I saw all of those bracelets for tracking your steps etc.,their components look really small and the price for such a bracelet is around 20£. I've been playing around with arduino uno and hc-06 bluetooth module(to get some code working), but I would like to find smallest components with the cheapest price(bluetooth, battery, board). I tried arduino nano too but it's still too big. I haven't tried any batteries yet, and I would like them to be rechargeable or something else but to support the bluetooth and the board for a fair amount of time.
What would you recommend ?
Make a big one!
This one is about 5 feet across
driven by 2 of my TPIC6B595 cards daisy chained together
http://www.crossroadsfencing.com/BobuinoRev17/
What are you using for a display?
I would try Gemma from Adafruit.
Super small, only 1.1" / 28mm diameter and 0.28" / 7mm thick.
Easy-to-sew or solder pads for embedding in your wearable project
Low cost enough, you can use one for every weekend project
ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROMEven though you can program GEMMA using the Arduino IDE, it's not a fully 100% Arduino-compatible. There are some things you trade off for such a small and low cost microcontroller!
GEMMA does not have a Serial port connection for debugging so the serial port monitor will not be able to send/receive data
Some computers' USB v3 ports don't recognize the GEMMAs bootloader. Simply use a USB v2 port or a USB hub in between
I won't use a display. I just need a small bluetooth,board and batteries