A small and cheap bluetooth temperature and humidity transmitter

From time to time a need a small temperature (and humidity) module that sends the data with a Bluetooth connection. When I want to measure for example the temp in a frig, I can use this device. Normally I use a arduino with Bascom to develop those things but I want to put everything in an empty Frisk box, I have a small BT module and a DHS11 that fits into it (a attiny45 to runt it?) I want to power the module with a usb plug ( usb power pack) and read the data with my Nokia C0 mobile, if possible.