IRgaskiT Application Note 2

Things to do With your IRgaskiT No.2

With just a few readily available components you can make your IRgaskiT a wireless device to use with any Bluetooth enabled PC.

First you will need an IRgaskit with a suitable sensor head you will also need an RS232 Bluetooth adapter (we used the LM Technologies LM-058 see http://www.lm-technologies.com/ci/index.php?/products/details/3 ) some ribbon cable, a 9 way D type IDC socket and two micromatch plugs one (4 way one 10 way). We used a 10 way ribbon cable and a free plug (ours were from Farnell Part No. 149032, 149081 and 1555549). 

In order to make the Serial adapter cable for the LM-058 you will need to cut a 10 cm piece of ribbon cable and remove ~1cm of conductor #10 from one end. Attach the 9 way ‘D’ socket to the 9 way end of the ribbon cable (wire#1 to pin #1). Attach the 10 way micromatch plug to the ribbon cable (pin#1 to wire #1) ~5 cm from  ‘D’ type socket. Separate wires 1 to 6 from wires 7 to 10 and fit the 4 way micromatch plug to wires 6 to 10 (wire #10 to pin#1) near the end of the cable wires 1 to 6 are then removed near the 10 way micromatch. Wires # 10, 9 and 7 are removed between the 10 and 4 way micromatch plugs to leave only wire #8. Wire 8 is connected to CN5 pin 2 on the interface board to provide 5V to pin 9 (wire#8) on the ‘D’ type.  To power the LM-058 for other adapters the power may have to be provided in another way.

Figure 1 Wiring Diagram for our USB Cable

Once you have checked your cable the 10 way micromatch is plugged into CN3 and the 4 way micromatch is plugged into CN5 on the IRgaskiT interface board.

Before it can be used the LM-058 must be set up to use 57600 Bits per second, 8 Data bits, No Parity, 1 Stop bit and Software Flow Control. This is done by connecting the LM-058 to a PC and then using either the supplied utility (MS Windows) or a serial terminal to send the required commands to the LM-058.  Serial terminal emulators are available for most Operating Systems (OS) there are often supplied with the OS or are downloadable from the internet. e.g. Minicom or Gtkterm for Linux and Quickterm for OS X.

Once the setup is complete the LM-058 is set to DCE mode using the switch on the side and connected to the 9 way ‘D’ type on the IRgaskiT interface cable. When power is supplied to the IRgaskit the LM-058 will be powered through the interface cable.

 A Bluetooth enabled PC and either serial terminal software (such as HyperTerminal supplied with MS Windows up to XP but not with Vista) or the IRgaskit (MS Windows) data logger available from the Edinburgh Instruments web site may be used to communicate with your IRgaskiT via Bluetooth without the need for any cables between the IRgaskiT and the PC.

 Figure 2 below shows our USB interface cable connected to an IRgaskiT with a 10% CO2 head.

Figure 2