I have been using for a while an ultrasonic level monitor for my oil tank, but I was more interested on the efficiency of the heating system and also find out how much oil I was using every day.
So I went and installed a small flow meter for oil (yes you have to cut the fuel pipe): aquametro VZO 4 OEM , not cheap but it was about the only one that could work with oil/diesel and give me a good pulse output resolution at low flow rates like heating oil.
The obvious thing would have been to wire the pulse output to the RPI but a) the tank was not close enough and b) was not keen to have a direct wire link. So I bought a NorthQ NQ-9021 with the hope that I could use it as a wireless pulse counter... and it worked. Here is my poor's man schematic of the pinout connections if anyone is interested.
- NorthQ NQ-9021 Meter Opto Sensor Pinout and Connections for Dry Contact or Opto.png (17.16 KiB) Viewed 925 times
Also, one word of caution (at least for me), whenever I tried to configure the NorthQ device, it freed so I ended up using the default configuration (factory reset) and not touching anything. The rest I left it for Domoticz to convert.
PIcture below is the data coming from the NorthQ meter directly, I just did a dummy sensor to adjust the ratios to litres. As it happens, the default option for NorthQ is pretty close to litres anyway; 1kW = approx 1L