Curious about what was encoded in the barcode of my student ID card and lacking a bar code scanner, I read the code off the card by eye and wrote a quick hack to decode it. It takes a sequence of 'n' and 'w' (for narrow and wide).

Code39 consists of narrow and wide bars /and/ spaces. (The spaces are just as significant as the bars). Each character is five bars and four spaces, meaning every character begins and ends with a bar (there is a narrow space in between each character). Each code starts and ends with a '*' (nwnnwnwnn).