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…

Read More Read More

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…

Read More Read More

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…

Read More Read More

Monitoring Wireless Sensors

Monitoring Wireless Sensors

In this post we’ll cover how to monitor inexpensive wireless security sensors. There are two types of wireless sensors that we’ll be working with, door reed switches and passive infra red motion detectors. Each of these sensors transmit a broadcast radio message on the 433Mhz frequency. We’ll be expanding on earlier work with RTL_433. This post will cover how to identify a specific sensor and take appropriate action as needed, all that with a single bash script, let’s begin. The…

Read More Read More

Weather Monitoring with SDR and Cacti

Weather Monitoring with SDR and Cacti

This post will cover how to monitor a Acurite temperature and humidity sensor with RTL_433 and a SDR dongle. Values from the sensor will be collected using a shell script and the results will be graphed in Cacti. Let’s begin. The Acurite sensor used is model number 06002M and it is the indoor outdoor sensor. It can be found on Amazon and currently lists for $13 each, http://a.co/d/fPybnET. It is powered by 2 AA batteries. The manufacturer suggests using Lithium…

Read More Read More

RTL_433 SDR IoT Sniffer

RTL_433 SDR IoT Sniffer

In this post I’ll be covering how to use SDR on Linux to capture data from wireless sensors using Benjamin Larrson’s RTL_433.  I’ll start by covering the required install steps followed by some rudimentary examples.  First you will need some kind of USB SDR hardware, this example we will be using the NooElec Nano. Here are the steps to install the RTL_433 software.  Open a terminal window and enter in the following commands. sudo apt-get install libtool libusb-1.0.0-dev librtlsdr-dev rtl-sdr…

Read More Read More

Capturing NOAA Satellite Images with SDR

Capturing NOAA Satellite Images with SDR

There are plenty of examples online (https://learn.adafruit.com/getting-started-with-rtl-sdr-and-sdr-sharp/overview) on how to receive images from NOAA satellites using SDR. This post will be about my experiences and ideas on how to improve the process I used. There are several items needed before having a finished image. These were the pieces used in my setup and some description about each. The first is the SDR hardware. Obviously this will be a requirement. It’s the typical DVB-T USB device most commonly used for SDR….

Read More Read More

Cutting through the smoke with Retinex

Cutting through the smoke with Retinex

This year, most of August was unfit for bike riding due to wildfire smoke in the air. There was a 10 day stretch where the visibility scale reached zero. Standing on the shores at Shilshole, the smoke was so thick that land wasn’t visible across the Puget Sound. I wondered if land was still visible from a digital camera, even though I couldn’t see it. There is an imaging processing technique call Retinex that is used to enhance the dynamic…

Read More Read More

RClone is the Rsync with the Cloud

RClone is the Rsync with the Cloud

RClone is an extended feature set to rsync which provides a way to use cloud storage for file backups. To install it, refer to this link https://rclone.org/downloads/. In my example I run these commands to download and install RClone. wget https://downloads.rclone.org/v1.42/rclone-v1.42-linux-amd64.deb sudo dpkg –install rclone-v1.42-linux-amd64.deb Next is to configure RClone to use the cloud service. I ran this command to do that. Refer to this link, https://www.hwrrobotics.com/tutorials/installingRcloneUbuntu14.04 or https://www.unixmen.com/install-configure-rclone-debian-8/ rclone config 2018/08/07 04:02:03 NOTICE: Config file “/home/local/.config/rclone/rclone.conf” not found -…

Read More Read More

FFMpeg motion detection

FFMpeg motion detection

FFMpeg motion detection offers a way to create videos that are smaller and shorter becuase it only captures changed scenes. This post discussed the topic, https://superuser.com/questions/984841/ffmpeg-remove-parts-without-motion. Here is the command I used based off of this conversation. ffmpeg -i “http://viewr1:viewr1@192.168.6.184/mjpeg/stream.cgi?chn=0” -vf “select=gt(scene\,0.004),setpts=N/(25*TB)” IPCam4_Motion.mp4 The one thing I noticed was the timestamp in the video is being detected as a scene change, this introduces a higher noise floor. I found that my lowest scene value to be .004. This site, http://www.bogotobogo.com/FFMpeg/ffmpeg_thumbnails_select_scene_iframe.php…

Read More Read More