Abstract: A colorimeter accessory for a smartphone is provided that, by leveraging the high-volume development of sophisticated smart phone technology, substantially reduces the cost of a colorimeter. The invention provides a sample holder that adapts to a range of smart phone cameras and that provides a light source and interference filter necessary for making accurate narrowband measures of light transmission through the sample holder. A correction system operates to compensate for characteristics of the smart phone camera that can affect accuracy of the reading. The processing system of the smart phone may be enlisted for this correction system and for calculation of concentrations of solution through the measurements that are made.

Abstract: A colorimeter accessory for a smartphone is provided that, by leveraging the high-volume development of sophisticated smart phone technology, substantially reduces the cost of a colorimeter. The invention provides a sample holder that adapts to a range of smart phone cameras and that provides a light source and interference filter necessary for making accurate narrowband measures of light transmission through the sample holder. A correction system operates to compensate for characteristics of the smart phone camera that can affect accuracy of the reading. The processing system of the smart phone may be enlisted for this correction system and for calculation of concentrations of solution through the measurements that are made.

Abstract: A wheel accessory, e.g., a full wheel cover or a hub cap has a mounting flange provided with openings which match the bolt pattern of the vehicle wheel. A majority of these openings are oversized with respect to the wheel's chamfered or ramped lug nuts so as to readily slip over them. The remaining openings are slightly undersized with respect to the major diameter of the chamfered lug nuts and require the removal of the corresponding lug nuts to allow mounting of the wheel accessory. The wheel accessory is held in place, in a non-interference fit, by expandable washers placed between the mounting flange and the chamfered end of the lug nuts corresponding to the undersized openings.