search

technion / lol_dht22

A Raspberry Pi DHT22/AM2302 polling application
81 stars 64 forks source link

Data not good, skip #7

Closed speeskeek closed 6 years ago

speeskeek commented 7 years ago

Hi there,

I'm trying to debug my Pi (I'm building 3 zero's to be this: http://www.instructables.com/id/Raspberry-Pi-Temperature-Humidity-Network-Monitor/) - but I ain't getting any results from the sensors. I have 3 sensors (AM2302) lying around, and all the same (same store, same layout) - alle three no results ("Data not good, skip"). I had a raspberry zero running and working before with one of these sensors.

Where can I start to resolve this? Is it a dependency? is there a go low where it should high? is there something missing in the /boot/config.txt ?

shrx commented 7 years ago

Do you have WiringPi installed?

speeskeek commented 7 years ago

i's in dutch, but the last phrase is the most important: pi@temperatuur1:/sys/bus/w1/devices/w1_bus_master1/00-800000000000 $ sudo apt-get install wiringpi Pakketlijsten worden ingelezen... Klaar Boom van vereisten wordt opgebouwd De statusinformatie wordt gelezen... Klaar wiringpi is reeds de nieuwste versie.

that is wiring is already the newest version

I was trying now to manually read something, by going /sys/bus/1w/devices/... but can't find anything useful (w1_slave does not exist)

pi@temperatuur1:/sys/bus/w1/devices/00-800000000000 $ ls driver id name power rw subsystem uevent

woerty commented 7 years ago

You can't manually read the DHTs in the OneWire fashion as they are not real w1 devices. If the sensors don't work for me it has always been a problem with the wiring of the DHTs to the Pi. Try the shortest cable length you have to avoid noise.

technion commented 7 years ago

Do you definitely have the correct pin configured? I'm having a hard time coming up with something better than "works for me" without seeing your hardware.

speeskeek commented 7 years ago

@woerty : cable lenght is real short. Its the cable that came with it. About 5cm (2-3inch?). @technion : yes definitely the right pin. I alse recompiled with another pin, and rewired it to test, but no luck.

What should be in config.txt? What dependency should I check? Or reinstall?

EDIT: the sensor, wiring, .. are ok, becouse the same sensor, wires, and the same RPi Zero where used before and it workes flawless for some weeks. Now I was editing the distro to make 3-4 copies of it.

woerty commented 7 years ago

You do not have additional software installed? I had problems reading DHTs when I had CPU intensive software installed such as motion etc. For the reading the timing is crucial.

speeskeek commented 7 years ago

Not that I'm aware of, need to check cpu usage if there is something weird using cpu

speeskeek commented 7 years ago

hi there,

the process w1_bus_master1 is taking some CPU load (even when not trying to read). the load is indeed to high... coused by ? (it's a rip Zero doing nothing, except me running over ssh top )

top - 07:40:03 up 6 min, 2 users, load average: 0,28, 0,28, 0,16

speeskeek commented 7 years ago

reinstalled (same Rpi0) another distro (DietPi). same shit. but CPU load is better now.

technion commented 6 years ago

This is believed to be fixed in #9. Many thanks for your patience with this.