Receive temperature, 433 MHz sensors, with RTL-SDR

In my underfloor heating project, using Node-RED, I have to have one sensing thermometer per room/zone, seems to be 8 in total, so therefore it would be nice with a wireless battery sourced device with good resolution and frequent updates.

During the test phase I used a Z-way device but the resolution was pretty bad. Another device mentioned is the Ruuvi tag but since it's a bluetooth device the transmitting range could be better.

After some googling I went for 433 MHz devices.

Z-Wave on Raspberry PI

Updated 2023-02-23 !

Installing a Z-Wave controller on Raspberry Pi is much easier than You think.

The only add on You need is the Razberry Z-wave Shield and free software from the same site.

Underfloor heating with PID controller, NodeRed

In a former post I did some hacking/checking how our underfloor heating control system handled the valves, actuators, regulating the heat. 

Now it was time to do some tests with NodeRed(NR), with a PID controller, and a Shelly 1(S1) connected via WiFi and driving the actuator.

The actuators are in my case controlled by 24 VAC and the S1 accepts 110 - 240 VAC, 24 - 60 VDC and 12 VDC. So in this case it was simple to just add a rectifier and a capacitor, to the 24 VAC, to get approx 36 VDC to source the S1.

Calculate wind using U and V GRIB components, NodeRed, JS

Updated 2022-11-28 !

In a former post I showed how to download and extract data from forecast GRIB files but avoided to handle if the wind direction and speed was declared as U and V components, vectors. 

In this post I will extract wind data from a GRIB forecast file and use the U V components to calculate, and display, wind speed and direction at a chosen point. The data is visualized as graphs in a NodeRed dashboard.

Normally, using charts in NodeRed, the timestamp is taken from the time when the input message is created but here I will use the timestamp from the forecast, loading the whole chart in one go.

Internet speed measure II

New to Node-Red(NR) ? Maybe start with a simple application You direct can benefit from.

This application is measuring Your Internet connection at chosen intervals using speedtest.net and showing the result in a graph. If the speed is under a set value it will send You an e-mail.

Show the measured Internet speed in Apples Home app ?

Victron monitoring solution, Venus, on Raspberry

Updated 2022-09-18 !

Victron have a state-of-the-art monitoring solution used by the GX products. It can monitor their other system components such as inverter/chargers, solar chargers, shunts, and batteries both local and remote all over the world.

If you have a smaller Victron solution it is nice to know that the same software, Venus OS(VOS), can run on a Raspberry Pi(RPi) instead of the more expensive and versatile GX products.

Node-Red quick install

Updated 2022-08-14 !

Node-Red(NR) is Flow-based programming for the Internet of Things

This post isn't made as a complete install guide, there are several, just some links to the best information I have found.

The best thing is that even if you don't are a skilled programmer, but like logic flows, you can make really advanced things. It's pre-installed on some Raspberry Pi(RPi) distributions.

Running Node-Red with multiple instances ?

RS-232 with displays & AV equipment

The use case for this post is that a got a request from a customer where a commercial displays brightness, used for digital signage, should be put at a minimum when there is no people in the surroundings.

After some checking I found that on most displays, even on our own TV set, there is a connector for the RS - 232 protocol that accepts commands similar to the commands sent by the remote control.

A nice explanation on how it works is found here.

Davis PWS linked to pwsweather.com

If you are using Davis Personal/Professional weather stations(PWS) you will get a nice dashboard when you link your PWS to the Davis weatherlink(WL) site.

What you probably really miss is a forecast displayed together with your PWS data. The picture is showing a part of the dashboard at pwsweather.com(PW) after you have linked your PWS to the site.

An add on is that you via API:s can get both the current weather, forecast and other data free of charge, via the aerisweather.com(AW) site.

This post will handle the setup and also a Node-Red dashboard interfacing the aeris API.

Node-Red multiple instances, RPi

Updated 2022-07-04 !

On the same server/hardware you can have

• a test environment for Node-Red(NR), separated from production
• separated instances for different applications

Setup will follow for a Raspberry Pi(RPi) including how to auto start at power on.

A post for NR quick install.

Exhaust temperature measure, boat

Updated 2022-06-10 !

In other posts I blogged about a way to measure temperature with a Raspberry Pi(RPi), direct connected or via WiFi, together with the marine applikation SignalK(SK). In this post I will follow up with a short brief about the practical solution, measuring exhaust temperature in a boat and sending an alarm if the temperature exceeds a set value .

In "wet exhaust" systems it is very important that the cooling water, injected in the exhaust system, always is present otherwise major damages can follow.

If you wan't to avoid a RPi check this post with approved NMEA 2000 temperature sensors from Yacht Devices 

Raspberry 4 USB SSD boot in 60 seconds !

Updated 2022-04-16 !

Yes, it's really true ! Thats the maximum time it takes to write the Raspberry Pi(RPi) OS to a bootable USB SSD and maybe read this post ?

If you have a RPi 4 and a USB SSD or other USB drive, that works as a boot media, just use the RPi imager which can write the image direct to the USB  storage. But check this first.

Having an older RPi ? Use this post instead.

If you already have a SD card with working applications and you want to "transfer", copy/clone, them to a bootable SSD use this post.

Read and write NMEA files, Openplotter, Signal K

This post is written for those who runs Signal K(SK), or applications that indirect are using SK, and want to write log files that could be read for later use.

Other applications could be Openplotter which includes SK or OpenCPN for example interfacing a NMEA 2000 network via SK.

There are sample files within the SK installation which can be used, for testing purposes, before you have created your own log files from your boat trips. Check here at "Input file/data".

Read & write Linux, ext4, volumes with Windows & Mac

In an other post I explained how to access and edit the data on an USB attached drive with the Linux "standard" ext4 filesystem. 

In this post I will explain how to read, write or add files using Windows, File explorer, or Mac, Finder, without third party software !

You "just" need a Linux machine, but since you want to access an ext4 filesystem there probably are a machine in the surroundings ?

In this post I will use a "simple" Raspberry Pi(RPi) and the ext4 media attached to one of the USB ports.

Victron VE.Direct with Raspberry Pi/Signal K

Updated 2022-01-11 !

During my update of the cables going from the batteries, to the distribution panel and engines, I stumbled over the Victron SmartShunt(VSS). We had a 15 year old Mastervolt battery monitor but it didn't feel "true" and it wasn't at the right place in the boat. So instead of moving the old shunt we bought a VSS. 

Raspberry, edit config or add files before boot

The actual use case was that I have a Raspberry Pi(RPi) sourcing Vesselfinder with AIS data from nearby. I wanted to change/test a new configuration but on the other hand I didn't want to take the RPi down, during a longer period, since it's an online service.

So the solution was to make a bootable clone of the actual application and test with a second RPi. The major obstacle was that I then would have 2 hosts, with the same hostname, which will mess up the local network.

So how to change the host name on the cloned SD card before I'm using it in the second RPi ?

Another post on how to read and write Linux drives with Windows/MacOS

Raspberry, restart network, or reboot, at ping failure

Using a Raspberry Pi Zero(RPi), with wifi, I sometimes have problem that the WiFi connection is lost. This is due to that, at our boat, we are using the Teltonika RUT 240 router. The router just have one receiver/transmitter, LAN and WAN WiFi are shared, and in some use cases the WiFi will temporarily be disconnected. To restart the WiFi quick the following solution is used.

This post will cover a solution, a bash script, with inspiration from this blogpost, but with some fine tuning. 😉
 

Another way could be using the watchdog function, described here, with reboot.

SIGNL4, automated alerting with free mobile app

I'm involved in several projects where you, as quick as possible, want to get an alert if anything fails. After a lot of Googling I found SIGNL4.

They have several ways to create an alert, can involve a team, have a nice app and is free, up to 5 users, if you use the "STARTER" option.

In this post, as an example, I will show how I detect if my AIS receiver/dispatcher stops receiving AIS targets, sent to Vesselfinder, and how an alert is forwarded to the SIGNL4 app.

I'm using NodeRed on a Raspberry Pi to realize the function

Ring doorbell install and relay

The electrical install instructions for the Ring Doorbell maybe could be a little easier to find  ? 

So will give some links where you are connecting to

1. Internal doorbells
2. No internal doorbell but charging the battery
3. External relay, triggering "anything"
4. Wireless relay

Ring Device manuals are found here.

Homebridge made simple, HOOBS

Updated 2021-08-08 !

I have written several post about the HomeKit Bridge, Homebridge(HB), but if You want another simple way, with GUI, to handle the server and plugins the guys at HOOBS have done a nice software package.

I personally prefer the Homebridge "native" install, which seems to be updated more frequently.