With the advent of low-priced Bluetooth modules, it is now possible to connect to the ECM with EcmSpy wirelessly. Using this method, the cable is no longer needed, being replaced by a small Bluetooth adapter at the DataLink connector and the Bluetooth capability of the laptop. Unfortunately some of the cofiguration is not supported of PalmOS, therefore the PDA will still be cable-bound.
The installation of a Bluetooth module is quite simple, especially since models are offered with a serial interface at TTL voltage level, which are necessary for connectionn to the ECM. Unfortunately the voltage supply at the DataLink connector is too high for these modules at 12V, but with a voltage regulator (e.g. a IC 78L08) the necessary supply voltage is easily available. The bluetooth modem itself is equipped with a 5 volts voltage convertor, so an "intermediate" power of 8 Volts seems fine. This will protect the modem's built-in convertor from over-voltage. The Bluetooth module voltage adaptor shown is the size of a postage stamp. (Clicking on a picture opens it in a new window.)
Click picture for an unscaled view
The Bluetooth module is no bigger than a USB plug, the module shown here is a "BlueSMiRF" sold by Sparkfun electronics however there are other suppliers selling similar solutions.
Click picture for an unscaled view
The Bluetooth unit now consists of the Bluetooth module, some veroboard and a voltage reulator. The red wire linking the tracks links CTS and RTS as for this implementation no flow control is required. (Some bluetooth modems need only a drop of solder applied to a small pad to connect these two lines.)
The Deutsch connector is then added to allow connection to the diagnostic socket of the ECM. In this picture the following wiring scheme is used:
At this point, it is better not to put the module in a box or housing, to enable the light emitting diodes to be seen.
Click picture for an unscaled view
I decided against using a box, but heatshrinked the wireless modem into some clear shrinkable tubing to provide some protection. This material is meant for building battery packs and hardens after cooling.
Click picture for an unscaled view
To make the Bluetooth dongle working and to commission the adapter, the Bluetooth driver software must be installed according to the manufacturer's instructions. The PC or Laptop can then search for and connect to the Bluetooth module. To set up the wirespeed the Bluetooth modem uses to talk to the ECM, disconnect the modem from your PC, remove power from the modem and power it up again. While the red LED is blinking rapidly, connnect to the modem using any terminal emulation (Hyperterminal, TeraTerm, LynxTerm ...) and enter three "$" characters. The modem will respond with a "CMD" output and is set to command mode now. Now you can change the wire speed to the 9600 baud required by the ECM as shown below. The modem will not echo any input, so you have to type all commands blindly, followed by "return":
| Set to 9600 baud wire speed | ||
|---|---|---|
| Command | Request (sent) | Response (received) |
| Enter configuration mode | $$$ | CMD |
| Display setup | d | ***Settings*** BTA=000666019880 BTName=FireFly-9880 Parity=None Mode =Slav Authen=0 Encryp=0 PinCod=1234 Bonded=0 Rem=NONE SET |
| Set baudrate to 9600 baud | su,96 | AOK |
| Display setup | d | ***Settings*** BTA=000666019880 BTName=FireFly-9880 Parity=None Mode =Slav Authen=0 Encryp=0 PinCod=1234 Bonded=0 Rem=NONE SET |
| Reboot device | r,1 | Reboot! |