The vibrating wire (VW) technique employs a stretched wire as a magnetic field sensor. Because of the wires small diameter (~0.1mm or smaller) and because the wire can be supported from outside the magnet, this technique is very appealing for field measurements in small gap/bore undulators with small good field regions and with limited access to the tested field. In addition, in the case of elliptical undulators in which Hall probe (HP) measurements can be affected by the planar Hall effect, VW technique can be used as an independent method to verify and supplement HP measurements. Show Partial Abstract