4iiii’s debuts Viiiiva Bluetooth Smart and ANT+ Consolidator Heart Rate Strap


Today at Interbike, 4iiii’s quietly showed off a new heart rate strap that contains both a ANT+ chip and a Bluetooth Low Energy chip within it (Bluetooth Smart).  At first glance, you may wonder why this is important – but once I walk through it, you’ll see the implications are far more reaching than simply displaying heart rate data.  In fact, in my book – this has almost nothing to do with heart rate data.

I’d go as far as saying this easily ranks into the top three coolest sports technology things I’ve seen at Interbike this year.  Mostly, because it’s what a lot of you have been asking for lately – even if you didn’t know you’ve ben asking for it.

But first, to backup a second (or a few seconds).  Typically, if you look at a normal ANT+ heart rate strap (the one that almost everyone out there has today), it reads your heart rate, and then broadcasts that via ANT+ as a sensor device back to any ANT+ compatible unit, like a Garmin wrist watch or bike computer.  This goes the same for speed/cadence sensors and power meters.  That’s worked well for years, but as cell phones have become more prevalent in sports, it’s been harder to get that data onto cell phones (and apps like Strava).  ANT+ countered to solve that by working with cell phone companies to place ANT+ chips in them, like the waterproof Sony Ericsson Xperia Active.  And we also saw companies like Wahoo Fitness developing iPhone/iPod/iPad adapters for ANT+.  However, in large scale we haven’t seen integrated ANT+ chips in cell phones catch on.

Meanwhile, on the Bluetooth side, it wasn’t until the iPhone 4s was announced that we saw Bluetooth 4.0 in any mainstream fashion.  Bluetooth 4.0 enables the ability to connect to Bluetooth Smart devices (aka Bluetooth Low Energy), which can be used in sensors like heart rate straps and other sports scenarios.  I wrote a bunch up on that a few months ago as a primer.  Over the next 6-12 months, it’ll be impossible to find a cell phone without Bluetooth 4.0 in it.  And in many ways, Bluetooth 4.0 is a competitor to ANT+ (though, in today’s form, not yet a replacement for a number of reasons I noted above).

The challenge has been for many people though is how to get that existing ANT+ data (via the stuff you already bought) onto their cell phone.  We’ve seen folks like Wahoo Fitness become extremely successful with ANT+ adapters and cases, but many don’t like the additional bulk.

Thus, what if you had a device that you wore just like any other device – but also did the consolidation of ANT+ data into Bluetooth Smart data, and therefor – straight into your new cell phone with no dongle/adapter/key?

(My couple second historical backup is now complete)

Now you see the potential for something like the heart rate strap based Viiiiva.


At present, 4iiii’s is being a bit limited in what they are saying publically about the strap and the functionality, since they are working with a number of partners ahead of formal release in two months in November.

But after a long technical talk with them this morning – the implications are huge.  Here’s just two scenarios you could potentially do with it:

A) You could be riding a bike with a ANT+ power meter and an ANT+ speed/cadence sensor.  That data is then consolidated into the Viiiiva heart rate strap on the ANT+ side.  From there, that data then gets sent outwards via Bluetooth Smart to your cell phone.  All in real-time.  Plus you get heart rate data from the strap itself.

B) You could be riding that same bike, but now instead with one of the Wahoo Fitness Bluetooth Smart Speed/Cadence sensors, and the newly announced Stages Cycling StageONE Power Meter (via Bluetooth Smart) – and then funnel that data BACK to an ANT+ head unit, such as a Garmin Edge 500.   And you still get that heart rate data.

From a data streaming piece, they are still finalizing those components (since the Bluetooth Smart spec is still being finalized a bit as well).  But expect to see them offer the ability to both act as a formal Bluetooth Smart device in accordance with the Bluetooth Smart device profiles, as well as offer a private Bluetooth Smart channel for applications to take advantage of separately.  I’d suspect the private channel side of things would be required if they wanted to deal with scenarios such as integration with the inRIDE accessory from Kurt Kinetic, which has to transmit/understand roll down and the like.  But this would be a prime area for a partnership to take on that component.


From my discussions with them, while the strap will release in November, expect to see more activity as they hit CES (first week of January), as they’re working with a number of folks in the industry on partnerships.  The strap pricing is still a tiny bit of flux – but will be no more than $99.  For reference, the current Wahoo Fitness BlueHR Bluetooth Smart HR strap is $79, and is the cheapest Bluetooth Smart strap I’m aware of on the market today.

The Viiiiva unit uses a standard CR2032 battery, and they believe even with the dual chips in there, they’ll be able to get close to a years worth of battery.  But for a single $3-5 battery, I’d even be happy if it were just three months.  Of course, since it is a heart rate strap, you’ll still get simple heart rate data transmitted across either Bluetooth Smart or ANT+ from it.

Note that due to the non-multimaster nature of Bluetooth Smart today, you’ll need to choose whether you pair Bluetooth Smart devices directly to your phone (i.e. CADENCE > PHONE), or whether you pair them to the consolidator (i.e. CADENCE > VIIIIVA).  Of course you can always change it.  Not really a huge deal in this context, but just a technical FYI.

In other 4iiii’s news, they are on the verge of releasing an update to their 4iiii’s Sportiiiis heads up display as well as app.  The display will now feature significantly brighter LED lights, as well as a re-arrangement of colors to try and address gaps with those who may be colorblind to certain colors.


The app now has a much easier method of setting zones that in the past:


Further, the clip has been changed from a ziptie clip used in the past, to a quick release style design.  It will ship with three sizes of quick release attachments, depending on your glasses.  Additionally, they’ve also changed the button that controls the unit to be tactile, as opposed to straight touch like before.


And finally, it’s also Bluetooth Smart enabled as well (in addition to ANT+).


I’m definitely excited to see how this evolves, and most importantly, how this shifts the landscape for companies looking to do development, especially apps.  The ability for app developers to use the Viiiiva HR strap to reach ANT+ devices (which has huge penetration) without having to require users to buy a separate dongle, is massive.  Plus, the user gets a heart rate strap out of it.

As always, if you have any questions – feel free to drop them below, and I’d be happy to try and get them answered.  Thanks for reading!


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  1. Very interesting. How do you configure it to do what you want? e.g. collect ANT transmit BTLE or the reverse or some other combination? What ANT+ profiles are they looking supporting at e.g. will it end up with power support given a suitable BTLE spec…

  2. VERY cool! First obvious question is how much will it chafe? lol.

    But you’ve got to start providing a link when ever you say CR2032 to an Amazon search, because instead of $3-5, anyone with a little foresight can get the batteries for between $0.20 and $1.

  3. Anonymous

    I always thought a “just audio only” earbud sport4iii would be compelling. with a remote for both on the bike or running you can control exactly what you want to hear data on. So if I hit a button on the remote I would hear what my current wattage is or another button would alert me to my speed,etc. My eyes stay on the road all the time.

    Wahoo, 4iiii…please?

  4. Ray – will this work with the Sony Xperia Active? I run around with a normal bluetooth HRM and an ANT+ HRM to collate readings for the phone and my Garmin watch.
    This is a step in the right direction.

  5. Very interesting, I wonder if they would also sell a unit that is just the combiner that could be dropped in a pocket or just left on the bike etc? I’m using all ant+ right now and finally found a hr strap that is comfortable, so I’m not in a hurry to change that, but would love to be able to receive the data on my phone.

  6. This is brilliant. You’re correct: I wanted this device and didn’t even know it.

    Question: what about multiple profiles? I have a road, a TT, and a mountain bike, all of which currently have a Garmin GSC10 mounted on them and linked to individual profiles on my Edge 500. How hard would it be for this strap to switch when moving from bike to bike?

    PS – While on this subject, next time you talk to Garmin PLEASE tell them to make switching bike profiles easier. It’s currently buried way, way too deep in the menu tree.

  7. I can’t wait to buy the dual HR monitor!!

  8. Anonymous


    I’m glad that I’m not the only person who thinks that switching bike profiles is a hassle on the Edge 500.

    I regularly switch between a road bike, a track bike, and a sprint erg. It takes too many button pushes to navigate the menus and change the profile.

  9. @Anonymous

    Yep, way too many button pushes. The bike profile switcher should be a top-level menu item right next to GPS Status. It’s ridiculous for it to be so deep.

  10. Anonymous

    Ray, so does this mean that all I have to do is have a Bluetooth smart phone and I can get all my Ant+ data on my app of choice (Garmin Fit, Strava etc?). No more worries about buying a Sony Xperia series. That has Ant+?

  11. Hi Anon-

    Yup, that’s exactly the case. Pretty sweet, huh?

  12. Anonymous

    Ray…correction to above post…I mean Bluetooth lte low energy (Bluetooth smart) phone

  13. No worries, I understood what you meant. Yes, BTLE only (Bluetooth 4.0).

  14. Anonymous

    Thanks Ray,
    I love my Xperia Active…. But Now it means I can look for a waterproof phone that’s a bit easier to type on….and link it with my new Garmin Fenix thru Bluetooth low energy….

    Thanks for your great reviews…..now get baking!

  15. Anonymous

    Wahoo not only pioneered the BTLE HRM, but they re-engineered it, as you pointed out in your review. That was the biggest thing that drew me to ordering one. For the life of me, I can’t get Garmin nor Polar ANT+ HRMs to work reliably. Do you know if 4iiii took the Wahoo route and developed their own sensor, or are they using the same supplier as Garmin, Polar and friends?

  16. I am SO PUMPED about this! With Verizon failing to offer a 4G Ant+ phone (only the HTC Rhyme works), I’ve been agonizing over this. I want my phone to be my one stop shop. Now, with a BT 4.0 phone I’ll be able to pull my ANT+ data, HR data, and GPS all at once AND with the ipBike app, I’ll have direct upload to Strava all from my phone! I LOVE integration!

  17. Not specifically a question to this product – but I have been trying to find a HR strap that can record my HR on the strap for later retrieval. I would like this so I can work out without having my wrist unit/phone on me, for example when playing soccer or basket ball where I don’t want to wear anything that can get caught. Anyone familiar with such a unit?

  18. Jen

    Any word on when this will be for sale?

  19. Russ Sharpe

    OK Ray, where can i buy one of these in the UK?

    • DC Rainmaker

      Regrettably, they aren’t out yet. That said, I’m meeting with the guys tomorrow morning – so hopefully more details then.

  20. John G

    Looks like these are available for sale now. I don’t see any mention of allowing for BTLE device data aggregation (e.g., from a Wahoo BlueSC). Ray, do you have any more info on this device?

  21. AGFlyer

    I just bought one when I upgraded to iPhone 4S as I broke my 4 (didn’t want to have to change the connectors for everything in the 5 just yet…). Can’t wait to get my hands on it! No more Wahoo dongle! Now, I guess my only question is, what running apps are going to be able to use it to pick up the sensors. I use mostly iSmoothRun, as it allows me to program workouts, which then get announced to me through the headphones. Just ordered a set of the new Jaybird BT4 headphones as well, so looking forward to a wireless and dongle-free running experience!

    • A. Dorny

      You and I on the same page. I just took delivery of my 4iii strap yesterday, and paired it easily with my iPhone 4s, as well as with my Suunto Ambit. While wearing my BT jaybirds and rocking out – I completed my run without a technical glitch. Afterwards, i exported from ISmoothRun directly to Garmin Connect and Strava. (I don’t export to Movescount, as the Ambit autosyncs on recharge.) I love the audio cues which makes ISmoothRun awesome. I doubt that I could go on a run of marathon length without discharging the battery of the phone – but thats ok. Most runs should be short enough that I won’t run the battery down too quick with the BT earphones and BT hrm operating at the same time.

  22. sickness

    Well I bought one, but can’t seem to get it to work beyond being a HR strap. The “consolidator” functionality was the reason I bought it, but Garmin & Wahoo are looking for their ANT+ key or dongle. Haven’t found another app that recognizes my footpod & the HR strap for the run, or picks ups my powermeter, cadence, & HR on the bike. Anyone have an app to recommend that works with the viiiiva?

  23. Trevor_L

    Hi DCR, thanks again for a great review. Your comment “due to the non-multimaster nature of Bluetooth Smart today…” leads me to a question. I run a Cycleops G3 Powertap that only transmits Ant+. If I use this heart rate strap with an iPhone 4s, could I also use the Wahoo Rflkt computer using bluetooth from the phone? Thanks.

    • DC Rainmaker

      Yup, assuming your RFLKT is paired to either the Wahoo app or the CycleMeter app, and then from there you’ve got your PT via Viiiiva over BLE. Phew!

  24. Anonymous

    There is so much technology out there, and im a little confused. Are you saying that the Viiiiva strap can replace the whole idea of an ant+ key or dongle- so that even though it alone just tracks heart rate, paired with other ant+ devices it can also transfer data from those? ( i have a timex global trainer and am trying to decide wheather i still need to buy a wahoo fittness key or not if i buy viiiia instead)

    Also, I was wondering if the viiiia is compatible with the huge amount of ios apps that the wahoo is. I was thinking maybe you could take the data that viiiia transfers to your phone, put it on the wahoo app, and then send it out to multiple other fitness apps, such as digifit, runkeeper, map my run, and ect.

    I appreciate your blogging and reviews. Avid reader. thank you.

    • DC Rainmaker

      Hi Anon-

      Exactly, it’s all about replacing the Wahoo dongle/ANT+ key. It essentially acts as a middleman converting ANT+ devices (primarily power meters and footpods) into Bluetooth Smart devices.

      However, with the TGT note you still won’t be able to transfer workouts from it to the phone (because it doesn’t support it).

      But if you want to use your existing ANT+ accessories with the app, the Viiiiva is the way to go.

      It’s semi-compatible with apps out there today. There’s effectively two levels of comparability:

      1) Fully supported: These apps can multi-channel the data from multiple devices and get full resolution 1-second data from ANT+ device to apps (not many apps yet)

      2) Standard support: For apps that support any of the Bluetooth Smart device profiles (i.e. Wahoo, CycleMeter, etc…), then you’ll get a round-robin support where it iterates through each of the channels. This results in less data though (not good for power meters, but likely fine for other apps).

      Hence why you can see the review has ended up being a bit more complex (more areas to test/explain/validate) than I was hoping.

  25. Michele Badiale

    But how does it really work? What kind of BT low energy profile does it use?
    In order to be compatible with “any” ANT+ device I expect it would stream multiple data fields simultaneously (instead of multiple separate fields)… but then only the apps that support it directly could ever use it, right?
    It would be interesting to check if the various sport apps (Endomondo, Runkeeper, Wahoo etc) know about it and are planning on supporting it!
    One of the reasons I don’t like BT-LE is that it can be associated to only one device whereas ANT+ can be associated to as many devices as you wish simultaneously. This device would be great to keep using my ANT+ stuff and receive it both on the watch and the phone :)

    • DC Rainmaker

      What you described is accurate and part of the challenge. Apps like Wahoo/Runkeeper/Endomondo don’t today support the multi-channel aspect, so the Viiiiva for them goes into a round-robin state of basically giving a second of power meter data, then a second of HR data, and so on. So you lose data fidelity in that case.

      Apps that do support the method then receive the full multi-channel broadcast without data loss.

  26. Garett

    I cannot find nor know how to pair the garmin foot pod with the 4iii HR Strap? any help?

  27. Andey

    Does this device work with apps such as mapmyfitness ,strava,road bike pro,etc..,?

  28. Greg


    Zwift doesn’t support bluetooth at this time and not an immediate plan in the future based on what the rep I talked to communicated with me. Anyway, I want to know if this can get my Kurt Kinetic InRide power to work on Zwift? I’m a bit confused on the description up above about the cadence sensor and stages power in BTLE still working with Ant+. Anyway, your input would be great!


    • No, unfortunately the 4iiii’s converts from ANT+ to Bluetooth Smart, but not the other way around.

      In the case of Stages, it’s dual ANT+/Bluetooth Smart. So it can use either protocol.

  29. Graham Smith

    Rubbish! Well, it works well enough, just doesn’t last very long. Junking mine and only 6 months old. Was OK for the first month, then the battery needed replacing, next one lasted about as long, then battery life was down to two weeks and now it just does nothing.

    Read about it on here and was impressed, never dreamed it would have such a short lifetime, reverted to my 5+ year old Garmin now and should save a fortune in CR2032s!

  30. Xavi

    Great article. I havebeen using the viiva HR with my polar V800 and Garmin 500. While working perfectly with the Garmin with the V800 I’m having the following problem:
    Is not showing any HR on any running or triathlon sport profile. Only showing HR on other profiles like bime or skiing. So if I go for a run I cannot use the viiva HR I need to use the Polar HR7. I have tried to reset the V800 and also the Viiva and pair again but same problem.
    Does this makes any sense? I thought Viiva could be used as asingle HR with V800 once uses also BTL
    Thank you in advance for the support