Difference between revisions of "Matrix - Potentiometer"
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− | [[Matrix - Potentiometer| | + | [[Matrix - Potentiometer/zh|查看中文]] |
− | == | + | ==Introduction== |
− | [[File: | + | [[File:Potentiometer .png|thumb|Potentiometer]] |
− | + | *The Matrix-Potentiometer module is a Potentiometer module. It can be used in audio control, motion control, transducers, computation and etc. | |
− | + | *3 Pin 2.54mm spacing pin header, V is supply voltage, G is ground and S is output analog signal. Users can convert output analog signals to digital signals via ADC conversion. | |
− | * | + | *Output Voltage: 0 ~ Vcc |
− | * | + | |
− | == | + | ==Features== |
* GPIO | * GPIO | ||
− | * | + | * Small |
− | * 2. | + | * 2.54mm spacing pin header |
− | * | + | * PCB Dimension(mm): 8 x 24 |
− | [[File: | + | [[File:Potentiometer.png | frameless|400px|Potentiometer_PCB]] |
− | * | + | * Pin Description: |
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
− | | | + | |Pin || Description |
|- | |- | ||
− | |S || GPIO | + | |S || Analog GPIO |
|- | |- | ||
− | |V || | + | |V || Supply Voltage 5V |
|- | |- | ||
− | |G || | + | |G || Ground |
|} | |} | ||
− | == | + | ==Basic Device Operation== |
− | + | *A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. | |
+ | *This module mainly contains a potentiometer where the resistance changes with changes between the contact and one end terminal. | ||
− | == | + | |
+ | ==Applications== | ||
+ | The Matrix-Potentiometer module outputs analog signals which can be converted to digital signals through an ADC converter e.g. the Matrix-Analog_to_Digital_Converter module.<br> | ||
+ | For more details about the Matrix-Analog_to_Digital_Converter module refer to wiki:[[Matrix_-_Analog_to_Digital_Converter/zh|Matrix-Analog_to_Digital_Converter]]。<br> | ||
+ | |||
+ | ===Connect to NanoPi M1=== | ||
+ | Refer to the following connection diagram to connect the module to the NanoPi M1:<br> | ||
+ | [[File:Matrix-Potentiometer_nanopi_m1.jpg|frameless|600px|Matrix-Potentiometer_nanopi_m1]] | ||
+ | |||
+ | Connection Details: | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Potentiometer || | ||
+ | |- | ||
+ | |GND || NanoPi M1 Pin9 | ||
+ | |- | ||
+ | |5V || NanoPi M1 Pin2 | ||
+ | |- | ||
+ | |S || Matrix-Analog_to_Digital_Converter A0 | ||
+ | |} | ||
+ | |||
+ | ===Connect to NanoPi 2=== | ||
+ | Refer to the following connection diagram to connect the module to the NanoPi 2:<br> | ||
+ | [[File:Matrix-Potentiometer.jpg|frameless|600px|Matrix-Potentiometer]] | ||
+ | |||
+ | Connection Details: | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Potentiometer || | ||
+ | |- | ||
+ | |GND || NanoPi 2 Pin9 | ||
+ | |- | ||
+ | |5V || NanoPi 2 Pin2 | ||
+ | |- | ||
+ | |S || Matrix-Analog_to_Digital_Converter A0 | ||
+ | |} | ||
+ | |||
+ | ===Connect to NanoPi M2 / NanoPi 2 Fire=== | ||
+ | Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire.<br> | ||
+ | [[File:Matrix-Potentiometer_nanopi_m2.jpg|frameless|600px|Matrix-Potentiometer_nanopi_m2]] | ||
+ | |||
+ | Connection Details: | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Potentiometer || | ||
+ | |- | ||
+ | |GND || NanoPi M2 Pin9 | ||
+ | |- | ||
+ | |5V || NanoPi M2 Pin2 | ||
+ | |- | ||
+ | |S || Matrix-Analog_to_Digital_Converter A0 | ||
+ | |} | ||
+ | |||
+ | ===Connect to NanoPC-T2=== | ||
+ | Refer to the following connection diagram to connect the module to the NanoPC-T2:<br> | ||
+ | [[File:Matrix-Potentiometer_NanoPC-T2.jpg|frameless|600px|Matrix-Potentiometer_NanoPC-T2]] | ||
+ | |||
+ | Connection Details: | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Potentiometer || | ||
+ | |- | ||
+ | |GND || NanoPC-T2 USB Host GND | ||
+ | |- | ||
+ | |5V || NanoPC-T2 USB Host 5V | ||
+ | |- | ||
+ | |S || Matrix-Analog_to_Digital_Converter A0 | ||
+ | |} | ||
+ | |||
+ | ==Compile & Run Test Program== | ||
+ | Boot your ARM board with Debian and copy the matrix code: | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ apt-get update && apt-get install git | ||
+ | $ git clone https://github.com/friendlyarm/matrix.git | ||
+ | </syntaxhighlight> | ||
+ | If your cloning is done successfully a "matrix" directory will be generated. | ||
+ | |||
+ | Compile and install Matrix: | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ cd matrix | ||
+ | $ make && make install | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Run test program: | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ matrix-adc | ||
+ | </syntaxhighlight> | ||
+ | Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.<br> | ||
+ | Here is what you should observe:<br> | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | The channel0 value is 2460 | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | ==Code Sample== | ||
+ | This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-analog_to_digital_converter". Here is its source code: | ||
+ | <syntaxhighlight lang="c"> | ||
+ | int main(int argc, char ** argv) | ||
+ | { | ||
+ | int i = 0; | ||
+ | int value = 0; | ||
+ | int channel = 0; | ||
+ | |||
+ | if (boardInit() < 0) { | ||
+ | printf("Fail to init board\n"); | ||
+ | return -1; | ||
+ | } | ||
+ | |||
+ | if (argc == 2) | ||
+ | channel = atoi(argv[1]); | ||
+ | system("modprobe "DRIVER_MODULE); | ||
+ | signal(SIGINT, intHandler); | ||
+ | for (i=0; i<ADC_READ_TIMES; i++) { | ||
+ | if (pcf8591Read(channel, &value) != -1) { | ||
+ | printf("The channel%d value is %d\n", channel, value); | ||
+ | } else { | ||
+ | printf("Fail to get channel%d value\n", channel); | ||
+ | } | ||
+ | } | ||
+ | system("rmmod "DRIVER_MODULE); | ||
+ | |||
+ | return 0; | ||
+ | } | ||
+ | </syntaxhighlight> | ||
+ | For more details about this APIs called in this code sample refer to [[Matrix API reference manual]] <br> | ||
+ | |||
+ | ==Resources== | ||
+ | |||
+ | <!--- | ||
+ | ==Download Matrix Source Code== | ||
+ | All the matrix modules' code samples are open source. They are maintained on GitHub :https://github.com/friendlyarm/matrix.git <br> | ||
+ | Each branch in this hub contains the matrix modules' code samples for a board that the matrix modules can work with.<br> | ||
+ | * The matrix-nanopi branch contains the matrix modules' code samples for the NanoPi; | ||
+ | * The matrix-nanopi2 branch contains the matrix modules' code samples for the NanoPi 2; | ||
+ | * The matrix-tiny4412 branch contains the matrix modules' code samples for the Tiny4412; | ||
+ | * The matrix-raspberrypi branch contains the matrix modules' code samples for the RaspberryPi | ||
+ | |||
+ | Please follow the steps below to get the source code:<br> | ||
+ | Install the git utility on a PC running Ubuntu14.04<br> | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ sudo apt-get install git | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Clone the matrix code from GitHub | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ git clone https://github.com/friendlyarm/matrix.git | ||
+ | </syntaxhighlight> | ||
+ | If this is successful a "matrix" directory will be generated, which will contain all the matrix modules' code samples.<br> | ||
+ | |||
+ | ==Connect to NanoPi 2== | ||
+ | ===Hardware Connection=== | ||
+ | Please refer to the following connection diagram to connect the Matrix-Potentiometer to the NanoPi 2:<br> | ||
+ | [[File:Matrix-Potentiometer.jpg|frameless|600px|Matrix-Potentiometer]] | ||
+ | |||
+ | Connection Details: | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Analog_to_Digital_Converter || NanoPi 2 | ||
+ | |- | ||
+ | |SDA || Pin3 | ||
+ | |- | ||
+ | |SCL || Pin5 | ||
+ | |- | ||
+ | |5V || Pin4 | ||
+ | |- | ||
+ | |GND || Pin6 | ||
+ | |} | ||
+ | |||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |Matrix-Potentiometer || | ||
+ | |- | ||
+ | |GND || NanoPi 2 Pin9 | ||
+ | |- | ||
+ | |5V || NanoPi 2 Pin2 | ||
+ | |- | ||
+ | |S || Matrix-Analog_to_Digital_Converter A0 | ||
+ | |} | ||
+ | This module's output signals are analog signals. You can use our Matrix-Analog_to_Digital_Converter to convert them to digital signals.<br> | ||
+ | Please connect the Matrix-Analog_to_Digital_Converter to the NanoPi 2 and then connect Pin S of the Matrix-Photoresistor's pin header to Matrix-Analog_to_Digital_Converter's A0.<br> | ||
+ | For more details about the Matrix-Analog_to_Digital_Converter module please refer to wiki: [[Matrix_-_Analog_to_Digital_Converter]].<br> | ||
+ | |||
+ | ===Compile Test Program=== | ||
+ | Please login the matrix hub and enter the nanopi2 branch | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ cd matrix | ||
+ | $ git checkout nanopi2 | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Compile the Matrix code | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ make CROSS_COMPILE=arm-linux- clean | ||
+ | $ make CROSS_COMPILE=arm-linux- | ||
+ | $ make CROSS_COMPILE=arm-linux- install | ||
+ | </syntaxhighlight> | ||
+ | Note: please make sure to install the cross compiler "arm-linux-gcc-4.9.3" on your PC, which is used to compile files for the NanoPi 2.<br> | ||
+ | Generated library files are under the "install/lib" directory. The test program is under the "install/usr/bin" directory. Its test program is "matrix-adc".<br> | ||
+ | The modules are under the "modules" directory. Its driver's source code is in https://github.com/friendlyarm/linux-3.4.y.git <br> | ||
+ | |||
+ | ===Run Test Program=== | ||
+ | Please insert a TF card which is flashed with Debian to a Linux host and mount its boot and rootfs sections.<br> | ||
+ | We assume the rootfs is mounted to /media/rootfs then please run the following commands to copy the driver, library and test program to the card.<br> | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ cp modules /media/rootfs/ -r | ||
+ | $ cp install/lib/* /media/rootfs/lib/ -d | ||
+ | $ cp install/usr/bin/* /media/rootfs/usr/bin/ | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Insert this TF card to your NanoPi 2, power on and run the following commands to load the driver.<br> | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ cd /modules | ||
+ | $ insmod pcf8591.ko | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Please run the following command to test the Matrix-Potentiometer module.<br> | ||
+ | <syntaxhighlight lang="bash"> | ||
+ | $ matrix-adc | ||
+ | </syntaxhighlight> | ||
+ | Here is what you should expect:<br> | ||
+ | [[File:matrix-adc_result.png|frameless||matrix-adc_result]] <br> | ||
+ | |||
+ | ===Code Sample=== | ||
+ | <syntaxhighlight lang="c"> | ||
+ | int main(int argc, char ** argv) | ||
+ | { | ||
+ | int i = 0; | ||
+ | int value = 0; | ||
+ | int channel = 0; | ||
+ | |||
+ | if (argc == 2) { | ||
+ | channel = atoi(argv[1]); | ||
+ | } | ||
+ | |||
+ | for (i=0; i<ADC_READ_TIMES; i++) { | ||
+ | if (pcf8591Read(channel, &value) != -1) { | ||
+ | printf("channel%d value=%d\n", channel, value); | ||
+ | } else { | ||
+ | printf("Fail to get channel%d value\n", channel); | ||
+ | } | ||
+ | usleep(10000); | ||
+ | } | ||
+ | return 0; | ||
+ | } | ||
+ | </syntaxhighlight> | ||
+ | ---> | ||
+ | |||
+ | ==Update Log== | ||
+ | ===Feb-24-2016=== | ||
+ | * Added link to the Chinese version | ||
+ | ===June-23-2016=== | ||
+ | * Re-organized and simplified wiki |
Latest revision as of 14:27, 23 June 2016
Contents
1 Introduction
- The Matrix-Potentiometer module is a Potentiometer module. It can be used in audio control, motion control, transducers, computation and etc.
- 3 Pin 2.54mm spacing pin header, V is supply voltage, G is ground and S is output analog signal. Users can convert output analog signals to digital signals via ADC conversion.
- Output Voltage: 0 ~ Vcc
2 Features
- GPIO
- Small
- 2.54mm spacing pin header
- PCB Dimension(mm): 8 x 24
- Pin Description:
Pin | Description |
S | Analog GPIO |
V | Supply Voltage 5V |
G | Ground |
3 Basic Device Operation
- A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
- This module mainly contains a potentiometer where the resistance changes with changes between the contact and one end terminal.
4 Applications
The Matrix-Potentiometer module outputs analog signals which can be converted to digital signals through an ADC converter e.g. the Matrix-Analog_to_Digital_Converter module.
For more details about the Matrix-Analog_to_Digital_Converter module refer to wiki:Matrix-Analog_to_Digital_Converter。
4.1 Connect to NanoPi M1
Refer to the following connection diagram to connect the module to the NanoPi M1:
Connection Details:
Matrix-Potentiometer | |
GND | NanoPi M1 Pin9 |
5V | NanoPi M1 Pin2 |
S | Matrix-Analog_to_Digital_Converter A0 |
4.2 Connect to NanoPi 2
Refer to the following connection diagram to connect the module to the NanoPi 2:
Connection Details:
Matrix-Potentiometer | |
GND | NanoPi 2 Pin9 |
5V | NanoPi 2 Pin2 |
S | Matrix-Analog_to_Digital_Converter A0 |
4.3 Connect to NanoPi M2 / NanoPi 2 Fire
Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire.
Connection Details:
Matrix-Potentiometer | |
GND | NanoPi M2 Pin9 |
5V | NanoPi M2 Pin2 |
S | Matrix-Analog_to_Digital_Converter A0 |
4.4 Connect to NanoPC-T2
Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-Potentiometer_NanoPC-T2
Connection Details:
Matrix-Potentiometer | |
GND | NanoPC-T2 USB Host GND |
5V | NanoPC-T2 USB Host 5V |
S | Matrix-Analog_to_Digital_Converter A0 |
5 Compile & Run Test Program
Boot your ARM board with Debian and copy the matrix code:
$ apt-get update && apt-get install git $ git clone https://github.com/friendlyarm/matrix.git
If your cloning is done successfully a "matrix" directory will be generated.
Compile and install Matrix:
$ cd matrix $ make && make install
Run test program:
$ matrix-adc
Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.
Here is what you should observe:
The channel0 value is 2460
6 Code Sample
This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-analog_to_digital_converter". Here is its source code:
int main(int argc, char ** argv) { int i = 0; int value = 0; int channel = 0; if (boardInit() < 0) { printf("Fail to init board\n"); return -1; } if (argc == 2) channel = atoi(argv[1]); system("modprobe "DRIVER_MODULE); signal(SIGINT, intHandler); for (i=0; i<ADC_READ_TIMES; i++) { if (pcf8591Read(channel, &value) != -1) { printf("The channel%d value is %d\n", channel, value); } else { printf("Fail to get channel%d value\n", channel); } } system("rmmod "DRIVER_MODULE); return 0; }
For more details about this APIs called in this code sample refer to Matrix API reference manual
7 Resources
8 Update Log
8.1 Feb-24-2016
- Added link to the Chinese version
8.2 June-23-2016
- Re-organized and simplified wiki