Wireless monitoring battery status

Don’t know if this can be made, on amature level.

I want to measure status of a battery . So when the battery is going below ex 18v it’s sending a signal to a dc motor To start to open a door.

And this battery sensor need to Be wireless, and using a battery to power it. Or if I can change the output on the 18v battery to run it.

I hope this make any sensex if not let me know and I will try again:)

Regard

It is possible. Normally, for such a task, you don't want the efforts to measure the voltage causing a significant current drain.

  1. You can use a voltage divider to drop the source voltage to, say, the 5 volt range, so it can be measured with an arduino. A voltage divider is not, however, appropriate for providing power to an arduino.

  2. You do not want a voltage divider to be across the source permanently, because it drains energy. Therefore you would switch it with a mosfet at the time you wanted to make the measurement.

  3. You could power an arduino and radio module with a 3 volt battery. For minimum power, the arduino would wake up periodically, switch the voltage divider, test the voltage, power up the radio and send the information to the receiver, then sleep for the remainder of the cycle.

I have published a project here https://forum.arduino.cc/index.php?topic=693007.0 which, as part of its function as a mailbox notifier, wakes up periodically, and sends voltage information to the receiver. It is also optimised for very low power consumption. Maybe you find something you can use there.

6v6gt:
It is possible. Normally, for such a task, you don’t want the efforts to measure the voltage causing a significant current drain.

  1. You can use a voltage divider to drop the source voltage to, say, the 5 volt range, so it can be measured with an arduino. A voltage divider is not, however, appropriate for providing power to an arduino.

  2. You do not want a voltage divider to be across the source permanently, because it drains energy. Therefore you would switch it with a mosfet at the time you wanted to make the measurement.

  3. You could power an arduino and radio module with a 3 volt battery. For minimum power, the arduino would wake up periodically, switch the voltage divider, test the voltage, power up the radio and send the information to the receiver, then sleep for the remainder of the cycle.

I have published a project here https://forum.arduino.cc/index.php?topic=693007.0 which, as part of its function as a mailbox notifier, wakes up periodically, and sends voltage information to the receiver. It is also optimised for very low power consumption. Maybe you find something you can use there.

Thanks

I idee is to connecet to my automower so when the batteri is low, and it need to recharge, let say 15V it will send a signal to the door to open. I am new to arudion, and ESP and what namne it all have:S hehe i want to learn, but is hard

regard

That is then quite an ambitious project. It sounds like you have already chosen some hardware since you have mentioned ESP. Start by learning about the capabilities of the ESP (ESP8266 or ESP32?) and do some basic tests following a tutorial. Hint: it maybe that the ESPNOW library may be appropriate for this since it looks like a peer to peer application.