[Raspberry Pi Pico Review] 4. Connect Pico to the temperature sensor DS18B20 to read the temperature

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[Raspberry Pi Pico Review] 4. Connect Pico to the temperature sensor DS18B20 to read the temperature [Copy link]

1. Introduction to DS18B20 temperature sensor

1. When using a single bus interface to connect to a microprocessor, only one line is needed to achieve two-way communication between the microprocessor and DS18B20 . The single bus has good economy and strong anti-interference ability, and is suitable for on-site temperature measurement in harsh environments.

2. Wide measurement temperature range and high measurement accuracy. The measurement range of DS18B20 is -55 ℃~+125 ℃; in -10~+85 ° CThe accuracy is ± 0.5 ° C .

3. No external components are required during use.

4. Support multi-point networking function. Multiple DS18B20 can be connected in parallel on a single line to achieve multi-point temperature measurement.

5. Working power supply : 3.0~5.5V . DS18B20 can also obtain power from the data line through the internal parasitic circuit. Therefore, when the timing on the data line meets certain requirements, it is not necessary to connect the external power supply, making the system structure simpler and more reliable.

6. Measurement parameters can be configured . The measurement resolution of DS18B20 can be set to 9~12 bits through the program .

7. When the polarity of the negative pressure characteristic power supply is reversed, the thermometer will not burn out due to heat, but it cannot work normally.

8. Power-off protection function DS18B20 contains EEPROM inside , which can still save the set values of resolution and alarm temperature after the system power is off.

2. Hardware Connection

Because Pico 's IO is 3.3V , the working power supply of DS18B20 is connected to 3.3V this time .

Hardware Connection:

DS18B20 pin 1 ( GND ) --- Pico pin 38 ( GND )

DS18B20 's 2nd pin ( DQ ) --- Pico 's 6th pin ( GP4 )

DS18B20 pin 3 ( VDD ) --- Pico pin 36 ( 3V3 OUT )

III. Procedure

The system comes with relevant libraries, so you can use it directly.

import machine, onewire, ds18x20, time

ds_pin = machine.Pin(4)

ds_sensor = ds18x20.DS18X20(onewire.OneWire(ds_pin))

roms = ds_sensor.scan()

print('Found DS devices: ', roms)

while True:

ds_sensor.convert_temp()

time.sleep_ms(750)

for rom in roms:

print(rom)

print(ds_sensor.read_temp(rom))

time.sleep(2)

Here is the output:

okhxyyo

Thanks for sharing~~Looking forward to the follow-up

w494143467

With the library, coding becomes so simple, just a few words!

Albert.G

I look forward to the follow-up from the OP. I’ll buy one to play with if I get the chance. I’m quite interested.

jinglixixi

Good, it’s worth referring to!