Hi, i would like to ask why my temperature reading cannot constant show on the LCD display. normally when temperature increase, it will increase by 0.1,0.2..., right? but my one always change the temperature reading from 23.5C to 23.9C or 24.2C (example) but when i measure the temperature sensor output voltage, it constant. pls advise! thanks!
Re: temperature reading cannot constantly show on LCD dispal
And what kind of sensor do you have? Maybe its accuracy is more than 0.1 deg? Or maybe you've got some error in the algorithm of calculating the value of temperature?
Re: temperature reading cannot constantly show on LCD dispal
use lm35 transistor as temperature sensor
it comes in different rating and different resolution
then use a good ADC ic then get this data to the microcontroller for display
i uses this scheme and this works
Re: temperature reading cannot constantly show on LCD dispal
be more practical
use digital temperature sensor
use tmp 124 which supports spi protocol
pros
no adc needed
harware become simple
sense temperature upto 0.25 degrees
high response time
programmable ic
supports interrupts
16 bit spi
when i use it i can see its output on lcd changing 2-3 times pr second
u can free sample it from ti.com
Re: temperature reading cannot constantly show on LCD dispal
Hi!
Well i faced a similar problem and the reason was noise in the power supply circuit. That greately effects the stability of the readings. Specially if you are using the ADC refrence as the power supply. The simplest solution is to add one or two 100nf capacitors on the power supply line as close as possible to the microcontroller and the adc results will hopefully stabilize.
Regards.
Re: temperature reading cannot constantly show on LCD dispal
Hi blueroomelectronics!
Heating of the sensor may also be one of the reasons. By the way how are u driving this LCD. I cannot see any driver IC in the picture. Can u tell me the source of this LCD display from where it can be purchased.
Regards.
Re: temperature reading cannot constantly show on LCD dispal
could u pls post the lcd program over here i'm gr8 distress since my program is'nt working. infact any lcd program does not work.
i tried interfacing the lcd to other MCU's and it worked...