Help me with DHT11 sensor!!!



  • When i wanna use dht11 with my onion omega 2+, its give me only -255 value for all pins. Also i tried use 5v and 3.3v . Scheme and my terminal below. In Scheme i just use pin 1 instead 19 , and dht11 instead dht22
    dht-1.jpg
    terminal.png



  • ExpansionDock-IO.png

    Using the Expansion Dock with Omega2, running FW, 0.3.2 b233.
    Please see the image that shows the termination of pins. Let us choose PWM CH1, marked as pin 19. Let us check the current GPIO configuration.
    root@Omega-CCC9:/# omega2-ctrl gpiomux get
    Group i2c - [i2c] gpio
    Group uart0 - [uart] gpio
    Group uart1 - [uart] gpio pwm01
    Group uart2 - [uart] gpio pwm23
    Group pwm0 - [pwm] gpio
    Group pwm1 - [pwm] gpio
    Group refclk - refclk [gpio]
    Group spi_s - spi_s [gpio] pwm01_uart2
    Group spi_cs1 - [spi_cs1] gpio refclk
    Group i2s - i2s [gpio] pcm
    Group ephy - [ephy] gpio
    Group wled - wled [gpio]
    =>pwm1 is configured for pwm
    root@Omega-CCC9:/# dht-sensor 19 DHT11
    humidity: -255.000000
    temperature: -255.000000
    =>We get the wrong readings. Let us reconfigure pwm1..
    root@Omega-CCC9:/# omega2-ctrl gpiomux set pwm1 gpio
    set gpiomux pwm1 -> gpio
    =>And verify pwm1 has changed to gpio.
    root@Omega-CCC9:/# omega2-ctrl gpiomux get
    Group i2c - [i2c] gpio
    Group uart0 - [uart] gpio
    Group uart1 - [uart] gpio pwm01
    Group uart2 - [uart] gpio pwm23
    Group pwm0 - [pwm] gpio
    Group pwm1 - pwm [gpio]
    Group refclk - refclk [gpio]
    Group spi_s - spi_s [gpio] pwm01_uart2
    Group spi_cs1 - [spi_cs1] gpio refclk
    Group i2s - i2s [gpio] pcm
    Group ephy - [ephy] gpio
    Group wled - wled [gpio]
    =>Let us try again..
    root@Omega-CCC9:/# dht-sensor 19 DHT11
    humidity: 87.000000
    temperature: 28.000000
    => Put the pwm1 back to pwm
    root@Omega-CCC9:/# omega2-ctrl gpiomux set pwm1 pwm
    set gpiomux pwm1 -> pwm
    => And try..
    root@Omega-CCC9:/# dht-sensor 19 DHT11
    humidity: -255.000000
    temperature: -255.000000
    =>Once again, put pwm1 to gpio.
    root@Omega-CCC9:/# omega2-ctrl gpiomux set pwm1 gpio
    set gpiomux pwm1 -> gpio
    root@Omega-CCC9:/# dht-sensor 19 DHT11
    humidity: 87.000000
    temperature: 28.000000
    => Try DHT22
    root@Omega-CCC9:/# dht-sensor 19 DHT22
    humidity: -255.000000
    temperature: -255.000000

    The DHT11 usually have 3v-5v operating range, with 5v5 specified as the max voltage. I used 3v3, not 5v; using 5v would probably damage the 3v3 inputs of Omega2. Also, the DHT11 I have already has the pull-up built onto the assy.
    Note: I have only 3 days hands-on with Omega. I could be wrong in the commands and config above.


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