A while back the ship’s NWS mechanical barograph gave it up, thread here(Electronic Barograph), turns out the NWS has switched to digital barographs. I haven’t laid eyes on it but NWS tells me one is one the way to the ship.
I also thought it would be good to have one at home and during my research the lowest price I could find was about $240, but pressure sensors can be had for about $10. So I thought I’d see if I could get one working at home. A RPi with WiFi can be had for about $10. I paid under $50 for a Pi 3 B+ which includes power supply and case. I hooked up a TV with HMDI from the guest room for a monitor and bought a cheap keyboard. It makes a usable standalone computer by itself
Here is the result, this is screen shot. The missing plot is when the power went out in high winds. The plot is done using Matplot. The Python3 script can be seen on the left. I didn’t write the scripts, it’s from using cut and paste from the internet, a little tweaking was needed here and there to get it to run.
Here is the “headless” (no monitor, keyboard or mouse), Raspberry Pi with a ribbon cable to the bread board.using a VNC viewer to see it from my laptop.
Here is the BMP280 pressure/temp sensor and a SHT31-D humidity/temp sensor on a breadboard, a little soldering was required. The comms protocol is i2c.
Next I going see if I can get temp and humidity (from the SHT31-D) on the same graph.
Very nice work. The capabilities of that Raspberry Pi thing amaze me. We have used them to keep purifiers and air driers functioning when heat has overcome certain modules of the OEM controls.
Looks like you’re getting close. If I remember correctly you can find a bunch of pi based wx stuff on GitHub also simple AIS and charting solutions.
Using GitHub is good advice. I took a very narrow trial and error path to get the graph up and running, I copied from how-to advice sites found via google.
Now that I have a pressure graph working I think I need to step back and get a better handle on the basics before I go forward.
Great job with the Raspberry PI, breadboard and all!
I donot know whether you are still looking for one but here we consider the Meteograf Barograph with paper roll the best. It runs on a household battery, weighs 500 gr and costs in the US 890 dollars which is cheap compared to the European price tag of € 955 which amounts to 1110 dollars. You can take it easily from the ship to your home and v.v.
The Starpath Marine Barometer app for iOS and Android is according the website rather accurate. However, it only works on an iPhone 6 and 6 plus which have a pressure sensor on board and at least iOS 11.
Not looking, the ship was provided with a digital barograph from NWS (National Weather Service). The three hour pressure trend is required for the synoptic observations.
As far as at home this RPi is working out nice. The BMP280 sensor is very sensitive, I can see the graph plot jump when wind gusts hit the house. I haven’t really checked the accuracy, but it seems more then adequate for home use. The specs say +/- 0.2 mb.
sorry, just registered here so I’m novice
I’m interested in realize this nice project
I’ve already a couple of Raspberry Pi3 I use with OpenCPN
There is someone able to send me more informations like diagrams and the software to realize this barograph?
Thank you in advance and HAPPY NEW YEAR to all the readers
You’re probably going to have to go looking for what you need. There’s enough info in the first post as to what to search for.
I used a BMP280 and i2c comms protocol. For the set up in the photos you’ll need a small breadboard and some jumper wires. The pins on the BMP280 breakout board will need to be soldered.
As far as software, there are various ways this can be done but there’s lots of info on how to use python3 scripts which can be found on the internet.
I’m not using the setup in the photo anymore, gave it to some high schools kids to play with.
Current setup writes data to ThingSpeak so I can see it on my phone etc.
Going to close this thread. Any further discussion better to start a new thread,