Differences

This shows you the differences between two versions of the page.

--- pi:temperature [2017/11/24 17:21] – created slack
+++ pi:temperature [2019/11/07 17:58] (current) – external edit 127.0.0.1
@@ Line 3: / Line 3: @@
 ===== 18B20 (digital) =====
-At the end of ''/boot/config.txt'':
+Wiring:
+  * Waterproof:
+    * Red: 3.3V
+    * Yellow: 4.7 k pull-up (5.1k fine) and gpio pin nominated in ''/boot/config.txt''
+    * Black: ground
+  * Kit module:
+    * 1 (labelled ''-''): ground
+    * 2: 3.3V
+    * 3 (labelled ''S''): 4.7k pull-up and signal
-  dtoverlay=w1-gpio
+Wire as many as you like in parallel.  There are limits to numbers and to wiring length, but they're not simple.
+At the end of ''/boot/config.txt'' (replace 21 with pin number):
+  dtoverlay=w1-gpio,gpiopin=21
 Save and reboot.
@@ Line 11: / Line 23: @@
   ls -l /sys/bus/w1/devices
-Grab its address (format ''28-00000xxxxxx'').  Read the temperature with
+Grab its address (format ''28-xxxxxxxxxxx'').  Read the temperature with
-  cat /sys/bus/w1/devices/28-00[address]/w1_slave
+  cat /sys/bus/w1/devices/28-[address]/w1_slave
 The numerical value after ''t='' is the temperature in thousandths of a degree C.