If so then it should be attached to /dev/sda1 – additional drives will use /dev/sdb1 and /dev/sdc1 etc. I am assuming you only have 1 external hard drive connected to the Pi. Mount External USB Hard Drive on Raspberry Pi.The transistor and capacitor provide a simple filter for the 5v input from the Raspberry Pi. On the perf board, each of the headers in a block are soldered together. Step 3 adds a perf board, which simplifies the wiring and reduces 5v noise in the FM audio. There are a lot of connecting wires in this project.
