Does anyone know of a good alternative to the DHT22 for temperature and humidity sensing on the Raspberry Pi?
The DHT22 works great, but the wire length can only be a few feet long before you start running into problems. I want to connect a temp/humidity sensor at about 15 feet away.
You can use some of 1-wire sensors, for example temperature>DS18B20 humidity>DS2438 or some else.
You can read more about 1-wire specification here
Related
I use this library over SPI to control some RGB Leds.
When using the Raspberry Pi 3, I have to set cpu_freq=250 on /boot/config, as far as I've understood, it has something to do with the bluetooth device running on the default serial port.
Now, using the Raspberry Pi Zero W I'm algo having to set that flag.
My questions is, what is the correct cpu clock for both Pi 3 and Zero W, and am I slowing my Pi performance by setting this flag?
I'm using MPU6050 IMU with the raspberry pi. I want to get data at a required frequency, for example, 200 Hz that is I want data at every 0.005 seconds. How do I go on to accomplish this? I'm using i2c for serial communication. Feel free to suggest any other method by which I can get this done.
I'm trying to talk via I2C to the gyro sensor MPU6050 which sits on a GY 521 board. But i can't get the device being detect.
I tested another i2c device (EEPROM) and got the device address detected. So i guess it has to be a hardware problem.
As far as i could find out:
RPi has a 1.8k pullup resistor on SDA and SLC already on board
my GY 521 also has also a pullup resistor (2.2k) on each line on board
Could the resistors be the problem? A good resistor value in sum would be around 5k on each line?
(The wiring should be ok, there are a lot of instructions around the net and i've checked it multiple times. I use 5v on the GY521 since it has a voltage converter)
Any help appreciated!
The problem was bad soldering.
For the record:
Using the RPi pullups in combination with the breakout board pullups works for me.
i have a raspberry pi connected with two ds18b20 temperature sensor.
-sensor1 is fixed on the outside of my garage (distance 20m from raspberry pi)
-sensor2 is just connected in a breadboard near the raspberry pi.
Everything is working well.
I decided to add sensor3 located outside and from 20m from the raspberry pi.
Now when i type :
cd /sys/bus/w1/devices
if find this:
c0-40a000061005 c2-246056869800 c2-247056869000 d0-008000001000 w1_bus_master1
instead of :
28-.....
28-.....
28-.....
each sensor ref should be start with 28-.....
what is happening with my sensors?
If unplugged the sensor1, then everything is well
if i unplug the sensor3 and let only sensor1 and sensor2 everything is well.
Which modification do we have to do when sensor are located far from the raspberry pi?
thank you
That means that the 3rd sensor doesn't have a 4.7kOhm or 10kOhm resistor between VCC and the OUT wire (black/red one if you have 4wire DS18B20).
Just connect that resistor and it will work , I had the same problem . I spent weeks to find such an easy solution. And if you get the same code after you connected the resistor , that means you didn't connected it properly.Hope will help you
Looking for some help to be honest, This is not my area of knoladge atall.
Ive read around the question of powering my Pi with a battery, now I nabbed one of these guys for my phone
http://www.amazon.co.uk/13000mAh-Portable-External-Technology-Motorola-Black/dp/B00BQ5KHJW/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1420826597&sr=1-1-catcorr&keywords=anker+astro+e4
Incase the link dies in the future;
Item model number: AK-79AN13K2-BA
Anker® 2nd Gen Astro E4 13000mAh 2-Port (3A Output) Fast
Max 3A Out
5V Out
Now, from what i've read there have been mixed notes of, don't use batterys, only use this battery, don't do this, don't exeed this magical number ( which was differant each time ). so any help would be grately needed. If i was to power my pi via this thing. im I going to get a poof of smoke and need to replace the poor pi :(
A raspberry Pi is powered via USB, which means that it simply takes the 5V supplied via USB to run. As long as your current source is stable (ie. it doesn't change when you draw current from it), no device will care whether it is a battery or a switching power supply. Now, a bare raspberry Pi B uses less than 2W of power, 2W/5V = 0.4A = 400mA, so if that battery pack lives up to its specification, you are going to be fine. The device is spec'ed to provide 13000mAh, so at a constant current of 400mA, this would last you more than 32 hours.
Now, most people attach something to the raspberry, and that something will also draw power, but just add that power to the calculations above, to see if it's going to work out.