Archive for January, 2012

Logging data from two units

Saturday, January 28th, 2012

Yes­ter­day we sat down and cut-and-pasted together a sim­ple Linux C inter­face to the Open­Shoe. This allowed us to logg data at full speed (820[Hz]) from two units simul­ta­ne­ously. This we have had prob­lems with doing reli­ably from Mat­lab. The prob­lem seem to be that Mat­lab have a very large over­head in its fread-calls. This can prob­a­bly be solved some­how by using large buffers, read­ing a lot of data at the same time, and do some clever pars­ing. This is how we solved it for a sin­gle units. How­ever, for two units we found it eas­ier to just write a C inter­face. This also allowed us to reuse some old syn­chro­niza­tion code of ours. Cur­rently, the C inter­face is kind of uggly, untested, undoc­u­mented so we have not made it openly avail­able yet. Pos­si­bly we will do this in the future. If you have an urgent need for such an inter­face and do not wish to code one your­self (if you have a look at the cor­re­spond­ing Mat­lab con­trol scripts, it is rather straight for­ward), con­tact us and we will see what we can do.

Matlab code for testing

Saturday, January 28th, 2012

It was recently dis­cov­ered that the matlab-code for the Algo­rithm test frame­work was miss­ing from the source­forge repo. This has now been added. Apart from com­mu­ni­ca­tion scripts, this code also con­tains an inter­me­diat ver­sion of the algo­rithms. It is in mat­lab code like the Open­Shoe mat­lab imple­men­ta­tion but it is writ­ten only com­po­nent wise mul­ti­pli­ca­tions like the C ver­sion in the Nav­i­ga­tion algo­rithms repo.