] MQTT_attopic1: [IMEI]/AT1 MQTT_qos: 2 MQTT_keepalive: 300 MQTT_persistent: off

GPRS APN provided by GSM operator GPRS Login GPRS Password Modem is permanently connected to GPRS MTX-Terminal modem model used We do not configure gateways PIN if it has one Every 30 minutes PING check IP address for connection checking We do not want limited AT commands All authorized Ips We enable the Telnet of the modem Login for Telnet Password for Telnet They can be connected by telnet from any IP Port for Telnet We enable the MQTT service on the modem We specify the broker IP/DNS, including port Identifier To receive commands Quality of service Keep alive MQTT connection (300 seconds) We do not need persistence

Testing the example:

To test this example, let’s assume that the modem has already loaded the config.txt file and with the inserted SIM. What we are going to configure here is an example for the phone. Suppose it is an Android phone.

• We download an MQTT application of the PlayStore. For example MQTT Dash
• We configure certain details of the application. For example, we created a MTX-TUNNEL device

• Once the MTX-TUNNEL device has been created, we create and configure a button, for example one with the name RELÉ1.
• We configure the name of the relay and the topic that we configure in MQTT_attopic1 (obviously replacing [IMEI] tag with the corresponding imei. We configure the command AT ^ MTXTUNNEL= SETIO, X, 0 in the active button, and in the disabled one AT ^ MTXTUNNEL = SETIO, X, 1 (where we will enter X = 0,1,2,6 depending on the relay to be switched). We can specify a QoS 2.

• Repeating the previous process 4 times (one for each Relay), we can generate an application like the following one