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Month: January 2019

DTMF Automation

DTMF Automation

A large part of phone automation uses DTMF signaling. DTMF stands for Dual Tone Multi Frequency and has been in place since the 1960s. Dialing a phone number before the advent of DTMF involved using a rotor. The spinning dial would generate a number of pulses that the phone company would interpret as a number. The phone company then placed each number in order and after a set number was reached, the phone company would place the call. We still…

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WiFi Scanning Using ESP8266 ESP-01 Module

WiFi Scanning Using ESP8266 ESP-01 Module

In my earlier post I discussed installing the ESPurna firmware on the ESP-01 module, a ESP8266 based IoT device. The firmware provides a Web as well as a telnet UI. In this post we’ll be more focused on the CLI via telnet. More specifically, we’ll be looking at the wifi.scan command issued in a telnet session to determine wireless coverage. The ESP-01 module is well suited for tasks like determining wifi coverage. It is small, can operate on a small…

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ESPurna firmware on Tonbux Power Strip

ESPurna firmware on Tonbux Power Strip

The Tonbux power strip is an IoT device that allows control of each power outlet from a mobile device. These are sold on Amazon for around $30 each. It has a closed firmware that does not allow direct access to the power strip. Instead, a mobile device app must be installed and control is done through the app. From the looks of it, the power strip publishes with MQTT to a cloud based broker. In turn the mobile device app…

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