diff --git a/docs/src/setup/seatalk/seatalk.md b/docs/src/setup/seatalk/seatalk.md index 00d5c249f..9b1c1a5ff 100644 --- a/docs/src/setup/seatalk/seatalk.md +++ b/docs/src/setup/seatalk/seatalk.md @@ -10,11 +10,15 @@ _Inspired by [Read SeaTalk1 from the Raspberry Pi GPIO using pigpio](https://git ### Hardware -![ST1_opto_SK](./seatalk_circuit_1.jpg) - Using an optocoupler as the hardware interface is recommended as it creates electrical isolation from hazardous voltages and avoids ground loops. -The circuit above uses the [PC817 optocoupler](https://www.amazon.com/ARCELI-Optocoupler-Isolation-Converter-Photoelectric/dp/B07M78S8LB/ref=sr_1_2?dchild=1&keywords=pc817+optocoupler&qid=1593516071&sr=8-2) but any equivlent product can be used. The LED in the circuit will flicker when there is ST1 traffic. +The circuit below uses the [PC817 optocoupler board](https://www.amazon.com/ARCELI-Optocoupler-Isolation-Converter-Photoelectric/dp/B07M78S8LB/ref=sr_1_2?dchild=1&keywords=pc817+optocoupler&qid=1593516071&sr=8-2) but any equivlent product can be used. The LED in the circuit will flicker when there is ST1 traffic. + +![ST1_opto_SK](./seatalk_circuit_3.jpg) + +If you are building the interface yourself use the below circuit instead. If you don't want any flickering just drop the LED at the input. + +![ST1_opto_SK](./seatalk_circuit_4.jpg) A simpler, non-electrically isolated, solution is detailed below, using a low signal NPN transistor which inverts and shifts the voltage from 12V DC to 3.3V DC. @@ -70,8 +74,7 @@ _Example Data Connection:_ ![GPIO](./gpio.png) -- Set _Invert Signal_ based on the hardware interface you have used _(e.g. Select **Yes** if using the hardware setup above. Select **No** if using a hardware interface that does not invert the ST1 signal)_. - +- Set _Invert Signal_ based on the hardware interface you have used _(e.g. Select **No** if using the optocoupler hardware setup above. Select **Yes** if using a hardware interface that inverts the ST1 signal)_. - Click **Apply** to save your data connection settings.