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Author Topic: Analogue Temperature Display  (Read 1927 times)
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Stratford Upon Avon, UK
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This is an analogue display unit for inside/outside temperature. It is built into an oak cabinet which also holds an valve amplifier (for Ipod & DAB radio), it is intended to be used in a conservatory. It displays Temperature now, max temp, min temp and rate of change of temp for internal & external temperature. The dials are updated every 5 mins and the temperature values and UNIX time are logged to an SD card.

I wanted analogue dials so originally spec'd aircore movements but had problems in sourcing. Next idea was to use one turn winch servos but these were noisy, had low position resolution and have large deadbands. In the end I used analogue servos for most dials (with 180 degree pointer movement on 320 degree dials). The two large temp displays needed more than 180 degrees so I made servos with external motors and ceramic 360 pot and used the analogue control boards from some old servos.

The servos have a common -ve rail which is switched by a MOSFET so the arduino can set the needle position and then freeze them by turning off the power.

Originally the design used solar cells and batteries but I changed this to mains adaptor as I needed to be able to charge the ipod from time to time (the valve amp charges the ipod but is very power hungry), the arduino controls a triac to turn on/off the amplifier and also a DAB radio, either via a push of the power switch or if the ipod has not been used for a while.

The circuit is very simple, arduino plus adafruit datalogging card (for SD card & RTC), two DS1307 temp sensors and a mosfet to switch the servos power, a triac to switch the valve amp power. I ran out of pins so the power switch and demo switch are used on a single analogue input pin with resistor ladder. A 7v5 laptop PSU powers the arduino and DAB radio and a simple linear 5v reg powers the servos.

Hardest part was turning the small shafts on a lathe which connect the servos to the dial pointers.




* Palm_House_8.ino (20.9 KB - downloaded 14 times.)
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Very impressive, very nicely finished !! A+ smiley
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Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
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this is beautiful. im very impressed.
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North Queensland, Australia
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Very nice, I like the antique look, would go well with a tworse key next to it.

Is that one of the speakers to the right of it ( first picture )? similar style lattice.
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Stratford Upon Avon, UK
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Thanks for all the comments.

The speakers are 1970's Pioneer CS-05 speakers (an eBay find!)

The Tworse Key is a great project which would be complimented by;
http://steampunkworkshop.com/telegraph.shtml
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Port Elizabeth, South Africa
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I LOVE analogue displays. Always thought I would've enjoyed the 50's cause it was simpler - I think it is a magical time...but I'm 30 years old and what do I know about that time.

Looks brilliant!
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"The really amazing thing is how many people are successful with their Arduino projects considering the fact that so many of them do not have a technical background.  A lot of them seem to try, and succeed with, projects that no sane engineer would even attempt." - floresta commenting on the proper use of LCD displays

field road, jupiter creek
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Man, that is the freakin coolest thing I've EVER seen here!

Back in the day, I built a "Lunar Lander" simulator.

My grand dad had a car wreckers and let me pull old spedo's out of dashboards.
I coupled DC motors to the spedo inputs and controlled the motors with PWM circuit built from 74LS90 counters and 74LS85 comparators.

Ran the code on my SYM-1.

Had a spedo for fuel, altitude and velocity.

It was SO NOISY!

But that was part of the fun!

This is way and beyond cooler though!

Great work man!

Great work!
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By just watching the pictures it's hard to believe you used any electronics, it looks great !
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