'Grade-school students in a northeastern Brazilian city are using uniforms embedded with locator chips that help alert parents if they're cutting classes, the city's education secretary said Thursday.

Twenty thousand students in 25 of Vitoria da Conquista's 213 public schools started using T-shirts with chips earlier this week, secretary Coriolano Moraes said by telephone. By 2013, all of the city's 43,000 public school students, aged 4 to 14, will be using the chip-embedded T-shirts, he added.

Radio frequency chips in "intelligent uniforms" let a computer know when children enter school and it sends a text message to their cell phones. Parents are also alerted if kids don't show up 20 minutes after classes begin with the following message: "Your child has still not arrived at school."'

Read more: Locator Chips Keep Track of Students in Brazil