Embedded computing technologies are not only an integral part of traditional safety- critical applications such as jet engine and automotive brake control, they are also being used to improve people's quality of life. Trinetra integrates embedded devices to let blind users enjoy cost-effective, independent shopping. The day-to-day needs of a typical blind user greatly influenced our design and evaluation of the Trinetra system. From the beginning, the user of our system also proved instrumental in helping design and tests the system