Project Builder - LED Barometer

Assuming you will be using the correct type of ready-made pressure transducer, the manufacturer should be able to supply circuit diagrams to interface it to one or more types of common electronic inputs - one of my favourites is 4-20mA. There is a very good article on the RS web site that explains all about them and how to use them.

I wonder what sort of display you have in mind? This will determine the type of output you require from the interface. A column of LED's is probably as simple as it gets, although a circle of LED's with a pointer of smaller LED's could be good too. At the other end of the scale you could go for a centralised 3 or 4 inch LCD TV screen showing short video sequences of different types of weather ranging from tsunamies to tropical jungles, the south pole in winter to desert scenes with camels, etc.

If you are thinking of making it battery-powered then I would avoid using too many LED's - or, alternatively, making it so that it only switches itself on when a person in the same room is detected. You could use a suitably-rated 'brick' mains power supply as used with laptops, but I wouldn't be happy with the mains lead going up the wall. If you can hide the cable behind a TV set or whatever, then fair enough.

I can't help thinking that a Raspberry Pi or an Arduino would be good, in fact there are a few 'weather station' add-ons available. A lot depends on how you will be approaching this. Do you want to learn lots about electronics by buying all the individual components and soldering them all to a piece of Veroboard? Or do you want to learn how to program e.g. a Raspberry Pi-based system?

I hope I havn't put you off with all the above to think about! I don't live anywhere near London so face-to-face discussions might not happen and I packed all the Zoom equipment away a couple of years ago...

Good Luck, Chris (short for Christopher)

Is this a project that you want to be public and open source or do you have hopes of making a commercial product with it.

If it's the first then publish more detail and you will get suggestions and maybe a collaborator.

If you want the design to be your commercial property then you won't get much help without paying.

It sounds an interesting idea.

MK

Hi Chris

Thank you for your considerable email, I appreciate you taking the time and for the guidance you have included. To begin with, I am hoping to make a relatively simple system that would employ several coloured LEDs, perhaps fitted into a wooden panel, with some coloured, jewelled lenses fitted over the LEDs.

I would like to develop a circuit that would produce several outputs in responses to the previous last three hours' pressure variance, based on traditional pressure forecasting measurement principles.

LED Scheme:

Static Green - Steady

Static Yellow - Rising Slowly becoming Flashing Yellow - Rising Rapidly

Static Blue - Falling Slowly becoming Flashing Blue - Falling Rapidly

Flashing Purple - Storm Watch (Rapid Pressure Fall over a period of time)

Flashing Red - Severe/Deep Strom Warning (A continued, rapid pressure fall from 1000 hPa or below over a period of time)

I may also look at incorporating some audible warning output signal and perhaps a relay switching sound effect, or even a old relay, each time an LED changes status - to create a kind of old-fashioned switching noise. A unit that looks old fashioned cosmetically, though employs modern-day technology within.

Would like to try and find a local collaborator potentially to help realise this project. In the event of finding a suitable collaborator, would be happy to explore/discuss meeting the full cost of materials and practical time given, if the overall project cost is reasonable.

Best regards,

Spencer

Hi MK

Thank you for your email.

At this stage, the design would be for personal use.

Many thanks

Spencer

I like this idea more and more! Flashing Red would obviously have to be accompanied by the Enterprise klaxon, Static Green with Kirk asking "Spock - what's the weather like today?" followed by a suitable answer e.g."Fair to middling, Captain, average temperature will be nought point 03308932 degrees Fahrenheit warmer than yesterday" or, if Spock said "It's raining heavily* Captain" followed by Kirk saying "On Screen" whereupon the rectangular display would switch to a light grey background with water dripping down it - Know what? I think I may be getting a bit carried away here. There used to be lots of digitised sound effects all over the internet, might be worth investigating.

* At first I used two different words instead of 'raining heavily', initials P D. I then though that if I left it like that I'd probably get chucked off Element 14...

From your detailed description in your reply to  electronicbiker I think your best bet would be to use a string of neopixels controlled by an arduino . You will need a pressure sensor as well.

The neopixels are cheap and will allow you to have any colour for any LED and pretty much as many as you like.

Arduinos are good for simple projects with a lot of support on the web. You could make your own control board or use one of dozens of alternatives if you don't fancy the Arduino.

If you want to go wild you could have a column display of  pressure a bit like a zoomed in mercury barometer. 

https://thepihut.com/collections/adafruit-neopixels

You can buy neopixels from Aliexpress very cheaply - either loose (requiring assembly onto a pcb) or on tape (ready to connect to a microcontroller.).

MK

Perhaps this Arduino project is something similar to what you are trying to do ?

https://github.com/willemsphoto/Barometer/blob/main/redled-barometer-box.pdf

Also perhaps take a look at Natasha's series here on how to animate NeoPixel LEDs with a micro:bit

/learn/learning-center/stem-academy/microbit/microbit-tutorial-videos/b/blog/posts/animating-leds 

Thank you, MK.

Thank you for this information and corresponding links, Dave.

Thanks. :-)