Maybe not quite what you are looking for, but may still be of some use: <a href="http://www.conti-online.com/www/industrial_sensors_de_en/" rel="nofollow">http://www.conti-online.com/www/industrial_sensors_de_en/</a>
what is "affordable" to you?<p>what range, wavelength (or: visible/invisible), opening angle, moving/stationary, indoor/outdoor, sunlight resistant, what target materials etc.<p>provide some context if you want a good answer