Category Archives: Geekiness

Athom Tasmota Button On/Off

I accidentally factory reset one of the plugs and the button stopped toggling the switch. This was the coffee machine – a slight catastrophe for the odd times it needed a manual toggle.

I found the athom page had a mystery “template” and worked out where to enter it on the tasmota. Job done.

{"NAME":"Athom Plug V2","GPIO":[0,0,0,3104,0,32,0,0,224,576,0,0,0,0],"FLAG":0,"BASE":18}

Configure Other, then put it in a the top and tick Activate.

Tasmota Auto Off

This took me a while the first time, then found I had to do it again and had to look it up once more. One kind person had already worked this out and it led me to this command in the tasmota console:

Rule1  ON Power1#state=1 DO RuleTimer1 1800 ENDON ON Rules#Timer=1 DO Power1 Off ENDON


Rule1 1

To enable the rule.

This rule will turn off thetasmota socket 30 minutes after it is turned on.

Of course, I should probably be doing that with Home Assistant now. Then I don’t have to go looking for the rule.

So that is what I did!

Home Assistant Templates

I have been getting to grips with Home Assistant (hassio). (This was after attempting, late at night and tired, to update OpenHab… It didn’t go well and though I had solid backups I knew I would need to do a full restore and have kept hearing about Home Assistant. I wanted to give it a try, and found it is so much better than OpenHab. I had everything OpenHab had and more in one morning of play. Everythign is so much easier).

So the more I got in to hassio the more I kept hearing about Templates. Hassio is well documented but there are no examples at all. I can read them but miss the point because, typiccally, I read too fast.

So when the Templating documentation said:

Templating in Home Assistant is powered by the Jinja2 templating engine. This means that we are using their syntax and make some custom Home Assistant variables available to templates during rendering.

I didn’t realise this meant “custom code”. That would have helped. Template = Custom Code in Jinja2!

I went in to the Developer Tools > Template and had a play (with the help of avideo by “Smart Home Junkie”) I found that I could easily get the value of things using {{ states(‘the_thing’) }} (I also found that the Dutch word for curly bracket is “accolade” which is way better to my ear).

With my new knowledge I made my first Template to show the current rate as a read only thing so I can display is safely.

  1. A name – this is what you look up later and is turned in to a spaceless name, this one would become current_rate
  2. The Jinja2 code
  3. Preview

I made a sensor called “Current electricity period” and magic happened when creating a dashboard.

I know it is basic knowledge, but I needed to make this first step. I think I am away now.

yfinance 0.2.3 on raspberry pi

I have a silly little script that checks the shares each day and sends me a telegram, but it stopped working. After an hour or so of analysis I determined that the version of yfinance on raspberry pi that I had, 1.74, was returning None on any call. If I upgrade to 2.3 on Windows (update pip,pip install -upgrade pip, then pip install –upgrade yfinance, it all starts working again.

Getting it to work on Raspberry Pi was not so simple. This is a record of what I did.

Show the currently installed packages in the venv

source ./.venv/bin/activate
pip list

Upgrade pip and try to upgrade yfinance

pip install --upgrade pip
pip install --upgrade yfinance

You get an error saying that rust is the wrong version. Doing sudo apt install rustc does not install a version of rust that is high enough. So you turn to rust istelf and use:

curl --proto '=https' --tlsv1.2 -sSf | sh 

Then follow the instructions. You need to kill the shell or read the message and source “$HOME/.cargo/env”. Then try to upgrade yfinance again.

pip install --upgrade yfinance

It now fails with:

error: command '/usr/bin/arm-linux-gnueabihf-gcc' failed with exit code 1
note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for cryptography
Failed to build cryptography
ERROR: Could not build wheels for cryptography, which is required to install pyproject.toml-based projects

So try to get gcc working. I read that installing gcc libffi-dev libssl-dev and python3-dev might help so did that, though I already had gcc and python3-dev installed so just needed this:

sudo apt-get install libffi-dev libssl-dev
pip install --upgrade yfinance

And THAT fixed it 😁so I now have yfinance 0.2.3 and yfinance works.

arduino as mqtt temperature sensor

My office gets pretty cold and I had worried that the heater would come on if it went below 5°C. This was until I went in there and discovered that the thermostat from Honeywell will not read lower than 5°C!

Now I have grafana I was wondering how to get a reading of the temperature in there. I have lot of kit kicking around from my arduino days so I thought I would give it a whirl. The aim was for the arduino to push the current temperature to the mosquitto broker on openhabian then read it out to influxdb and eventually to grafana.

I ended up using:

  • arduino uno
  • arduino uno ethernet shield
  • DS18B20 temperature sensor
  • 4.7 kΩ resistor
  • breadboard and leads


I used this to remind me how to get the temperature sensor working: Then with a bit of searching and playing around I got the whole kaboodle working. There was a lot of intelligent copy and paste and I have no idea how much of this is redundant but it bloody works (code below).

Weirdly, the graph sparklines did not work in the temperature display in grafana. helped me work out that I needed to do a GROUPBY in the query (I used 15m). You can see the result at the top of the page.

// First we include the libraries
// Temp Sensor
#include <OneWire.h> 
#include <DallasTemperature.h>
// Ethernet Shield
#include <SPI.h>
#include <Ethernet.h>
// Mqtt
#include <ArduinoMqttClient.h>
// Data wire is plugged into pin 2 on the Arduino 
#define ONE_WIRE_BUS 2 
// Setup a oneWire instance to communicate with any OneWire devices  
// (not just Maxim/Dallas temperature ICs) 
OneWire oneWire(ONE_WIRE_BUS); 
// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);

// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

// Set the static IP address to use if the DHCP fails to assign
IPAddress ip(192, 168, 0, 23);
IPAddress myDns(192, 168, 0, 1);

EthernetClient net;

MqttClient mqttClient(net);

const char broker[] = "openhabian";
int        port     = 1883;
const char topic[]  = "arduino/temperature/";

char clientId[] = "ToM_arduino_001";
char username[] = "openhabian";
char password[] = "averybigsecret";

const long interval = 1000;
unsigned long previousMillis = 0;

void setup(void) 
 // start serial port 
 Serial.println("Dallas Temperature IC Control Library Demo"); 
 // Start up the library 
  // start the Ethernet connection:
  Serial.println("Initialize Ethernet with DHCP:");
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    // Check for Ethernet hardware present
    if (Ethernet.hardwareStatus() == EthernetNoHardware) {
      Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
      while (true) {
        delay(1); // do nothing, no point running without Ethernet hardware
    if (Ethernet.linkStatus() == LinkOFF) {
      Serial.println("Ethernet cable is not connected.");
    // try to configure using IP address instead of DHCP:
    Ethernet.begin(mac, ip, myDns);
  } else {
    Serial.print("  DHCP assigned IP ");
  // give the Ethernet shield a second to initialize:

  Serial.println("You're connected to the network");

  // You can provide a unique client ID, if not set the library uses Arduino-millis()
  // Each client must have a unique client ID

  // You can provide a username and password for authentication
  mqttClient.setUsernamePassword(username, password);

  Serial.print("Attempting to connect to the MQTT broker: ");

  if (!mqttClient.connect(broker, port)) {
    Serial.print("MQTT connection failed! Error code = ");

    while (1);

  Serial.println("You're connected to the MQTT broker!");
void loop(void) 
 // call sensors.requestTemperatures() to issue a global temperature 
 // request to all devices on the bus 
 Serial.print(" Requesting temperatures..."); 
 sensors.requestTemperatures(); // Send the command to get temperature readings 
 Serial.print("Temperature is: "); 
 Serial.print(sensors.getTempCByIndex(0)); // Why "byIndex"?  
   // You can have more than one DS18B20 on the same bus.  
   // 0 refers to the first IC on the wire 
   // call poll() regularly to allow the library to send MQTT keep alives which
  // avoids being disconnected by the broker

  // to avoid having delays in loop, we'll use the strategy from BlinkWithoutDelay
  // see: File -> Examples -> 02.Digital -> BlinkWithoutDelay for more info
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    // save the last time a message was sent
    previousMillis = currentMillis;

    Serial.print("Sending message to topic: ");

    // send message, the Print interface can be used to set the message contents