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README.md

@@ -44,7 +44,7 @@ The P line can be used for power supply. You can also skip the part and power th
   * Wemos S2 Mini (based on ESP32-S2, does not have led) [Buy on Amazon (partner link)](https://amzn.to/3nkMbRq) / [Buy on aliexpress (partner link)](https://s.click.aliexpress.com/e/_Dnoy8df)
   * Wemos S3 Mini (based on ESP32-S3, does have RGB led)
 * 1x ULN2003A (to send commands to the bus) [Buy on Amazon (partner link)](https://amzn.to/48Qoq6i)
-* 1x Traco TSR1 2405 (dc/dc 24V to 5V as power supply for Wemos)
+* 1x Traco TSR1 2405 (dc/dc 24V to 5V as power supply for the controller to power it from the door bell system) [Buy on Amazon (partner link)](https://amzn.to/49iwwUZ)
 * 1x tripple screw terminal (to connect to the bus) [Buy on Amazon (partner link)](https://amzn.to/3OrmcSC)
 * 2x double screw terminal (optional, to connect switch and led) [Buy on Amazon (partner link)](https://amzn.to/3OrmcSC)
 * 1x 1 MOhm resistor