Hydrogen absorption isotherms are measured in a shaker mill, which allows the mechanical activation of the material. A high pressure flexible hose is attached to a SPEX 8000 M shaker mill and the mill is connected to a gas controlling device, in order to monitor and control the applied hydrogen pressure. The influence of the milling during "in situ" hydrogenation of a Mn3Ti2V alloy and the controlled hydrogen absorption by Ca to its hydride CaH2 is investigated. Pure CaH2 as the final product after the mechanical activation is identified by X-ray diffraction. For the Ca we demonstrate the measurement of pressure-composition isotherms during milling. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.