I tried to make a simple project with Attiny85 chip and DHT11 sensor. After 2 days of struggle, made it finally work, but not quite as expected. TinyDHT library does work, while DHTNEW does not.
I wonder,
- what can be changed to make any of the libraries work at lower clock rate?
- how to make DHTNew work?
My results so far:
with TinyDHT:
- @ 16 MHz works nominally, showing valid T/H values (if I breathe on the sensor, it shows 95-99% humidity)
- @ 8 MHz, shows nothing (either nan, or zeros)
- @ 1 MHz, shows temp/hum as 5, 5 (or 50, 50, can't tell)
with DHTNEW:
- @ 16 MHz returns SENSOR_NOT_READY
- @ 16 MHz with
mySensor.setDisableIRQ(true);-> WAITING_FOR_READ at first, then nothing (nan or 0) - @ 8 MHz WAITING_FOR_READ at first, then TIMEOUT_C
- @ 8 MHz with
setDisableIRQ-> always TIMEOUT_C - @ 1 MHz always TIMEOUT_A
Here's the setup on photo and as a scheme. Arduino UNO works as a programmator for Attiny chip, as shown in this tutorial. After I upload the code to Attiny85, the chip starts working normally, and there's no need to disconnect the Arduino board. (For actual work, I disconnect it, connect 5V power, and it works the same way.)
Settings in the IDE:
- Board: Attiny25/45/85
- Processor: Attiny85
- Clock: Internal from 1 to 16 MHz
- Programmer: Arduino as ISP
How I test this:
- change clock frequency
- run Tools -> Burn bootloader
- run Sketch -> Upload
- wait till upload ends (RX/TX diodes stop blinking)
- the LED on breadboard blinks me the numbers
millis()needs to work). Did you check that a blink sketch blinks at the expected frequency when you change your clock settings? – Mat Nov 30 '20 at 9:40