Interfacing RPLidar to EV3/ev3dev #491
Comments
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@bmegli replied
Hardware-Wise: Yes, it should be possible to use it both with USB adapter and directly (soldering somewhat in line with XV11 Lidar, not exactly) The USB adapter uses CP2102 chip for USB2UART bridge. The driver should be already included in any modern linux kernel (CP210x). In fact it's included in ev3dev kernel tree:
So good news - USB2UART bridge used in your adapter should be working out of the box in ev3dev. Anyway, after plugging the device type:
to make sure. Software-Wise later if I have time. |
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More from @bmegli Software-Wise sketch: When you connect the adapter the USB2UART bridge should be reachable at:
You will have to compile the driver/sample applications from the SDK.
Anyway, follow SDK documentation. For building on EV3 you will probably need something along the lines: Maybe something more. You will definitely encounter some problems along the way and get three or four headaches ;-) But... it's also certainly doable. Good luck. |
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Even more from @bmegli Ok, some final remarks and guesses. When you build SDK you will also end up with static or dynamic library with RPLidar driver API. You can use this library also from Java. Ugh, and we should move the RPLidar integration discussion to separate thread. |
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hehehe, @bmegli, I wish I can connect with the sensor using "/dev/ttyUSB0" later, I will try to compile the driver. Last year, I used an Arduino board with LeJOS. If I could use the sensor directly, it could be great. Examples: |
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Oh, ok. I see that you are communicating with it somewhat directly from Java or is it some Arduino library? You don't have to compile the SDK driver library if you don't need it. You can directly communicate using And final remark (ok, so the last final wasn't final): EV3 will not be probably fast enough to read samples one be one and process them at the same time (doing odometry and stuff in below milisecond time). You will probably end up packetizing the LIDAR readings to some say k samples read, processing/odometry and next k samples or some other scheme you can think about (e.g. reading asynchronously and processing odometry in the meantime, whatever you like). |
Or may be not because communicatiation with the device may be different from communication with the adapter (which handles also the engine) |
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Give me some hours, Normally I had the device with Arduino, I am going to test with the USB Adapter. |
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Hi @bmegli, It run nice in EV3Dev!!! I connected the LIDAR 2D with the USB Adapter and the system recognize the device. Later I started reading /dev/ttyUSB0 Details: root@ev3dev:/home# lsusb
Bus 001 Device 003: ID 10c4:ea60 Cygnal Integrated Products, Inc. CP210x UART Bridge / myAVR mySmartUSB light
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubDetails: root@ev3dev:/home# lsusb -D /dev/bus/usb/001/003
Device: ID 10c4:ea60 Cygnal Integrated Products, Inc. CP210x UART Bridge / myAVR mySmartUSB light
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x10c4 Cygnal Integrated Products, Inc.
idProduct 0xea60 CP210x UART Bridge / myAVR mySmartUSB light
bcdDevice 1.00
iManufacturer 1 Silicon Labs
iProduct 2 CP2102 USB to UART Bridge Controller
iSerial 3 0001
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 2 CP2102 USB to UART Bridge Controller
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Device Status: 0x0000
(Bus Powered)I compiled the driver without any problem and I run the example included with the SDK: make[2]: Leaving directory '/home/sdk/sdk/app/ultra_simple'
make[1]: Leaving directory '/home/sdk/sdk/app'
root@ev3dev:/home/sdk/sdk# ls
Makefile cross_compile.sh mak_def.inc output sdk
app mak_common.inc obj prebuild workspaces
root@ev3dev:/home/sdk/sdk# cd output/
root@ev3dev:/home/sdk/sdk/output# ls
Linux
root@ev3dev:/home/sdk/sdk/output# cd Linux/
root@ev3dev:/home/sdk/sdk/output/Linux# ls
Release
root@ev3dev:/home/sdk/sdk/output/Linux# cd Release/
root@ev3dev:/home/sdk/sdk/output/Linux/Release# ls
librplidar_sdk.a simple_grabber ultra_simple
root@ev3dev:/home/sdk/sdk/output/Linux/Release# ./ultra_simple
RPLidar health status : 0
S theta: 1.66 Dist: 00400.25 Q: 30
theta: 2.88 Dist: 00401.75 Q: 26
theta: 4.00 Dist: 00405.75 Q: 20
theta: 5.27 Dist: 00409.75 Q: 12
theta: 6.39 Dist: 00000.00 Q: 0
theta: 6.72 Dist: 00611.75 Q: 14
theta: 7.84 Dist: 00618.50 Q: 16 The another example program run nice too: root@ev3dev:/home/sdk/sdk/output/Linux/Release# ./simple_grabber
Simple LIDAR data grabber for RPLIDAR.
Usage:
./simple_grabber <com port> [baudrate]
The default baudrate is 115200. Please refer to the datasheet for details.
root@ev3dev:/home/sdk/sdk/output/Linux/Release# ./simple_grabber /dev/ttyUSB0 115200
RPLIDAR S/N: 95C299F3C1E39AF2A2E09AF006133230
Firmware Ver: 1.14
Hardware Rev: 0
RPLidar health status : OK. (errorcode: 0)
waiting for data...
***
*****
*****
*****
* *****
* *****
* *****
*******
*******
*******
* *******
** ****** ********
******************
*******************
* ******************** *
**** ******************** ********
***** ******************** ****************
***************************************************************************
---------------------------------------------------------------------------
Do you want to see all the data? (y/n) I suppose that the object used to manage the device is: librplidar_sdk.a I will research a bit to know how to connect with Java. Tomorrow, I will continue with the library. 💃 💃 💃 |
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This is super-awesome! Good job and good luck with further work. |
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One more thing that occured to me.. I sometimes build wrappers for native libraries to .Net. While it is possible to do it manually there are now tools that make it automatically. Same should be true for Java. Before coding a manual wrapper for the API look for a tool that can do it for you (basically generate java classes automatically). The tools are usually not perfect and you have to correct some errors afterwards but they spare you a lot of work. |
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Yes, one alternative could be the creation of a Wrapper. Another alternative could be coding a driver directly. In github, exist some Drivers. The commands to handle this sensor are: Start_Scan = "\xA5\x20" #Begins scanning
Force_Scan = "\xA5\x21" #Overrides anything preventing a scan
Health = "\xA5\x52" #Returns the state of the Lidar
Stop_Scan = "\xA5\x25" #Stops the scan
RESET = "\xA5\x40" #Resets the deviceSo, using this serial library: I could develop a Class to manage RPLidar. Using apt, it is easy to install the library: apt-get install librxtx-javaAnother interesting library could be: In Python side, exist a driver ready to run. Yesterday, I tested it too. root@ev3dev:/home# cd python/
root@ev3dev:/home/python# python LidarPrint.py
/dev/ttyUSB0
Connecting
...
(146, 131)
(147, 132)
(148, 133)
(150, 134)
(151, 135)
(154, 135)
(156, 137)
(158, 139)
(161, 140)
(164, 141)
(166, 142) |
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And another one: JTermios http://www.sparetimelabs.com/purejavacomm/purejavacomm.php Choices, choices... ;-) |
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Ok, I am closing it for now. Let me know if you want to reopen for some reason. To sum up, this is what you have achieved:
C/C++ language: RPLidar is ready to use almost out of the box Other languages: One can probably use the API or communicate using |
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Hi, i am new in this forum, i had try run the code python "LidarPrint.py" with my RPLIDAR A2, but this not funcionally, i only change the next line code: i understand thar i have to change the last code line, because i am working in Debian Software (Linux) and the COM port dont exist, the usb port of the sensor is "/dev/ttyUSB0" when i run this, appears this: I have to work with the sample code of RPLIDAR (ultra_simple, simple_grabber) and this work in raspberry. somebody know what is the problem? @bmegli @jabrena Please, i am waiting for yours responses. this is for mi master's degree tesis. Thank you Sergio Aranda |
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When is the thesis due? |
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Hi, On February but this had to be complete at last days on January. |
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Hi @sarandaegus, First - I don't own RPLidar so my help will be limited. ultra_simple, simple_grabberThose are officially supported by LIDAR manufacturer and you should follow documantation here: http://www.slamtec.com/download/lidar/documents/en-us/LR002_SLAMTEC_rplidar_sdk_v0.1_en.pdf @jabrena followed it and got it working so it seems to be the right path. The easiest would be to build SDK directly on EV3 (e.g. call make in SDK directrory with makefile provided that you have gcc toolchain installed) "LidarPrint.py"As I understand by "LidarPrint.py" you mean that one: https://github.com/jmccormack200/RPLidar/blob/master/LidarPrint.py This is in theory place where you should ask but the repository seems to be abandoned. I would start from the one which tries to start scan and just outputs raw hex data: https://github.com/jmccormack200/RPLidar/blob/master/Lidar_Tests/LinuxHello.py If nothing comes out on the screen I would investigate the connection with the device/tty settings/drivers layer. Maybe @jabrena who owns RPLidar and got it working can be of more help. other waysI would probably start by using some tool I know for serial communication like http://www.slamtec.com/download/lidar/documents/en-us/LR001_SLAMTEC_rplidar_protocol_v0.2_en.pdf This is more-or-less equivalent to LinuxHello.py. other ideasAre you using USB hub? (is RPLidar the only thing plugged to your EV3 USB? If not it may not be /dev/tty/USB0) |
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Hi @bmegli thank you for response. Ok i only use raspberry pi conected for usb port with the RPLIDAR sensor, i dont have EV3. Ultra_simple and simple_grabber is run ok in my raspberry. The problem is when i run LidarPrint.py, now i jut run the LinuxHello.py code, and it is ok, onle appear in my screem : a55a0500004081, only these, the datasheet say me that this is ok, but now i have new question : how control the motor ? it is automatic. And '/dev/USB0' is correctly connected. I am using RPLIDAR A2. the second version sorry for my english Sergio |
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@sarandaegus you should probably be asking those questions at slamtec
Is it automatic or you need to control it? A quick scan through RPLidar SDK docs at slamtec shows that:
So for RPLidar A1 it was somehow connected to serial DTR (it might have been false that made it active, don't assume that enable DTR means set it to true) For RPLidar A2 it is something else. A glimpse through the SDK code reveals that: u_result RPlidarDriverSerialImpl::startMotor()
{
if (_isSupportingMotorCtrl) { // RPLIDAR A2
setMotorPWM(DEFAULT_MOTOR_PWM);
delay(500);
return RESULT_OK;
} else { // RPLIDAR A1
rp::hal::AutoLocker l(_lock);
_rxtx->clearDTR();
delay(500);
return RESULT_OK;
}
}
u_result RPlidarDriverSerialImpl::setMotorPWM(_u16 pwm)
{
u_result ans;
rplidar_payload_motor_pwm_t motor_pwm;
motor_pwm.pwm_value = pwm;
{
rp::hal::AutoLocker l(_lock);
if (IS_FAIL(ans = _sendCommand(RPLIDAR_CMD_SET_MOTOR_PWM,(const _u8 *)&motor_pwm, sizeof(motor_pwm)))) {
return ans;
}
}
return RESULT_OK;
}
... reveals that it sends command RPLIDAR_CMD_SET_MOTOR_PWM on serial with some argument specyfying motor power. To sum up:
Finally - consult your official documentation, everything seems to be there. |
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So you may have to replace: ser.setDTR(False)with ser.write(Set_Motor_PWM)where Set_Motor_PWM is message to be constructed according to RPLidar protocol. You may have to read it's answer also. Consult the docs for the details |
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hi @sarandaegus, The Script which I used was for RPLIDAR v1. Any progress with the comment from @bmegli ? I will buy this new model this year but at the moment, I don´t have the device at home to help you directly. Another alternative for this Script, could be create a wrapper from C output with Python/Java if you continue blocked. Last year, I was testing integrating Python with Java but maybe to avoid this kind of problems another alternative is creating a bridge directly from Driver from Slamtec. Another alternative is using a ROS node, but in this case, the complexity of the solution will increase. Merry Christmas everyone on #EV3Dev Cheers Juan Antonio |
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Hi everybody! Already solved the problem!. I tried another metod, I want to share with you all. Ok, first you need to download the .rar in your raspberry pi. normaly this is the folder. if you know, you need write: make in sdk/ if you wanto to create 'obj' and 'output' and run the demo "ultra_simple" or "simple_grabber". Go to:
Here you add new line code, in my case i need to capture the "theta" and "distance" and transmit via UART port connected xbee module. before that you add new library, because you will use GPIO raspberry, go to:
the new line is in color red, "wiringpi" is a library for GPIO for defect is instally en RPI3, if you dont have this, you need downloand this, and "-lm" this call a library math.h if all is ok, return a sdk and write:
after:
I hope it helps. Thank you Thanks everyone for your help Sorry for my english. Sergio Aranda |
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Congrats Sergio Cheers |
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Ok! Great that you got it working, thanks for the link! I admit I got a little confused what you had working and what you had problem with ;-) Nice mix of LIDAR with XBEE communication. I am closing the issue again, this had little to do with ev3dev from the start ;-) |
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I have connected lidar with raspberry. On board, I have installed QT. Can I get a sample c++ code for reading data from lidar? |
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Depending who you ask and what concerns you. There are examples in official rplidar-sdk See:
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There is also sample C++ code here that I wrote for my private experiments to make this:
But:
Even if unsupported and non-standard, the C++ code for reading from rplidar is there as yet another example. |
But only for windows examples are available, not for Linux. |
I will try this. |
rplidar-sdk examples
are cross-platform (work on Linux). This is the code you are probably looking for (how to read data from lidar in C++). I don't remember about the third example (frame_grabber). It might have been Windows specific. On ev3dev-mapping
This is just if you want the code example. Unsupported means that I am not going to help with running it. Non-standard means that this is not how most people would read from rplidar. It just solves my specific problems which are probably not your problems. Bottom line - try rplidar-sdk examples. |
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Ok, I am closing the issue, this had little to do with ev3dev (again...). |
In bmegli/ev3dev-mapping#1 @jabrena said:
Today, I will try to connect the RPLidar with the USB Adapter directly in order to know if it is possible to receive data:
http://www.slamtec.com/en-US/rplidar/index/5
If you have time, check some PDFs here:
http://www.slamtec.com/static/media/2014/09/rplidar/rplidar_sdk_v1.4.5.7z
rplidar_sdk_v1.4.5\doc\en.US\rplidar_sdk_manual_en.pdf
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