Sit bone distance API

This documentation is intended to help designing applications for the Velobox' vmkstationd3

that include communication with Velometrik's controller for pressure mats.

Commands

The bluetooth communication between the Velometrik controller and an application API of the Velobox runs through several layers:

config min_rawvalue <value>
- Set lowest accepted raw value from pressure sensor mat.Values lower than that value will be regarded to be noise.
- (This method is from the early days of Velometriks to adapt different sensor charges.It might be replaced in the near future.)
switch create_jpeg on|off
- Switch the creation of JPEG pressure images on or off rsp.
switch create_norm on|off
- Switch the creation of normalized pressure value on or off rsp.
sound [ready]
- Play acoustic ready message.
set jpeg colorcontrast 0-7
- Set color contrast
- Changing the color contrast will affect the other Apps too.
set jpeg bgcolor <#HEX value>
- Set background color.
- Changing the background color will affect the other Apps too.
set jpeg grid no|dotted|solid
- Shows or doesn't show the grid that separates the measuring points
set jpeg grid no|dotted|solid
- Shows or doesn't show the grid that separates the measuring points
set jpeg resolution 1-...
- Sets the number of pixels generated per measuring point
- Although there is no upper limit, a large number will probabely knock out the Velobox.
set jpeg frame 0-...
- Draws a black frame around the created image with the value in px.
set jpeg quality 0-100
- Sets quality for JPEG compression
version
- Query Version
- The versions of vmkstationd (key vmkstationd) and of the application (key app) will be returned.

JSON responses

Every JSON response has the key "wsevent" which classifies the JSON message. Depending on the message class there may be more keys specific for that message class. Until now there are the following definitions:

WSEvent	Detail keys	Notes
hockerbild		A new JPEG image is available at <velobox>.local/hockerbild.
hockernorm		normalized pressure values
	imagetype	"ska_live"
	n_rows	number of rows
	n_cols	number of columns
	values	pressure values 0...255(The maximum (if any) is always 255.)
		values start with the 1st column of the last line and end with the last column of the 1st line.
restart		restart of measurement(Last results are not valid any more)
sitzknochenabstand		result
	sitzknochenabstand	sitbone distance in cm
	schwerpunkt1_x	center of left sitbone
	schwerpunkt1_y
	schwerpunkt2_x
	schwerpunkt2_y	center of right sitbone
	schwerpunkt_x	overall center of pressure
	schwerpunkt_y
	gewicht1	percentage of weight left
	gewicht2	percentage of weight right
ttychange	change	plugged\|unplugged
	start	started reading (ok\|error if plugged)
	type	mat type MT_STD
	driver	(used as identifier)
ttystate	state	active\|inactive
	driver	(used as identifier)