TTL is a rather vague term and really just means chip to chip.
It can be 5V or 3V

Also the Android Optimiser configures the BT module so if its not the same BT chipset it will require another set of initialisation commands.

Its been mentioned a number of times - https://www.sparkfun.com/products/10269

That's right. Very similar to the way the USB connector is wired now

To be honest with you no I have'nt. 

I am still a bit confused with how to wire them up, the voltage implications and the suggestion that not all BT modems will work with the MyEcu. I have'nt had the nerve to connect one up yet. If I connect one up just to power source should my Android phone 'see' it?  That would seem to the first step I will have to try to at least get it in contact with the phone before connecting it to the MyEcu, should only blow the BT module then if I get it wrong.

I have my house up for sale at the moment and am having to live extra tidily, or "like normal folk" according to my wife, so no boxes of bits and soldering irons laying around. Taking a little time to find things now as everything is in boxes to show how uncluttered the place is........

Hi, here is a short update and summary of getting an older My16M to work with BT Optimiser. This information can be found elsewhere in the forum but it is a bit scattered.

My16M used here : http://files.myopera.com/v2tre/albums/6329701/2012-10-11-1185.jpg

1. For BT communication, you need a MyECU with recent enough firmware version. If in doubt check from Cliff.

2. You also need a new enough ATMega processor chip (ATMega 324) to  match up with the newer firmware.

3. The one BT modem that is known to work ok is this one : https://www.sparkfun.com/products/10269

4. The BT modem is connected with a modified cable into the RJ45 plug on the MyECU board : http://files.myopera.com/v2tre/albums/6329701/2012-11-21-1326.jpg

The wiring of the modem is easy. Just ensure that you connect the Vcc (+5 V) and GND correctly. Then connect Tx from the MyECU to Rx at the BT modem and Rx from the MyEcu to Tx at the BT modem. Plug your new cable to the board : http://my.opera.com/v2tre/albums/showpic.dml?album=6329701&picture=171052272#big...

5. Download the Android Optimiser and install to your phone. I think the latest version is here : http://www.cajinnovations.com/MyECU/ECUController/Optimiser06b.apk

6. Power up MyECU and you see led blinking on BT Modem.

7. Pair your phone with the BT modem. It will be shown as "RN-42 something" and the pin is 1234. Please note that the name and bin in the map-file seem not anymore have any meaning. Those can be ignored. Your phone might show notification : "Paired but not connected". Led is now lighted continuously.

8. Now when the phone is paired with the modem, launch the Optimiser App. Inside the App you need to select the BT modem to make up the connection. After that you can start using the other features.

Here My16M is talking with Samsung phone over the BT : http://files.myopera.com/v2tre/albums/6329701/2012-11-21-1324.jpg

Please correct any mistakes or errors.

br, JuhaV

Thankyou JuhaV, you have encouraged me to take another look at this method of connecting to the MyEcu.

I am hoping to use a Samsung Galaxy Mini

Hi guys

Here a source of this modules in europe. Not much more expensive than direct from sparkfun, and no need to worry with customs.

http://www.hobbytronics.co.uk/wireless/bluetooth/bluesmirf-silver