Skip to content

Instantly share code, notes, and snippets.

Avatar

Phill Paraphraser

  • Cootamundra NSW Australia
View GitHub Profile
@Paraphraser
Paraphraser / RPiWiFiFreeze.md
Last active Jun 1, 2021
Does your Raspberry Pi's Wireless Interface freeze? This may solve it.
View RPiWiFiFreeze.md

Does your Raspberry Pi's Wireless Interface freeze?

My Raspberry Pi 4 kept losing its wlan0 interface. I could usually reconnect via Ethernet but, from time to time, I noticed that the eth0 interface would also go walkabout.

I tried a lot of things but the one described here seems to have cured the problem. I have no idea why it works. It just does.

Step 0 - are you a Windows user?

The script shown in the next step should be created on your Raspberry Pi. Please do not make the mistake of selecting the text, copying it into a text editor on your Windows machine, saving the file, and then moving the file to your Raspberry Pi. Unless you take precautions, Windows will add its 0x0d 0x0a (CR+LF) line endings and those will stop the script from working properly on your Raspberry Pi.

@Paraphraser
Paraphraser / IOTstackPullRequest.md
Last active Apr 19, 2021
Preparing IOTstack Pull Requests
View IOTstackPullRequest.md

Preparing a Pull Request for IOTstack

If you want to fix a bug or propose an enhancement for IOTstack, you will need to prepare a Pull Request (PR).

Please don't try to do anything in this gist inside an ~/IOTstack folder on a Raspberry Pi that is also being used to run your Docker containers. It's easy to get confused and you could accidentally break your own working IOTstack.

You can do everything on the same Raspberry Pi that is running your IOTstack but it's usually easier to work on a desktop or laptop. If you accept this advice, there's no risk of breaking your running IOTstack.

This guide barely scratches the surface of Pull Requests. There is lots of advice on GitHub and Google will find plenty of hits for any question you might have.

@Paraphraser
Paraphraser / InfluxDB security under IOTstack.md
Last active Feb 26, 2021
Enabling authentication in InfluxDB for SensorsIot/IOTstack
View InfluxDB security under IOTstack.md

Tutorial: Enabling authentication in InfluxDB

Assumptions:

  • you are running SensorsIot/IOTstack with InfluxDB as one of the containers
  • you want to enable authentication for your InfluxDB databases.

Note: This tutorial is specific to SensorsIot/IOTstack.

Definition:

@Paraphraser
Paraphraser / Enabling UDP support in InfluxDB.md
Last active May 21, 2021
Enabling UDP support in InfluxDB for SensorsIot/IOTstack
View Enabling UDP support in InfluxDB.md

Tutorial: Enabling UDP support in InfluxDB

Assumptions:

  • you are running SensorsIot/IOTstack with InfluxDB as one of the containers
  • you want to enable UDP support
  • your goal is to log traffic arriving on UDP port 8086 into an InfluxDB database named "udp".

This tutorial is specific to SensorsIot/IOTstack. You're on your own if you "get creative" and choose different ports or database names.

@Paraphraser
Paraphraser / TheRetainFlag.md
Created Sep 18, 2020
MQTT and the retain flag
View TheRetainFlag.md

Tutorial: MQTT and the retain flag

Assumptions and setup

This tutorial assumes:

  • a single computer (like a Raspberry Pi)
  • MQTT broker (like Mosquitto) running
  • the mosquitto_pub and mosquitto_sub commands are available.
@Paraphraser
Paraphraser / CalculatingBarometricPressureTrend.md
Last active Jan 2, 2021
Calculating barometric pressure trend
View CalculatingBarometricPressureTrend.md

Calculating barometric pressure trend

This gist is a response to a Discord question. It explains my approach to deciding whether barometric pressure is rising, falling or remaining steady.

I do the trend calculation in Arduino (ESP8266) code. I tried to mimic the idea of setting the reference needle on a real barometer, waiting an hour, then seeing which way the pressure needle had moved with respect to the reference. The wrinkle is that "the last hour" is a moving window that updates every 10 minutes.

The BMP085 sensor is polled every 10 minutes. Until there are six observations (eg after a reboot) the code returns "training".

After that, the code does a least-squares regression on the last six observations (ie the last hour of data) to find the linear equation of best fit. In effect, the algorithm assumes that knowing the time (independent variable on the X axis) at some point in the past hour would permit the pressure at that time (dependent variable on the Y axis) to be estimated with some degree of

@Paraphraser
Paraphraser / NodeRED_MidnightredTheme.md
Last active Dec 8, 2020
Recipe for installing Node-RED Midnight-red theme under IOTstack
View NodeRED_MidnightredTheme.md
@Paraphraser
Paraphraser / MQTT_Node-Red_Influx.md
Last active Jun 12, 2021
Efficient recipe for getting MQTT data into an InfluxDB database using Node-Red
View MQTT_Node-Red_Influx.md

Recipe: from MQTT to InfluxDB via Node-Red

Introduction

Getting data produced by IoT sensors into a database is practically a mandatory step before effective visualisation (eg dashboards).

This recipe shows you how to get an MQTT payload into an InfluxDB database using three Node-Red nodes. It makes the following assumptions:

  • A client device of some kind publishing data to a topic via the MQTT protocol;
  • Mosquitto (MQTT broker);
@Paraphraser
Paraphraser / RPi_local_NTP_servers.md
Last active Jan 18, 2020
Configuring Raspbian to use local time-servers
View RPi_local_NTP_servers.md

Configuring Raspbian to use local time-servers

The case for using local time-servers

Out of the box, Raspbian gets its time from NTP servers in the debian.pool.ntp.org domain. You can confirm this via:

$ timedatectl show-timesync
...
ServerName=0.debian.pool.ntp.org
@Paraphraser
Paraphraser / run_RPI4B_from_SSD.md
Last active Apr 30, 2021
Run a Raspberry Pi 4B from an SSD connected to a USB-3 port
View run_RPI4B_from_SSD.md

Run Raspberry Pi 4 from SSD

Deprecation notice (2021-03-08)

The material in this gist is a bit out-of-date and will soon be withdrawn.