I developed a hybrid mobile app for my own use but later I released it for others too. It will track the battery of the phone and will auto sms to someone if the charge falls below 5%. It is a very simple app which used cordova plugins to read the battery charge. Due to Google's policy changes, the app is discontinued.
I am not doing freelancing anymore. It was a great ride but I have joined a company as Chief Technology Officer (CTO).