ANT Forum

Hi,

I am new to the ANT,
we want to monitor the heart rate with Fitcare device.
Already we bought the "ANTAP281M4IB" and connected to an microcontroller.
I just finish reading the "D00000652_ANT_Message_Protocol_and_Usage_Rev_5.1.pdf"
for getting stated , I need to know the answer of these questions:
please kindly help me with those.

1- First of all , is the ANT2 module is slave or the heart rate module is the slave?
2- How can I found which channel should I open on the ANT module?
3- what is the data coming from heart rate module ? I mean how can I parse the message?
4- what step should i take to initialize the ANT module?
5- is there any documents of sample code for that?

another thing about your website, in some pages i see the message that I do not have authorize to see that page, How should I solve this as well?

looking forward to hearing from you.
Ali


     

Hi Ali,

The ANT+ Heart Rate Device Profile details the channel parameters and the message format of your received packets.

ANT+ HR sensors broadcast using an ANT master channel, and you can receive from it using a slave channel. You can find an embedded ANT+ HR example on the bottom right of the Downloads page.

If you do not have access to all of the free material, you must upgrade your account from Basic to ANT+ Adopter by passing through the clickthrough agreement.

Cheers,
Harrison      

Dear Harrison,

Thank you so much for your help, I got the docs and seems all information that i need are there!
Again thanks for your support.

King Regards,
Ali
     

Dear Harrison,

Hope you are fine,

Now I can comunicate with ANT and my setup commands are like this:

ANT_AssignChannel(0,0,0);
ANT_ChannelId(0,0,120,0);
ANT_ChannelPeriod(0,8070);
ANT_SearchTimeout(0,30);
ANT_ChannelRFFreq(0,57);
ANT_OpenChannel(0);

The ANT module answers to each message without error. however after ~75 seconds it give the time out message.

Could please also help me with the next step should I take?

I mean for pairing to the heart rate.

Cheers!
Ali      

Dear Ali,

You also need to set the ANT+ Network Key, the channel defaults to the ANT Public Key when it is not set.

Best regards,
Harrison      

Dear Harrison ,

Thanks for your great support .

yup! yesterday after reading the "Device Pairing" document I found out the missing Network Key.

Now I can read the Heart rate from the Master!

King Regards,
Ali      

Dear Harrison,

Thank you so much for your great support.

Now we can read the heart rate from the heart rate band.
After the ANT device paired with the heart rate band we can also get all information such as serial number, manufacture ID, etc
.
I already finish reading the “Device Paring” document.

Here is my question. Would be perfect if you could guide me again.
If there are more than on heart rate bands, how can I get the serial number of each one and then let the user to select one of them and then connect to it?

Because the device type of all heart rate bands is 120, I confuse a little bit.
Please let me know how should I deal with this?

King Regards,
Ali
     

Hi Ali,

The Device Number and Transmission Type fields contain the "extended device number", which should be a 20-bit number unique to each device. You should be able to use that to differentiate the different heart rate straps.

Cheers,
Harrison      

Hi Harrison,

I've discovered four different ways that devices record ANT+ ID:

1: In the ant_device_number field -- field number 21.
2: The last 16 bits of the serial_number -- field number 3.
3: The last 16 bits of a mystery field -- field number 24.
4. The first byte of the ant_transmission_type (field number 20) plus the ant_device_number field (field number 21).

Is there a precedence logic that should be applied to discover the actual ANT+ ID? For example, if both an ant_device_number field and ant_transmission_type field are present, how do we know if the actual ID is just the ant_device_number, or the extended device number with the prepended ant_transmission_type?

Thank you!      

Hi,

I'm not sure where your "field number" values come from, but I can explain some precedence around the terms "device number", "extended device number", "transmission type", and "serial number".

The 16-bit device number was originally the only way to signify the uniqueness of an ANT+ device, but as the market grew larger, a need arose for a larger unique identifier, leading to...

The 8-bit transmission type field, which for ANT+ devices used to only be 0x05. As the upper nibble was not being used, manufacturers now append an additional 4-bit unique value to create an extended device number which looks like this:

Extended Device Number == Transmission Byte Upper Nibble || Device Number. A 20-bit value in total.

But some devices, like HR straps, tend to be used in large group settings, or for unique user identification, in which case a larger value than 20-bits is useful, hence the serial number. The manufacturer's information data page lists an additional 16-bits to make the device more unique, but requires listening to the device long enough to find the value, or forces the receiver to make a request for the data page. This results in this logic for the Serial Number:

Serial Number for Device == Serial Number from Data Page || Transmission Byte Upper Nibble || Device Number. A 36-bit value in total.

Hope that helps clear up any confusion.

Cheers      

Thank you very much for the info! The field numbers I'm referring to are defined in the profile.xlsx contained within the FIT SDK. I'm interested in how to discover ANT+ ID from an already-recorded FIT file, not from the "on the wire" ANT+. With 4 different ways to record the ANT+ ID in a FIT file, it's not clear which should be used if more than one is present.