Read car AC display using Arduino
hi all,
i'm trying connect arduino car ac display (please see picture below). ac display @ bottom. there 5 wires going display.
here info display:
(blue/red wire) - display dim when head light comes on. tested wire meter , voltage 0v when headlight off, ~12v when headlight on. want plug wire arduino board , i'm going use voltage regulator bring voltage 5v.
(green wire) - acc wire. time voltage when car on. use power arduino. voltage ~12v. question: safe use ~12v power supply arduino?
(yellow/red wire) - there knob control fan. tested wire , voltage range 0v - 5v. 0v means @ lowest setting, 5v means @ highest.
(blue wire) - i'm getting confuse. i'm not sure if data wire (serial) or voltage. when tested wire pluging arduino (analog), voltage range 0v - ~1025v. loop 0 - 1025v, starting 0v. when plug wire arduino using serial, no data. i'm lost @ point. great.
(black wire) - of course ground wire.
any suggestions, appreciated.
thanks reading.
i'm trying connect arduino car ac display (please see picture below). ac display @ bottom. there 5 wires going display.
- blue/red - dimmer
- green - acc power
- yellow/red - knob temp (0-5v) control
- blue - data (i believe data wire.)
- black - ground
here info display:
(blue/red wire) - display dim when head light comes on. tested wire meter , voltage 0v when headlight off, ~12v when headlight on. want plug wire arduino board , i'm going use voltage regulator bring voltage 5v.
(green wire) - acc wire. time voltage when car on. use power arduino. voltage ~12v. question: safe use ~12v power supply arduino?
(yellow/red wire) - there knob control fan. tested wire , voltage range 0v - 5v. 0v means @ lowest setting, 5v means @ highest.
(blue wire) - i'm getting confuse. i'm not sure if data wire (serial) or voltage. when tested wire pluging arduino (analog), voltage range 0v - ~1025v. loop 0 - 1025v, starting 0v. when plug wire arduino using serial, no data. i'm lost @ point. great.
(black wire) - of course ground wire.
any suggestions, appreciated.
thanks reading.
careful! you doing things can damage arduino!
the acc wire supplies 12v... yes, used power arduino, should aware can "noisy" 12 volts , might have voltage drops or voltage spikes. others have written this. not sure best advice this, in theory should work. i think i've read of others putting voltage regulator in between 12v , arduino save arduino battery weirdness.
using 5v voltage regulator drop 12v signal sense detection on arduino not idea. it really, bad idea. you should not that. what should use optoisolator switch. have 12v signal switch optoisolator on/off. have digital i/o pin on arduino connected ground on arduino. so when 12v signal there, switch on, , current flows digital i/o pin ground. when 12v signal not there, no current flows digital i/o pin ground. your use of voltage regulator plain wrong. you not want add voltage arduino's input pins voltage source. they aren't designed that. a voltage regulator generate heat burning off excess voltage as... well... heat. it designed power - not using input signal. it might work, might fry arduino.
the analog pins on arduino designed 0 5v. the value getting not voltage. the value range between 0 , 1023, corresponds 0 5v. so if read value of 512, approximately 2.5v.
as suspect data wire... it's not compatible serial signal can hook serial pins on arduino. you need oscilliscope or digital probe capture , analyze highs , lows figure out signaling , protocol. not can without one, unless can somehow find specs on protocol used. and if ttl serial or rs-232 or rs-485 signal, tapping arduino affect signal , make not work.
is fan knob potentiometer 3 wires? if so, best bet might disconnect fan knob ac unit , instead connect arduino read, use digital potentiometer ic (like ds1308 example) send digitally controlled output ac unit. this let override fan setting arduino.
the acc wire supplies 12v... yes, used power arduino, should aware can "noisy" 12 volts , might have voltage drops or voltage spikes. others have written this. not sure best advice this, in theory should work. i think i've read of others putting voltage regulator in between 12v , arduino save arduino battery weirdness.
using 5v voltage regulator drop 12v signal sense detection on arduino not idea. it really, bad idea. you should not that. what should use optoisolator switch. have 12v signal switch optoisolator on/off. have digital i/o pin on arduino connected ground on arduino. so when 12v signal there, switch on, , current flows digital i/o pin ground. when 12v signal not there, no current flows digital i/o pin ground. your use of voltage regulator plain wrong. you not want add voltage arduino's input pins voltage source. they aren't designed that. a voltage regulator generate heat burning off excess voltage as... well... heat. it designed power - not using input signal. it might work, might fry arduino.
the analog pins on arduino designed 0 5v. the value getting not voltage. the value range between 0 , 1023, corresponds 0 5v. so if read value of 512, approximately 2.5v.
as suspect data wire... it's not compatible serial signal can hook serial pins on arduino. you need oscilliscope or digital probe capture , analyze highs , lows figure out signaling , protocol. not can without one, unless can somehow find specs on protocol used. and if ttl serial or rs-232 or rs-485 signal, tapping arduino affect signal , make not work.
is fan knob potentiometer 3 wires? if so, best bet might disconnect fan knob ac unit , instead connect arduino read, use digital potentiometer ic (like ds1308 example) send digitally controlled output ac unit. this let override fan setting arduino.
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