Children used to hide their diaries from prying parental eyes by shutting them with a flimsy lock and stuffing them under a pillow. But, this being 2013, journals are more likely to be kept digitally, and good luck stuffing that iPad under your pillow. iHeart Locket is an iPad based diary for children which can be locked using an accompanying smart necklace pendant.

Aimed squarely at the young girl market, the iHeart Locket app uses plenty of pink and the gold smart pendant is heart-shaped. Featuring a scrapbook-style design, users can add photos, illustrations, digital stickers and audio recordings to their diary. It also features an automatic transcription function (powered by Nuance Communications) for those who are too young to type.

But, the interesting aspect of the app is undoubtedly how it works with the smart necklace pendant. A golden heart-shaped affair, the pendant sits on a purple satin ribbon and features two buttons along with a speaker which is used to play unique audio control codes.

Pressing the lock button (unsurprisingly) locks and unlocks the diary with an audio code, while the pen button makes drawings and notes disappear from the diary pages. Each pendant emits its own code, and one pendant cannot be used to open a diary created with another.

However, in case the pendant gets lost or damaged, there's the option to open a diary using a four digit backup code. Pages from the diary can also be saved to the iPad photos folder as images, or exported to iBooks as a password protected PDF file.

The iHeart Locket app is available from the App Store and is free to download. The smart necklace costs US$25.

Product page: iHeart Locket