SPLatco Knowledge Base

BT-TTL Bluetooth adaptor

The BT-TTL5 and BT-TTL3 adds Bluetooth serial communications to your SPLat controller.

The BT-TTL5 is suitable for the green SPLat controllers, for example the CC18, MS120, HD8, HVAC26 etc.  These controllers internally run at 5V.

The BT-TTL3 is suitable for black SPLat controllers, for example the HMI430, DIN Family, etc.  These controllers internally run at 3.3V.

This instruction assumes you are using the BT-TTL5/3 to connect a SPLat controller to an Android device.

Do not rely on Bluetooth communications to maintain the safety of a system. It does not provide a secure connection.

Installation

The BT-TTL5/3 simply plugs onto the controller’s 4-pin programming connector. Note that the 4-pin female connector on the adaptor has two lugs. These are there simply to secure the connector to the adaptor board, and are not for locating the adaptor on the controller board. When you plug the adaptor onto the controller you must make sure the pins are properly aligned.

The following picture shows the BT-TTL5 on a CC18. Note the orientation of the components relative to the connector on the controller.

On the MS120 you have to gently bend the programming connector to about a 30 degree angle from the board, in order for the adaptor to fit on the connector. You won’t be able to that if you are using a SPice board on your MS120. In that case you need to make up an extension cable up to 20cm long and run the adaptor off-board. You can also use a BT-RS232 adaptor, which has mounting holes.

Communications parameters

The adaptor is factory pre-set to 38,400 baud, 8 data bits, no parity.

Password

The pairing password is simply 1234.

Radio propagation, range

The BT-TTL5/3 is Class 2 Bluetooth, which has a range of up to 10m in free air, line of sight. The “snake” pattern on the end of the board is the antenna. This needs to be kept away from any metal surfaces, and the whole unit should not be enclosed in metal.

You can maximise the range by making sure the adaptor is in an elevated position, clear of any surrounding metal. You can use up to 20cm of extension cable.