Band watch reprogrammable?

[DazzlingWhisker]

I have a very similar watch to this one:http/www.ebay.com/itm/4-0-Bluetooth-Smart-Watch-Sport-Heart-Rate-Tracker-Wristband-Bracelet-MH08-/262392638032

I wonder if you are able to connect devces like this in to your computer and then reprogram them, like change what's displayed and stuff like that. I understand that that must be very hard, you would need the source code?

 

[DazzlingWhisker]

MERGED QUESTION
Question from DazzlingWhisker : "band watch physical problem"

I have a band which is very similar to this one:

http/www.ebay.com/itm/4-0-Bluetooth-Smart-Watch-Sport-Heart-Rate-Tracker-Wristband-Bracelet-MH08-/262392638032

The problem is that I only have the watch itself, I don't have the band for it and I don't have the charger. How shall I be able to charge it without a charger? The watch do have 2 small pins which is sticking out a little bit, and I am able to connect it with a battery via copper threads, but how will I know the right voltage? The risk is that I might destroy it.

Can someone plz help me?