Analogue Weather Display

[Gina]

I've been giving a lot of thought as to how to make vertical linear gauges and it's not trivial.  The easiest sort of dial is just a servo motor with pointer fitted directly to it and covering 180°.   Also, a stepper motor with pointer directly attached giving 360°.  Coaxial dials like a clock aren't too difficult - I have already used this principle in actual clocks.  Servo driven dials are absolute but stepper driven ones are relative and need setting to a known position first.

I'm thinking I might make a relatively simple setup to start with - I could make more detailled data available on computer eg. simple numerical data via USB and Serial Monitor.  So... what do I really want to know and see at a glance?  Well, for a start what I can see now which is water level in sump and very rough wind direction and strength by looking out of the window at the wind vane and anemometer.  I have a habit of designing rather complicated projects and then they take too long to do and I get a bit tired of them.  Far better to do some simpler projects and get them finished - that I know  but I'm having trouble taking it in

New list of much reduced weather data dials :-

1. Water level in sump
2. Wind direction
3. Wind speed
4. Outside temperature
5. Outside humidity
6. Wind chill temperature
7. Rainfall rate
8. Rainfall

The last two would be nice but a look out of the window will tell me if it's raining and how hard.  I've added wind chill having looked at my weather station web site data and realised it would be nice to know how cold it will feel if I go out

OMG... there's still 9 items in the list - too many!  I'm still at it, aren't I - getting above myself !  I need to prune that list and consider adding extra items later - perhaps.  Right then - I'll start with just the first three items

[Gina]

Next thing to think about is the layout.  I like big and bold and dials that are easy to read and an aesthetically pleasing design would be nice too.  Over to SketchUp then...  Back in a while...

[Davey-T]

Could you abandon the electro / mechanical version and use Arduino LCD  displays, either showing advancing bars, percentages or actual readouts, don't know if they can display different coloured bars going from green to red maybe for water level.
Or just one LCD that you can switch from one thing to another.

Dave

[Gina]

I don't want to because it's difficult to get a large enough display and enough contrast in daylight.  I had considered it.

[Icosahedron]

I'm sure an Arduino tft display will provide enough contrast. Decent sizes are avaiable, but probably not big enough to display all the data at the same time.

Another electro-mechanical option is "cluster motors", available from eBay. They are stepper motors that can be driven directly by a CMOS output, no driver is required. They are driven differently from conventional stepper motors in that the phase angle between the two waveforms is 60 in place of 90 degrees. You would have no problem 3D-printing dial indicators.

[Icosahedron]

I've thought of another option: A tft display is driven by the SPI bus making it possible to have a number of displays.

[Gina]

I've had a look at these online.  The contrast may be alright and SPI connection is good but the size is smallish for affordable units.  I could use one for the terperature and humidity though displayed as digital and maybe alternating between the two.  I shall be viewing the display at around 3 or 4 metres so it wants to be a decent size.  I might buy one and see what it's like, though I did say I wouldn't buy anything that wasn't essential this month.  I know the cost is relatively low but I'm afraid that once I start buying non-essentials I won't stop and a fiver here and a tenner there do add up.

[Gina]

I think I shall be going for TFT displays for some of the gauges.  Just need to work out how to use them.  I know how to do bar graphs but not sorted out text yet.

[Stub Mandrel]

Mechanical solution is a white cylinder with a red triangle painted or wrapped around it behind a window. Although the top of the indicator line will be angle, you get an 'analogue' vertical line that moves up or down as it rotates. Another option is a band painted red

[Gina]

Thanks Neil   Had thought of a band but not the cylinder

[Gina]

Having resurrected my Arduino Based Weather Station I have started thinking about this display as well.