Monitor generator Battery, diesel and oil

Hello need help i want to monitor my electric generator battery, diesel level and oil pressure.

But my problem i dont know what devices do i need in this project.

Hopefully you can help or any advice on how to do this project.

I already have raspberry pi 4 installed HA.

You need to get hold of sensors that can detect the parameters you want to measure and communicate with HA.

Depending on your level of DIY expertise, you might find useful. There are lots of sensor components supported there. Diesel level can be done with ultrasonic level sensors; plenty of options for battery voltage and current. Oil pressure might be a little less generic, but oil pressure sensors have been common in cars for years, so it’d just be a question of interfacing one of those to an analogue input.

Thanks for the reply will check on this link

If the engine already has an oil pressure sensor, you can use that as input, too. Another good value to monitor would be temperature.

For an example of how existing engine sensors can be used (in this case, for the marine data protocol NMEA 2000, not HA) see the Noland RS-11.

I would connect the sensors to a separate ESP device (or more than one) using ESPHome. This will communicate with HA but you won’t need to complicate your RPi with hardware monitoring in addition to running HA.