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+--- Thread: Using PhyPhox for lsm9ds1 accelerometer (/showthread.php?tid=1562)
Using PhyPhox for lsm9ds1 accelerometer - ManvirB - 05-05-2022
Hi there,
I am using the Nano 33 BLE board to receive accelerometer data to upload onto 3 separate channels. However I am unable to do so, because whenever I write code for the lsm9ds1 my phone cannot find my Arduino via bluetooth. It just doesn't show up. When I write my own code I am able to connect to my Arduino and display two separate channels. I have included my code below, if possible could someone help guide me towards the solution? Thank you so much
Code:
#include <phyphoxBle.h>
#include <Arduino_LSM9DS1.h>
void setup() {
Serial.begin(115200);
PhyphoxBLE:
tart("Experiment");//Experiment
PhyphoxBleExperiment Experiment; //generate experiment on Arduino which plot random values
Experiment.setTitle("Experiment");
Experiment.setCategory("Arduino Experiments");
//View
PhyphoxBleExperiment::View firstView;
firstView.setLabel("FirstView"); //Create a "view"
PhyphoxBleExperiment::View secondView;
secondView.setLabel("SecondView"); //Create a "view"
PhyphoxBleExperiment::View thirdView;
thirdView.setLabel("ThirdView"); //Create a "view"
//First Graph
PhyphoxBleExperiment::Graph xGraph; //Create graph which will plot random numbers over time
xGraph.setLabel("Graphing x-acceleration");
xGraph.setUnitX("s");
xGraph.setUnitY("m/s/s");
xGraph.setLabelX("time");
xGraph.setLabelY("x-acceleration");
xGraph.setColor("FF0000"); //Sets Color of line
/* Assign Channels, so which data is plotted on x or y axis
first parameter represents x-axis, second y-axis
Channel 0 means a timestamp is created after the BLE package arrives in phyphox
Channel 1 to N corresponding to the N-parameter which is written in server.write()
*/
xGraph.setChannel(0, 1);
//Second Graph
PhyphoxBleExperiment::Graph yGraph; //Create graph which will plot random numbers over time
yGraph.setLabel("Graphing y-acceleration");
yGraph.setUnitX("s");
yGraph.setUnitY("m/s/s");
yGraph.setLabelX("time");
yGraph.setLabelY("y-acceleration");
yGraph.setColor("00FF00"); //Sets Color of line
/* Assign Channels, so which data is plotted on x or y axis
first parameter represents x-axis, second y-axis
Channel 0 means a timestamp is created after the BLE package arrives in phyphox
Channel 1 to N corresponding to the N-parameter which is written in server.write()
*/
yGraph.setChannel(0, 2);
//Third Graph
PhyphoxBleExperiment::Graph zGraph; //Create graph which will plot random numbers over time
zGraph.setLabel("Graphing z-acceleration");
zGraph.setUnitX("s");
zGraph.setUnitY("m/s/s");
zGraph.setLabelX("time");
zGraph.setLabelY("z-acceleration");
zGraph.setColor("0000FF"); //Sets Color of line
/* Assign Channels, so which data is plotted on x or y axis
first parameter represents x-axis, second y-axis
Channel 0 means a timestamp is created after the BLE package arrives in phyphox
Channel 1 to N corresponding to the N-parameter which is written in server.write()
*/
zGraph.setChannel(0, 3);
//Info
PhyphoxBleExperiment::InfoField myInfo; //Creates an info-box.
myInfo.setInfo("In this view you can set a value between 1 and 10. The squared random value will be multiplied by this value and can be seen here.");
//myInfo.setColor("404040"); //Sets font color. Uses a 6 digit hexadecimal value in "quotation marks".
myInfo.setXMLAttribute("size=\"1.2\"");
//Separator
PhyphoxBleExperiment::Separator mySeparator; //Creates a line to separate elements.
mySeparator.setHeight(0.3); //Sets height of the separator.
mySeparator.setColor("404040"); //Sets color of the separator. Uses a 6 digit hexadecimal value in "quotation marks".
//Value
PhyphoxBleExperiment::Value myValue; //Creates a value-box.
myValue.setLabel("Number"); //Sets the label
myValue.setPrecision(2); //The amount of digits shown after the decimal point.
myValue.setUnit("u"); //The physical unit associated with the displayed value.
myValue.setColor("FFFFFF"); //Sets font color. Uses a 6 digit hexadecimal value in "quotation marks".
myValue.setChannel(3);
myValue.setXMLAttribute("size=\"2\"");
//Edit
PhyphoxBleExperiment::Edit myEdit;
myEdit.setLabel("Editfield");
myEdit.setUnit("u");
myEdit.setSigned(false);
myEdit.setDecimal(false);
myEdit.setChannel(1);
myEdit.setXMLAttribute("max=\"10\"");
//Export
PhyphoxBleExperiment::ExportSet mySet; //Provides exporting the data to excel etc.
mySet.setLabel("mySet");
PhyphoxBleExperiment::ExportData myData1;
myData1.setLabel("myData1");
myData1.setDatachannel(1);
PhyphoxBleExperiment::ExportData myData2;
myData2.setLabel("myData2");
myData2.setDatachannel(2);
PhyphoxBleExperiment::ExportData myData3;
myData3.setLabel("myData3");
myData3.setDatachannel(3);
//attach to experiment
firstView.addElement(xGraph); //attach graph to view
firstView.addElement(yGraph); //attach second graph to view
firstView.addElement(zGraph);
secondView.addElement(myInfo); //attach info to view
secondView.addElement(mySeparator); //attach separator to view
secondView.addElement(myValue); //attach value to view
secondView.addElement(myEdit); //attach editfield to view (Linked to value)
thirdView.addElement(myInfo); //attach info to view
thirdView.addElement(mySeparator); //attach separator to view
thirdView.addElement(myValue); //attach value to view
thirdView.addElement(myEdit); //attach editfield to view (Linked to value)
Experiment.addView(firstView); //attach view to experiment
Experiment.addView(secondView);
Experiment.addView(thirdView);
mySet.addElement(myData1); //attach data to exportSet
mySet.addElement(myData2); //attach data to exportSet
mySet.addElement(myData3);
Experiment.addExportSet(mySet); //attach exportSet to experiment
PhyphoxBLE::addExperiment(Experiment); //attach experiment to server
}
void loop() {
float x, y, z;
IMU.readAcceleration(x, y, z);
PhyphoxBLE::write(x, y, z);
delay(1);
}
RE: Using PhyPhox for lsm9ds1 accelerometer - Dominik Dorsel - 05-06-2022
Hey,
your code looks good! I think the problem is within your loop-block:
Code:
IMU.readAcceleration(x, y, z);This line will return a 1 when new data is available (and the datapoints itself of course). If the accelerometer is not ready, you get an 0 and NAN as you can see in the libraries repository:
https://github.com/arduino-libraries/Arduino_LSM9DS1/blob/c10a6c807bbb7200be89ecd236513032a9cf2cc5/src/LSM9DS1.cpp#L109
Since the loop is basicly running with no delay (except this very small 1ms) you will call some "readAccelertion" while no data is available. You should get new data every ~10ms, since the output data rate is fixed to 104Hz in this library (if you want to change the data rate, you might switch to another library - i think the sparkfun one is able to set some settings).
To avoid this, you could go with this:
Code:
if (IMU.accelerationAvailable()) {
IMU.readAcceleration(x, y, z);
PhyphoxBLE::write(x, y, z);
}https://phyphox.org/forums/showthread.php?tid=1026
Let me know if its still not working.
Cheers,
Dominik
RE: Using PhyPhox for lsm9ds1 accelerometer - ManvirB - 05-06-2022
(05-06-2022, 11:41 AM)Hey Dominik,Thank you for your response. I tried to increase the delay but had no success. Thus I read the thread you posted and concluded that I needed to include the first 4 lines of code in the connectionParameters example. I tweaked them to Gautier's numbers as below: PhyphoxBLE::minConInterval = 6; //6 = 7.5ms Wrote: PhyphoxBLE::maxConInterval = 6; //6 = 7.5ms
PhyphoxBLE:
PhyphoxBLE::timeout = 10; //10 = 100ms
However the Arduino still isn't showing up on my phyphox app. Is there something else I am missing? Thank you for your help Dominik!
Dominik DorselHey,
your code looks good! I think the problem is within your loop-block:
Code:IMU.readAcceleration(x, y, z);
This line will return a 1 when new data is available (and the datapoints itself of course). If the accelerometer is not ready, you get an 0 and NAN as you can see in the libraries repository:
https://github.com/arduino-libraries/Arduino_LSM9DS1/blob/c10a6c807bbb7200be89ecd236513032a9cf2cc5/src/LSM9DS1.cpp#L109
Since the loop is basicly running with no delay (except this very small 1ms) you will call some "readAccelertion" while no data is available. You should get new data every ~10ms, since the output data rate is fixed to 104Hz in this library (if you want to change the data rate, you might switch to another library - i think the sparkfun one is able to set some settings).
To avoid this, you could go with this:
Next issue might be the limiting bluetooth low energy rate. Depending on your smartphone and connection quality you will not be able to reach 115Hz. You should also check the phyphoxBLE example "connectionParamter" which allows to tweak the bluetooth paramter. This thread might be helpful aswell, since our french colleagues where able to get this rate with the same arduino setup:Code:if (IMU.accelerationAvailable()) {
IMU.readAcceleration(x, y, z);
PhyphoxBLE::write(x, y, z);
}
https://phyphox.org/forums/showthread.php?tid=1026
Let me know if its still not working.
Cheers,
Dominik
Sorry for the weird previous font. On another note I did some digging and found Gautier's published code. I edited to the following (below) and I got the acceleration in the right format. However, my goal was to create channels of my own, to allow for maximum customizeability. My guess is that the maxConinterval on my previous code isn't the right number, because I am transmitting more data than what Gautier is using. Is there a method to find the maxConinterval I need?
Gautier's Code (edited with my project):
/* Link between Arduino Nano 33 BLE Sense and phyphox app v1
* Allows to choose which experiment the Arduino Nano 33 BLE Sense should execute, using Phyphox.
* by Gautier Creutzer and Frédéric Bouquet, La Physique Autrement / Physics Reimagined, Laboratoire de Physique des Solides / Laboratory of Solid state Physics, Université Paris-Saclay / Paris-Saclay University
* Check our other projects in English and French: www.physicsreimagined.com
*
* This work is based on the phyphox Arduino library developed by the phyphox team at the RWTH Aachen University, which is released under the GNU Lesser General Public Licence v3.0 (or newer).
* This work is released under the GNU Lesser General Public Licence v3.0 (or newer).
*/
#include <phyphoxBle.h>
#include <Arduino_LSM9DS1.h>
char board_name[] = "nano_6"; // to change the name displayed by the board using BLE: no space and no special character
float accx, accy, accz, acc;
unsigned long initial_time, first_time, fourth_time;
float first_difference_float, fourth_difference_float;
void setup()
{
PhyphoxBLE::minConInterval = 6; //6 = 7.5ms
PhyphoxBLE::maxConInterval = 6; //6 = 7.5ms
PhyphoxBLE:
laveLatency = 0; //PhyphoxBLE::timeout = 10; //10 = 100ms
if (!IMU.begin()) { // starting all useful sensors
while (1);
}
PhyphoxBLE:
tart("Manvir's Board"); // the name of the board can be changed at the beginning of the program}
void loop() { // if the sensor is available, the acceleration and a timestamp are written to the BLE server, and then to the Phyphox app
if (IMU.accelerationAvailable()) {
first_time = millis();
IMU.readAcceleration(accx, accy, accz);
first_difference_float = ((float)first_time-(float)initial_time)/1000;
acc = sqrt(pow(accx, 2) + pow(accy, 2) + pow(accz, 2));
PhyphoxBLE::write(first_difference_float, accx, accy, accz, acc);
delay(100);
}
}
RE: Using PhyPhox for lsm9ds1 accelerometer - Dominik Dorsel - 05-12-2022
Hey,
sorry for my late replay.
Quote:However, my goal was to create channels of my own, to allow for maximum customizeability.
Sorry I donnt get it. What do you want to achieve?
Quote:My guess is that the maxConinterval on my previous code isn't the right number, because I am transmitting more data than what Gautier is using. Is there a method to find the maxConinterval I need?The connection interval is the time interval between each data package (which is usually 20 bytes). Since you are limited to 5 floats (on the arduino nano), which are 20 bytes, the connection interval is independent from the number of floats you are transfering with phyphoxBLE::write(); So I think you can stick to Gautiers settings.
Cheers,
Dominik