Nope Matty. Desu is a verb "to be". That conjugates to "am", "is", and "are.
In this case: Hello, I am a compass. The subject in the Japanese translation is "Watashi", the verb is "desu", and the object is "compass".
The verb always goes after the object in Japanese, and adjectives are considered objects in all languages.
The article "a" is assumed.