ANT Forum

Hello,

I'm using a USB2 stick and a SDM3 in a little program I wrote in C# with visual c# 2010 express. I'm trying to generate a music note at the very moment the SDM is moved.

And it almost works. Actually, I manage to generate a music note (for information, I send an OSC signal received by Pure Data), but there is a big latency (untill 1 second between the moment I move the sensor and the moment I get the moving signal and untill 2 seconds between the moment I stop moving and the moment I get the "normal" not moving signal).

So do you think it's possible to have more "real time" signals?
Maybe I miss-interpret the messageContent. What are the exact meaning of the 8 bytes like : 02-FF-FF-00-00-00-FF-00 or 02-FF-FF-4C-C2-C6-FF-01 ?
Currectly, I Use the last byte to know if there is a move (0x01) or not (0x00).

My current period is 8134 (approximately 4hz). I have tried to decrease the period, but it becomes very unreliable and I got : EVENT_RW_FIL_0x02

Thanks a lot for your help
Kind regards.

Hugo      

you can find details of the message content in the device profile... and decide which field is more appropriate for you to use as a determinant of whether there is movement or not

http://www.thisisant.com/pages/ant/ant-device-profiles

as for latency... this may just be related to how the device operates... some devices just measure steps, rather than poure movement... therefore the 'movement' isnt communicated until the first step is measured... that is: the time it takes for you to COMPLETE an entire step cycle, rather than the time at which you BEGIN to take a step...

similarly, some device algorithms may have a delay to ensure movement has stopped, before reporting that it has...

the latency of the ANT+ profile is 250ms per broadcast message... any delay longer than that is likely at the application layer of the device...      

Too bad...

If I wait that much it's also because with 4hz (a message every 250ms), I get page 1 twice a second and page 2 twice a second and the motion information seems to be only in page to, So I have to wait 500ms + the time it takes to the sensor to detect a move.

Do you know any other sensor able to do better thant 4hz (100mhz would be ideal) ? Or one which would send raw data (thus directly before detecting a move) ?

Thanks a lot for your answere.      

unfortunately you will have to do the research on different products..      

As I have already developed something, I was hopping for an ANT device, but, I'll take a look elsewhere (most likely to the Wiimote, which I have tested and give good results for a good price but a take more place on a body than a SDM).

Thank you for your help !

Hugo      

there may very well be an ANT/ANT+ device out there that meets your needs... the way a profile is implemented is manufacturer specific... for example, ANT+ defines the message content and general use case/operation ... however, the manufacturer can still define what user actions open and close channels...

You can visit our product directory at
http://www.thisisant.com/modules/mod_product-directory.php

to see a list of ANT+ products and further research these products via their manufacturer to get more details on their performance..