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Using SleepyHead software with wearable recording pulse oximeter



PulseOx-darkThe Contec CMS 50F is an amazing bit of kit and I’m digging it.

This thing is GREAT. 82 dollars (get it HERE on Amazon), it displays and records your oxygen level and your pulse. My friend Steve calls it the “Un-fit Bit”, as in a FitBit for me to measure my poor health. lol. (And it’s more accurate than FitBits recently were alleged to be.)


The menu button (which is the only button) on the unit is not intuitive, and the Chinglish manual is hard to follow. Basically you hold the button down to access the menu, then press it once to move from each item to the next. You can only move down, not up, you have to go all the way around if you miss your item. Then hold the button down to select, then follow prompts.

You have to enable recording to record and disable recording to stop. And while recording, the unit does not display for very long. You have to choose between seeing the display and recording. But you’d likely be recording while sleeping, so not want the display on anyway. When recording, if you press the menu button, the display will come on for a moment too, then turn off. The unit will continue recording while it turns on.

You can only record one session at a time (up to 24 hours of data), but once you download and delete it, you can record another.

You can set the time in the menu (though it sets when you connect to SleepyHead, more on that below). You can set the brightness of the display also.

In the menu you can also enable sounds. They are disabled by default, and I like them that way. I don’t want an alarm waking me up if my O2 dips below 90 for a moment. I’d never get any sleep. But you may want to enable them. You can also set the low limit that determines when the alarm goes off. And you can enable a beep with each heartbeat, which is VERY annoying.

Unless you have a burning desire to hear constant noises, I’d recommend leaving the sounds off.

You charge the built-in battery in the unit, and also upload data to a computer, by connecting the included USB cord. (The unit must be on, and should not be recording, to import).

The unit is fully charged when the light on the side by the USB port turns from orange to green. There is also a USB charger that plugs into a wall if you want to leave your computer off while charging.

The oxygen percent is the big number. (95 is good, below 90 is bad.) Pulse is displayed as a smaller number to the right of the oxygen number. The pulse is also displayed as a pulsing bar on the right, and as a waveform below. The height of the waveform corresponds to the strength of the heartbeat.

When actually wearing the unit, connect the other USB device, the finger probe. The side with the light (where the wire comes out) goes on the fingernail side of your finger. Middle finger or index finger is best. Do not use on a hand receiving an IV of any kind, or using a blood pressure cuff or other medical gear. Both will reduce the accuracy. So can very bright lights directly on the probe.

Do not tape the probe to your finger. You won’t need to, it should stay on all day or night without tape. If it falls off, just put it back on.

Sometimes if you are moving and the cord connecting the finger unit gets moved, the unit will stop displaying for a moment, and will then sometimes display and/or record wildly inaccurate readings. These last only seconds, and can be ignored. The unit will quickly “catch up” and start displaying or recording accurate readings pretty quickly.

The included Windows-only software sucks, download the free SleepyHead instead.


SleepyHead was made by my friend Mark for interpreting and displaying CPAP machine data, but also has an Oxymiter import function. Get SleepyHead for Windows, Mac or Linux free here, (NOT on apnea board, that’s a pirate version that isn’t reliable).

Ignore the “Sleepyhead has shut down” notice. SleepyHead is not being devolved anymore, but works great.

Read my review of Sleepyhead here.

The device you’re importing from must be ON when importing.

And you must use the USB cable that came with your device, not a third-part one. The one that comes with the device has a “choke” that removes radio and electromagnetic interference that can prevent downloading of data:

NOTE: If, when importing, during “Scanning for compatible oximeters” it fails with the message “Could not detect any connected oximeter devices.”, you need to add the USB-to-UART driver first. (older versions are here.) Pick the correct computer operating system (later versions of Windows are way down that page.)

In SleepyHead, pick “Oxymitry Wizard”,

pick first

Then pick the top choice from the drop-down menu (CMS50Fv3.7+/H/I, Pulox PO-400/500), tick “Erase Session after Successful Upload”, and click “Import directly from a recording on a device.”

Ignore this warning:


Importing data:


Setting time:

setting time

Now you’re finished. Click “Statistics” to read imported stats:

click stats

Scroll down to Oxymiter Stats:

scroll down

Click “Daily” to see the info in time-delimited X-Y axis graphs:


If you hold down your left mouse button and drag the mouse over a section of the graph, you can expand the view for more detailed micro analysis:

dragRepeatedly right-clicking on the waveform will reset the view to macro, as will closing and re-starting SleepyHead.

Michael W. Dean

8 thoughts on “Using SleepyHead software with wearable recording pulse oximeter

  1. Thanks for writing this Tutorial. The one step I missed was installing the USB to UART driver (this is described clearly in SleepyHead’s Oximeter Import Wizard information page, but I originally missed it). The result was that “Scanning for compatible oximeters” failed with the message “Could not detect any connected oximeter devices.”

  2. MC, Thanks for your review of the CMS 50F on Amazon ..and leading me to the software. Unlike Ned (above), it linked to my iMac just fine.

    Question however: Can you extrapolate the likelihood of Apena events from the data? Sleep Apena was only a suggestion from my primary, so I did not want to enter a formal study. (and I like gadgets..)

    One interesting one is a pocket ECG called Read My Heart from DailyCafe in Tiawan. It makes a decent strip that.

    Thanks again.


  3. Thanks for writing this. I was having trouble with getting my CMS50F data to sleepy head. SO I deleted the SPO2 software and lo and behold the O2 session shows up in sleepyhead but I cannot see the 02 saturation limit or the pulse rate data like in screen shot #7. What did I do wrong?

  4. Feb 24, 2016
    I have Sleep Apnea. So I need to find out the number of sleep apnea events per hour after an overnight sleep study. It is also called Desaturation Index.
    For mild sleep apnea (Index 30).
    How do I get these numbers after an overnight sleep study?
    a. Number of events/hr
    b. Desaturation Index

    I have already ordered (not received yet) Wrist Pulse Oximeter
    Model # CMS 50F from Copper Medical
    Do you think I can use this unit with SleepHead software?
    Please reply soon. I live in Vancouver, Canada.

  5. Well, the software works great with my Bipap. However, I bought the Pulse Oximeter described above. I used it last night. Everything looked fine and I turned on the recording and recorded 7 hours of sleep. I downloaded by Bipap SD card first and then connected the oximeter to my Mac. I got a light on the oximeter showing it connected and I am able to scroll through all the files using Finder. However, when I follow your directions above, the Wizard scans for my oximeter and then tells me that it was unable to detect any connected oximeter devices. So, I’m assuming I got one that doesn’t work so well. Also, I will say that I held my breath for 30 seconds and the pulse oximeter continued to show me being at 97. So, it’s a $89 investment that I will be sending back to Amazon for a refund. Good review above, but this oximeter product seems to have some issues. I will continue searching for a oximeter that works with Macs.

    1. “I held my breath for 30 seconds and the pulse oximeter continued to show me being at 97….”

      You know it takes about 90 seconds for O2 (or lack of 02) in your lungs to go through your body, right?

      I took this oximeter with me to a doctor’s appointment. It is consistent with the higher end gear my pulmonologist has.


  6. Thanks for creating this software for Macs. I now can buy the CMS-50F wrist pulse oximeter. I also was able to look at my bipap data too to confirm the software’s ability to work on my Mac. cool!

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