Check DS18S20 from dallas (Maxim) and SHT11 from sensirion or the lm35 circuits from national. The two first ones are discussed in other posts in this forum.
Hi Pete,
what im looking for is something exactly like the SHT11, but i dont know his price yet...im projecting an data logger with temperature, humidity and pressure, but have to be small and the most cheaper possible.
Hi there,
I do not consider that connection to mcu is such a bad thing, per se. You can use the mcu to calculate the dew point (using temperature and humidity information from the SHT11).
The very very low cost humidity sensor will be a small piece of wood (or celuloid) . Read the attach article how you compute the air RH base on wood resistance. Even if I think that you will not use this "sensor" it's interesting from the theoretical point of view.
hello,
in a project for a datalogger we used a honeywell humidity sensor (HIH 3610). We made good experiences with it. Look at:
h**p://content.honeywell.com/sensing/prodinfo/humiditymoisture
Hi there,
I do not consider that connection to mcu is such a bad thing, per se. You can use the mcu to calculate the dew point (using temperature and humidity information from the SHT11).
well, I say *bad* because he wants a simple humidity sensor. After I read that he also want to have pressure sensor, so the microcontroler is an almost obliged way...
but by "simple" humidity sensor, the phillips pseudos capacity, inclused in a multivibrator, are the simplest schematics, and analog ones for those who dont want to make digital measures !
Hi!
sht-11 and sht-71 is very good devices.You can order samples from sensirion.If you request samples, don't forget to request sample codes for popular mcu's.I requested code for pic16f877 and if somebody interests i can send it via e-mail.
I'd like to receive a circuit diagram for interface PIC16F877 (microcontroller) with SHT11 and code CCS-PIC16F877 ? Or Serial Port PC ?
I need routines for reading the SHT11 sensor (humidity and temperature) with a PIC16F877 or PIC16F628 microcontroller.
Can you help me ?
Hi!
sht-11 and sht-71 is very good devices.You can order samples from sensirion.If you request samples, don't forget to request sample codes for popular mcu's. I requested code for pic16f877 and if somebody interests i can send it via e-mail.
H1 humidity sensor. but this sensor's output is a capacitance between 112pF (at 10% RH) and 143pF (90% RH) Its curve is not linear so we'll use a simple table to convert the A/D reading to the correct RH-value. Capacitance to frequency conversion is done with a simple 555 timing circuit. This frequency is fed to the PIC's T1_CLK