Hands-on: Scosche’s New Rhythm 24 Optical HR Sensor Swiss-Army Knife


I initially thought of just titling this post “Scosche’s New Rhythm 24 Optical HR Band”, but in reality, that doesn’t begin to capture what they’re doing with the new Rhythm 24.  Because almost everything they’ve added is about things beyond the optical HR sensor.  They’ve jammed NFC in there, onboard memory, cycling cadence, swimming support, tripled the battery and much more.

No doubt, the original Scosche Rhythm+ has been mind-bogglingly popular because of is incredible accuracy, as well as being cross-platform with dual ANT+/Bluetooth Smart.  It’s the optical HR sensor band that you can put up against virtually anything and come away winning the accuracy war every time.  But it was also getting a bit long in the tooth.  The battery life was a downer, at only 6-10 hours depending on how old your unit was, and it lacked some of the newer functions found in other optical HR sensors – like storage.

All of which Scosche aims to change with the new Rhythm 24.  Note that while this unit is being announced today (and you can also place pre-orders now), it won’t be shipping till later this spring (late April).  So keep that in mind for any purchasing decisions.

Also note, that this isn’t a review.  I’ve had a prototype/beta/something unit in my hands for about 72 hours, barely enough time for a few workouts squeezed in between the jam-packed CES schedule. Further, given it’s early beta, a bunch of pieces aren’t yet complete.  Note that as usual, when I’m done with this loaner beta unit I’ll send it back like normal and go out and get my own through normal retail channels.  You can help support the site here by hitting up some of links at the bottom of the post.

Now before we go too far, here’s a hands-on video that summarizes it all (note, it’s currently uploading/process, so it’ll automatically switch over within 15-20 minutes likely)!

With that, let’s dive into it!

What’s new:


It’s funny, these days we expect a heart rate sensor to do so much more than just be a heart rate sensor.  Sure, we want it accurate, but we also assume it’ll have other features.  Be it storage for saving a workout when a watch isn’t nearby to capture the data, or perhaps the ability to track running cadence/pace.  Maybe even to have LED’s to show you heart rate zones, or to track aspects while swimming.  All are things we’ve come to expect.

It’s somewhat ironic that despite lacking all those things originally, the previous Rhythm+ did enormously well because of the accuracy pieces.  Thus proving that in some cases, accuracy wins all.

With the Rhythm 24, Scosche is going back to the same optical sensor well, and using the same provider – Valencell for the optical HR sensor.  That worked out pretty well for them last time, so no reason to change what’s not broken.  Though, it’s now a new sensor.  Valencell rightly pointed out that the previous sensor in the Rhythm+ is from 2012 (!), whereas the sensor in the Rhythm 24 is now their latest gen.  They noted that “since then we’ve upgraded the MCU for lower power consumption, upgraded the LED’s in the sensor, made countless improvements to the signal processing algorithms, and made the firmware field upgradable for future enhancements”.


Previously though that limited them to about 6-10 hours of battery life, whereas now with the Rhythm 24 they’ve got 24 hours of battery life (in 1-second broadcasting/recording mode).  Scosche notes that the 24 hours is really more of a ‘minimum bar’ for them than the glass ceiling.  They’ve got more work they want to do both in terms of improvements to battery life (since they aren’t quite yet at that portion of the development phase), as well as giving users options around tweaking some of the settings for different scenarios.  Still, part of the improvement in battery life comes from Valencell and their more updated sensor.

Atop of that, there’s LED lights to now see battery status, something you didn’t previously have (aside from telling you it was dead):


The LED’s can also be used to show HR zones, which are configured through the app. At present, there’s no customization of the actual HR zones (it just uses a template), but it sounds like perhaps by shipping that’ll work out.

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Then there’s the move to two buttons.  One larger button for powering it on, and another multi-mode button for changing sports, turning on recording, and other functions.  Unlike the previous generation Rhythm+, these thankfully don’t turn on so easily accidentally.

DSC_8339 DSC_8338

Here’s a super quick look at the button guide:


Next, the unit contains on-board memory. This allows it to store data even when a watch not be around.  This can be useful for sports where watches aren’t often permitted (like soccer/football), or even in other cases, like swimming where someone may not want a chest strap or may find an optical HR sensor on the wrist less accurate.  But here’s the nifty trick: The unit will adhere to the ANT+ FIT file transfer standard, which means that your existing Garmin watch can actually download the data after the fact.


A little known fact is that when Garmin’s swim-friendly watches download data from their swimming HR straps (HRM-TRI/HRM-SWIM), they actually do so over common standards.  Any vendor can support this nearly decade old standard for transferring the HR data over.  So Scosche is doing that.  And thus, you’d be able to take something like a FR920XT, wear the Scosche 24 during a swim, and it’ll properly ask to download from that strap after the swim (assuming the planets align as planned).  At this point in the beta though, that feature isn’t yet implemented on the Rhythm 24.

For these and many other pieces, Scosche is working with NPE (North Pole Engineering) on the protocol side.  They’re known in the industry as one of the deepest groups on ANT+/BLE.  They develop the NPE WASP and NPE CABLE that many companies in the sports tech industry use for their own testing.  Thus, they know many of the ‘special quirks’ that exist in the industry in making this kind of stuff look seamless to users.  I’m personally pretty excited about that.

Speaking of standards, the unit also transmits out on the following standards:

ANT+ Heart Rate: Obviously
ANT+ Running Stride & Cadence: To pair to a watch as a ‘footpod’, or to pair to Zwift
ANT+ Cycling Cadence: To pair to a bike computer as a cycling cadence sensor
Bluetooth Smart Heart Rate: Again, obviously
Bluetooth Smart Running Speed/Cadence: Same as ANT+, just Bluetooth Smart
Bluetooth Smart Cycling Cadence: Also same as ANT+, just Bluetooth Smart

In addition, the unit will transmit heart rate variability information, though, that’s primarily designed to be used at rest and not in a workout.  It’s a mode you can toggle within the app settings.  Next, during swimming, the unit changes the algorithm a bit, enabling better accuracy.  It doesn’t record things like stroke, distance, or pace.  But instead, the mode toggle is all about telling the algorithm that what you’re doing isn’t likely running.

As part of the workout storage, the mobile app will allow you to download those workouts after the fact.  It supports swimming, cycling, running, and gym modes, as well as triathlon modes.  In the triathlon mode you’ll use that smaller button to switch between the sports, and the colored LED’s will ensure that you’ve got yourself in the correct sport.

2018-01-09 06.38.17 2018-01-09 06.38.03

Next, the unit includes NFC A-Tag.  What’s A-Tag you ask? No, it’s not part of the A-Team (though, I suppose that might be debatable).  Instead, it’s targeted primarily at gyms and such to allow the unit to interact with various gym equipment pieces, like a treadmill or other machinery.  So this is different from regular NFC used for contactless payments.  Not same-same.  This isn’t really something aimed at you to use in your home, but really for larger gyms.

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Finally and for lack of anywhere else to plop it, the unit is IP68 waterproofed, which means that it’s waterproof for immersion up to 1 meter – which is totally fine for swimming. And the strap? Re-designed to use little snap modules that are impossible to accidentally pull off when worn (due to the locking mechanism), but easy to remove when not worn.  This also should resolve the issue of the Velcro getting caught on everything.


Last but not least, the price for the new Scosche 24 is $99, versus the $79 for the previous models.  This is a bit pricier than Wahoo’s new TICKR FIT or Polar OH-1 ($79), but simply put it contains more features than those (see table down below).

First Run:

So let’s take this thing out for a run, shall we?  On today’s run I went all-in on new optical sensors, or just new sensors in general.  I had of course the Rhythm 24 on me (upper left arm), then the new Wahoo TICKR FIT (lower left arm), then Polar OH-1 (upper right arm), and finally a Wahoo TICKR-X on my chest.  And from a watch standpoint I had the Garmin FR645 (right wrist), then the a Suunto Spartan Trainer (left wrist).  And, sitting atop a treadmill to help record some of the HR data I also had a FR620 (connected to the TICKR FIT), another Suunto Spartan Trainer (connected to TICKR-X), Descent MK-1 (connected to Polar OH-1), and a FR935 (connected to Scosche). Holy balls!  That gives me the following HR data streams:

1) Scosche 24: Upper left arm
2) Wahoo TICKR FIT: Lower left arm
3) Polar OH-1: Upper right arm
4) Wahoo TICKR-X: Chest strap
5) Garmin FR645 Optical HR Sensor: Left wrist
6) Suunto Spartan trainer Optical HR Sensor: Right wrist

Please note that despite how many devices I have on, I’m actually super careful to have them heavily separated to not have them interfere with each other from a HR standpoint.  That can happen if you have two watches next to each other on the same wrist.  One will restrict blood flow a bit to the next, dorking with accuracy.  The excessive number of watches are because it’s easier for me to normalize and then analyze data coming off a watch than saved files from each HR sensor.  In fact, the data from this run is actually a treadmill run, so I just set all of the ‘collecting’ watches on the treadmill.

Oh – and wait – don’t forget that the Scosche Rhythm 24 as well as Garmin FR645 are both in beta.  The Scosche more early beta, the FR645 more late beta.  As such things may get better or worse before they start shipping.

In any case, here’s the resulting look at the run, overlaid atop each other:


Now, as with the best laid plans, sometimes things don’t work out.  And in this case, that’s the HR data from the Wahoo TICKR-X chest strap, which was totally wonky (like drunk person wonky).  So, I excluded that.  I think my strap is dying.

From a workout structure standpoint, there was a 10 minute warm-up, a quick couple minute build, and then 4×2:30 at 6:00/mile, followed by 5x45s at 5:00/mile (the fastest the hotel treadmill would go).  In between for recovery it was simply walking.

What you see left above is actually four data sources, though with smart recording on two of the watches it’s hard to find a data point that shows all four signals.  Either way, to be honest the only thing that you need to know visually is that the maroon line is the FR645 optical.  The rest are virtually all identical.

The slight differences you see with the Polar OH-1 are actually *correct* on three out of the four sprints, which is a great example of ensuring you know what the data should look like.  See, at the end those are roughly 45 second sprints.  And the OH-1 is the fastest to capture my HR declining after I stop running.  We’re only talking by a couple of seconds, but I thought it was interesting.

As for the OH-1, it nailed everything here compared to the others.  Things look really really clean.  Obviously, this is only one run, but it’s actually kinda a tough one to get right with the fast changes in pace – and so far so good!

Product Comparison:


I’ve added the Scosche Rhythm 24 into the product comparison database for heart rate sensors.  This allows you (and me) to generate comparison charts like the one below.  For the purposes of this post, I’ve compared it against two other optical HR sensor bands – the Polar OH-1 and Wahoo TICKR FIT.  I’ve excluded Mio since they announced this past fall they’re getting out of the hardware game.  But you can mix and match against any HR sensors in the database here.

With that, here’s how things stack up:

Function/Feature Polar OH1 Wahoo TICKR FIT
Copyright DC Rainmaker – Updated January 9th, 2018 @ 9:48 amNew Window Back to less results
Price $79 $79
Product Announce Date Aug 30th, 2017 Jan 3rd, 2018
Product Availability Date Late Sept 2017 Jan 3rd, 2018
Measurement Type Optical HR Optical
Typical Placement Upper Arm Mid/Upper Arm
Battery Life 10 hours 30 hours
Battery Type USB Rechargeable USB rechargeable
NFC Capable No No
HR Transmission Polar OH1 Wahoo TICKR FIT
ANT+ No Yes
Bluetooth Smart Yes Yes
Dual concurrent ANT+/BLE No Yes
Analog for gym equipment No No
Usable HR data underwater No Depends: If on same wrist, YMMV.
Bridging ANT+ to Bluetooth Smart No No
Can record activity w/o 2nd device Yes No
Additional Data Polar OH1 Wahoo TICKR FIT
Run Pace No No
Run Cadence No No
Run Economy/Metrics No No
Cycling Power Meter Estimation No No
Valid HRV/RR data No No
Configurable Sport Modes No No
Requires Bluetooth Smart Phone for Configuration No No
Firmware Updateable Yes Yes
Amazon Link Link Link
Clever Training Link (Save 10% with DCR10BTF) Link Link
Clever Training Europe (Save 10% with DCR10BTF) Link N/A
More Info Link Link
Function/Feature Polar OH1 Wahoo TICKR FIT
Copyright DC Rainmaker – Updated January 9th, 2018 @ 9:48 amNew Window Expand table for more results
Product Announce Date Aug 30th, 2017 Jan 3rd, 2018
Product Availability Date Late Sept 2017 Jan 3rd, 2018
Measurement Type Optical HR Optical
Typical Placement Upper Arm Mid/Upper Arm
Battery Life 10 hours 30 hours
Battery Type USB Rechargeable USB rechargeable
ANT+ No Yes
Dual concurrent ANT+/BLE No Yes
Usable HR data underwater No Depends: If on same wrist, YMMV.
Can record activity w/o 2nd device Yes No

And don’t forget, you and mix and match any HR sensors against each other within the product comparison database here.



Overall, I think Scosche is well positioned here with the new Rhythm 24 strap.  Yes, it’s a tiny bit more expensive than the previous one, but as long as they maintain the same high degree of accuracy as the Rhythm+ has had, then I suspect they’ll continue to attract buyers, especially once you combine all the features found on the new unit.  This might be even more so the case with the ability to offload swimming HR data, sans-chest strap.  Using a chest strap for swimming is often fraught with issues (as is an optical HR sensor on your wrist).  So this could be a solution for a bunch of folks.

I’m also looking forward to seeing where they go beyond the stated specs.  With hints to areas like sleep and beyond, as well as extension of the battery life above 24 hours, they might be looking to leverage the HRV pieces in new and interesting ways not previously seen on a standalone HR sensor in the consumer realm here (most efforts are tied specifically to watches).

Still, it’s about four months away from when this will ship – so that’s still a long time for many people.  If you’re in the market for a unit now, it’s probably going to be hard to wait, especially if there’s any slippage in the schedule (I think they’re probably good on that actually).  Of course, for a company like Scosche, announcing at CES is the right move as it’ll afford them fitness media coverage they probably would have gotten elsewhere with a standalone announcement.  Hence why they likely announced now, rather than closer.

With that – stay tuned for my full in-depth review once it starts shipping.  But since I have two beta devices, I’ll likely use them longer term over the next few months.  Much of the sensor pieces are complete based on Valencell’s existing work, whereas the time in the schedule is mostly around app integration and the non-sensor pieces (I.e workout transfer, etc…).

Thanks for reading!

Note: You can now pre-order the Scosche Rhythm 24, which is currently slated to deliver in late April.  If you order via Clever Training, then you’ll note only save 10% using DCR Coupon Code DCR10BTF, but also get free US shipping and it helps support the site here – I appreciate it!

Source: dcrainmaker

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