
Paul Sokolovsky developed a proof-of-concept open source firmware for common Bluetooth modules based on the CSR BlueCore4 cheapset.
“BlueCore4-Ext is a popular Bluetooth chip used in many Bluetooth modules, some priced below $10. The idea is to create Wireless Sensor/Control Network using these modules, as Bluetooth is really ubiquitous technology nowadays, so any smartphone can be used to provide user UI/control for such network.”
Read more on this project and find code links on Paul’s blog.
Via the contact form.

“cheapset”
awesome pun
Where can I get one?
DealExtreme has some listed for $6.6, $5.58 for 5+ and 5.48 for 10+. Just search for ‘bluetooth module’. I got five about a month ago and am now working on making a programmer for them out of a chipKIT Uno32.
They are currently out of them because the page is unavailable but they have the more expensive versions.
search on ebay also – mainly in the $6 area. You’ll find them if you search on HC05 or HC06
Nice idea, but it’s not really ‘firmware’ – it’s a VM application, such as customers are supposed to write.
Interesting post because I’ve just looked at this firmware over the past week or so. Not that I know enough to know what to do with this, but the idea is great. I have a couple of HC05’s and HC06’s and wanted a consistent firmware (not the linvor one which seems to me to be less flexible). I saw this post http://byron76.blogspot.com.au/2011/09/one-board-several-firmwares.html that started my exploration – all quite interesting on such a little device
Very cool. I’ve used a few of these in the past but I’ve never done anything more than change the device name and password. Only problem is I can’t think of a reason to hack them.
Except for being able to use the module’s own I/O lines; imagine, a BT operated embedded product with not other microcontroller!
Did anyone succeed in using one of the modules as a BT operated embedded board without any other micro controller ? Would relay be interested.