diff --git a/PCB.md b/PCB.md
new file mode 100644
index 0000000..ad26d90
--- /dev/null
+++ b/PCB.md
@@ -0,0 +1,7 @@
+http://www.elv.de/module/community_expertenwissen/bilder_popup.aspx?id=118&bild_id=undefined
+
+http://www.elv.de/elektronikwissen/pegelwandler-fuer-spi.html
+
+https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md
+
+https://jankarres.de/2013/01/raspberry-pi-composite-fbas-einstellungen/
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