Allen57
commented
4 years ago Hello, thanks a lot for all your work on this sensor so far. I've recently been toying with it and I wanted to share my own version of "debouncing" temperature and humidity in case it can be useful to someone.
Based on a given debouncing delay (120s for example), I send the temperature and humidity every 120s but I update each of the value, for temperature and humidity, only if they did not "bounced" back to their old value in the 120s delay.
I've made a dumb implementation through a callback but this could be integrated into the original script as well.
[...] --callback debounceSendToDomoticz.sh
```sh #!/bin/sh cd "$(dirname "$0")" DEBOUNCE_DELAY=120 TMP_DIR=tmp_data_$2 if [ ! -d $TMP_DIR ]; then mkdir -p $TMP_DIR touch $TMP_DIR/old_temp echo 0 > $TMP_DIR/old_temp_date touch $TMP_DIR/old_hum echo 0 > $TMP_DIR/old_hum_date echo 0 > $TMP_DIR/last_send_date fi val_temp=$3 val_hum=$4 val_date=$7 old_temp=$(cat $TMP_DIR/old_temp) if [ "$old_temp" = "$val_temp" ]; then echo "Reset temp date" echo $val_date > $TMP_DIR/old_temp_date fi old_temp_date=$(cat $TMP_DIR/old_temp_date) if [ $(($val_date - $old_temp_date)) -ge $DEBOUNCE_DELAY ]; then echo "Updating temp value" old_temp=$val_temp echo $val_temp > $TMP_DIR/old_temp echo $val_date > $TMP_DIR/old_temp_date fi old_hum=$(cat $TMP_DIR/old_hum) if [ "$old_hum" = "$val_hum" ]; then echo "Reset hum date" echo $val_date > $TMP_DIR/old_hum_date fi old_hum_date=$(cat $TMP_DIR/old_hum_date) if [ $(($val_date - $old_hum_date)) -ge $DEBOUNCE_DELAY ]; then echo "Updating hum value" old_hum=$val_hum echo $val_hum > $TMP_DIR/old_hum echo $val_date > $TMP_DIR/old_hum_date fi last_send_date=$(cat $TMP_DIR/last_send_date) if [ $(($val_date - $last_send_date)) -ge $DEBOUNCE_DELAY ]; then echo $val_date > $TMP_DIR/last_send_date echo "sending $old_temp/$old_hum" ./sendToDomoticz.sh $1 $2 $old_temp $old_hum $5 $6 fi ```The advantage for me is that I can keep the two decimal precisions and this work as well with the humidity.
It can still be improved at the bouncing detection part which only checks if we go back to the exact old value: we could also detect if we go from a higher value to a lower value (or the reverse).
(On a side note, calling a python script every 6 seconds, per sensor, was cpu intensive for my rpi so I switched it to a shell script)
JsBergbau
This is an issue with the LYWSD03MMC Sensor. On successive readings/receiving of the temperature the value bounces a lot. Therefore the debouncing switch has been implemented. It works that way: (We skip the rounding which is only used after startup until the second decimal place is not anymore within 0.2 and 0.7). Say temperature read is 11.81 degrees. Than it is rounded downwards (floor) to 11.8 If the next reading is 11.86 it is still floored to 11.8 If it reaches 11.7 it rounded up to 11.8 If the next reading is 11.83 it is still rounded up to 11.9 When the next reading is 11.82 it is floored to 11.8 When next reading is 11.85 or 11.86 it is still florred to 11.8
Due to the way debouncing works it can only be used together with --round option. If round option is not specified, but --debounce than debouncing is ignored.
I have multiple BME280 and also DS18B20 sensors. Without any measures they show a lot less bouncing values. They just give a lot more decimal places and I'm using only 2 of them. Giving quite stable values.
LYWSD03MMC gives 17 bounces in that measurement without debouncing measures within about 20 minutes
LYWSD03MMC with debouncing. Within roughly more than half an hour "only" 6 temperature bounces. The humidity is bouncing, but there is no possibility to debounce without losing precision. Things like moving average can still be down when displaying the data
--> Debouncing ok