ANT Forum

This is a general two part question related to ANT technology. To set the stage, we are talking about tracking either individual athletes or a group of athletes (2-8) during exercise. They will all be fitted with a yet to be determined hardware device for HR as well as GPS, both devices supporting ANT+. The goal is to transmit the data in real-time to a single coach's device.

So the questions are really is this something we can accomplish without the athlete wearing a receiver. And what is the range of the ANT technology? If they were looping a track for instance, how far away could they be before we lose it and is there any way to boost the signal?

Thanks in advance.      

ANT+ heart rate straps typically don't exceed a range of about 2-3 meters according to my experience.
Which is a perfect fit for normal use.
So if your coach isn't sitting on an 8 seater tandem with the athletes you'll need a retransmission approach.

Cheers,
OMB      

Thanks very much for the response. Is there any documentation on"retransmission" anywhere? I would love to explore this a bit more.

Thanks again!      

The starting section of the ANT Message Protocol and Usage doc describes some of the possible topologies, but if you need additional range you could have ANT devices act as "re-transmitters" around the track, ie. they scan for ANT messages and then send them again with the same device ID.

If you didn't wish to go down that path and didn't mind paying for a more off the shelf solution, there is also an ANT+ Member company called North Pole Engineering which has a device called the WASP. It uses ANT Continuous Scan Mode to pick up ANT messages over the air and forwards them over WiFi. A few of these could be set up around the track to collect sensor data.      

Hi Harrison, I'm interested in this solution about "re-transmiters" but I'm absolutely lost about where to find it...      

The new devices like 920XT and Fenix 3 have built in wifi. Maybe its possible to write an device app(connect iq) that forward sensor data (with channel ids) to a web server over a web socket/or standard socket? I don't know if its technically possible to run wifi and tracking an activity at the same time on the device. This would only require wifi coverage of the track and a software solution.

I took a quick look at the connect iq api communication. It seems as its only possible to communicate with a mobile phone using BLE with the garmin connect mobile app as proxy to the internet. So there is not support for direct wifi connection.

I read in the BLE that the range may be up to 100m, so maybe its technically possible to use makeJsonRequest to send real-time data during an activity.      

Thanks you !! The problem is that I need this to develope a software that must receive at least 50 heartrate straps and I've read that Bluetooth only allows receiving 7 nodes info :-( This is the reason because I choosed the ANT+ technology option... But range is so short...      

ANT and BLE use the same physical hardware and RF spectrum so the effective range is similar between the two.

The nRF51 SDK does have an "ANT Relay" example, though with 50 heart rate straps you would need an additional device for each athlete to mount to someone's wrist or so to repeat the channel.

There is a company which does mass tracking of heart rate straps called MYZONE, they use custom hardware which can get a greater range. However, in their use case everyone is facing the front of the room so the receiver can stay above/in front and not as greatly affected by the human body. Water is unfortunately an excellent absorber of 2.4GHz radio waves.

A company called Delphian makes a highly amplified module which can achieve 1000m range at the cost of power consumption which supports ANT and could also potentially be a solution.      

Harrison,
I read following article that compares ANT vs BLUETOOTH.

http://electronicdesign.com/mobile/what-s-difference-between-bluetooth-low-energy-and-ant

The range for both the technology is 50 meters. Can ANT chips be used for Indoor tracking/positioning as Beacons ?

     

Yes.