vanommen.rob...@gmail.com wrote: > Indeed this is code what I found on the web to read temperatures from 10 > DS18B20 singlewire sensors. > > My only programming (little) experience is VBA (Excel mostly). > > avgtemperatures = [] is indeed from the original code where this line > > 'avgtemperatures.append(sum(temperatures) / float(len(temperatures)))' > > was added. i removed it. > > You're right about the line sensorids. There are 10 sensors: > > sensorids = ["28-0000054c4932", "28-0000054c9454", "28-0000054c9fca", > "28-0000054c4401", "28-0000054dab99", "28-0000054cf9b4", > "28-0000054c8a03", "28-0000054d6780", $00054ccdfa", "28-0000054c4f9d"] > > > In this script i want to read the temperatures and make them available to > other scripts. > > One script to controll my solar water boiler and other heat exchangers > connected to this boiler. (fire place for example) And in the future I > want to make the temperatures available on a website and log them in a > mysql database online. > > But as I said before, I am just a few days trying to learn how to do it. > > Thanks for your time. > > greetings Robert
(Warning: all untested code -- I don't have a Raspberry Pi) When you use constants as sensor ids your code will only work for one machine, with one configuration. I recommend that you read the sensor ids once at startup of the script and then operate with these. For the code poste below I assume that the output of the sensors looks like the examples on this page: http://www.gtkdb.de/index_7_2035.html Namely the list of sensors... pi@raspberrypi ~ $ cat /sys/devices/w1_bus_master1/w1_master_slaves 10-000801e1799b 10-000801e17146 10-000801e17bc6 and the state of a single sensor: pi@raspberrypi ~ $ cat /sys/devices/w1_bus_master1/10-000801e1799b/w1_slave 2d 00 4b 46 ff ff 02 10 19 : crc=19 YES 2d 00 4b 46 ff ff 02 10 19 t=22625 You can then deal with the "lowlevel" stuff in a module like the following... $ cat sensors.py def read_sensorids(): with open("/sys/devices/w1_bus_master1/w1_master_slaves") as f: return [line.strip() for line in f] def read_sensor(sensorid): with open("/sys/bus/w1/devices/{}/w1_slave".format(sensorid)) as f: temperature = f.read().rpartition("=")[-1] return float(temperature) / 1000.0 def read_sensors(sensorids=None): if sensorids is None: sensorids = read_sensorids() temperatures = {} for sensorid in sensorids: temperatures[sensorid] = read_sensor(sensorid) return temperatures def print_temperatures(sensorids=None): for k, v in read_sensors(sensorids).items(): print("Sensor {}: {}".format(k, v)) ... and use it like so: $ cat sensors_demo.py import sensors import time def demo1(): print "Demo1: detect sensors and print temperatures" print "current temperatures:" sensors.print_temperatures() print def demo2(): print "Demo 2, detect available sensors" print "found the following sensors:" for sensor in sensors.read_sensorids(): print sensor print def demo3(): print "Demo 3, choose a sensor and read its temperature every second" print "found the following sensors:" sensorids = sensors.read_sensorids() for index, sensor in enumerate(sensorids): print " {}: {}".format(index, sensor) index = int(raw_input("Choose an index ")) follow_sensor = sensorids[index] print "following", follow_sensor while True: print sensors.read_sensor(follow_sensor) time.sleep(1) if __name__ == "__main__": demo1() demo2() demo3() A (simulated, as you might guess from the odd variations in temperature) run of the above: $ python sensors_demo.py Demo1: detect sensors and print temperatures current temperatures: Sensor 10-000801e1799b: 45.052 Sensor 10-000801e17146: 23.841 Sensor 10-000801e17bc6: 45.5 Demo 2, detect available sensors found the following sensors: 10-000801e1799b 10-000801e17146 10-000801e17bc6 Demo 3, choose a sensor and read its temperature every second found the following sensors: 0: 10-000801e1799b 1: 10-000801e17146 2: 10-000801e17bc6 Choose an index 1 following 10-000801e17146 12.744 39.557 17.345 16.49 49.73 27.925 35.007 44.142 37.187 10.261 44.359 ^CTraceback (most recent call last): File "sensors_demo.py", line 36, in <module> demo3() File "sensors_demo.py", line 30, in demo3 time.sleep(1) KeyboardInterrupt Again, as I don't have a machine to test the above some of my assumptions may be false -- or worse, true nine times out of ten. -- https://mail.python.org/mailman/listinfo/python-list
