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Author Topic: Mod-Pulse MSP430FG439 (Retrieve blood oxygen percentage value)  (Read 1245 times)

rogernm001

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Mod-Pulse MSP430FG439 (Retrieve blood oxygen percentage value)
« on: September 12, 2017, 07:49:10 AM »
Hello, I am new to this device, I am hooking up the UEXT's TXD port to an arduino board via analog A0 to read serial data however when using the serial monitor I get outputs ranging from 1-4 when using the pulse-oximeter and of course when it is off my finger I get 0. I feel that these readings are incorrect because the waveform is showing a bunch of noise. How can I get accurate readings from the UEXT port?

LubOlimex

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Re: Mod-Pulse MSP430FG439 (Retrieve blood oxygen percentage value)
« Reply #1 on: September 13, 2017, 04:58:51 PM »
I think the Arduino's UART works at 5V... did you lower it to 3.3V first?

The data coming from MOD-PULSE can be visualized on PC, without the need of changing the firmware of MOD-PULSE. This, however, requires an extra serial <-> USB cable. Generally, I advice you to take a look at the files and description that we have provided for another similar connection for another product MOD-EKG. The setup to connect to a personal computer is very similar and you can use as a basis for the connection between MOD-PULSE, MOD-USB-RS232, and a personal computer. The archive is here:
https://www.olimex.com/Products/Modules/Biofeedback/MOD-EKG/resources/Connecting-MOD-EKG-to-PC-via-MOD-USB-RS232-board.zip

You need a USB-serial converter cable with proper 3.3V voltage levels at the board side. You can use either MOD-USB-RS232 or BB-CH340T or USB-SERIAL-CABLE-F.
Technical support and documentation manager at Olimex

rogernm001

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Re: Mod-Pulse MSP430FG439 (Retrieve blood oxygen percentage value)
« Reply #2 on: September 15, 2017, 07:19:13 AM »
I actually did purchase the MOD-USB-RS232 connector however I could not install the driver it seems like the computer couldn't recognize it, I have the driver to install it from a file but it says it could not be found I'm striking out here. I haven't lowered the UART however I will look into that. Thank you for your help.

LubOlimex

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Re: Mod-Pulse MSP430FG439 (Retrieve blood oxygen percentage value)
« Reply #3 on: September 15, 2017, 11:50:24 AM »
What is the operating system that you use?

The inf file seems to work fine with all version of Windows that I've used. Windows 10 even seems to find own compatible driver. Make sure to find the entry of the unit in "Windows Device Manager" and point it manually to the .inf file from this archive https://www.olimex.com/Products/Modules/Interface/MOD-USB-RS232/resources/Demo_MOD-USB-RS232.zip (in folder "inf").

Again for MOD-USB-RS232 connection remember to set the jumpers properly as described in the document that I shared in my previous post.
Technical support and documentation manager at Olimex