A novel, low cost solar tracker suitable for use in equatorial regions around the world is presented. The solar tracker is passively activated by aluminium/steel bimetallic strips and controlled by a viscous damper. Computer modelling predicts an increase in efficiency of up to 23% over fixed solar panels. Experimental testing shows excellent agreement with the computer model. In addition, further developments to the design are critically evaluated in terms of complexity and benefit. (C) 2004 Elsevier Ltd. All rights reserved.