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tlfong01
tlfong01
8:29 AM
@AdrianMaire Buffer: Ah yes, I did use "character buff" when playing with arduino C++ UART projects. I am using python "bytes" data structure, converting to bytes list, which is a list of bytes, and then converting to hex string to print out, therefore making a big mess.
Anyway, I will stall for a short while, and resume when I finish testing the FeeTech FE-URT-1, converter of UART to SMS Servo (RS485) & SCS Servo (TTL). But I don't know nothing about RS485. So it might take me some time to get to know them.
AliExpress sells FE-URT-1 at US$14. Here is the link:
Feetech FE-URT-1 Multi function serial port signal converter USB/URAT to SMS Servo (RS485) &SCS Servo (TTL) US$14
https://www.aliexpress.com/item/32950717029.html?spm=a2g0w.12057483.0.0.302e5164TwNRBM
I bought my FE-URT-1 from TaoBao (like AliExpress, belonging to AliBaba) for 40 yuans. In case you are jealous the we can buy cheap, you must understand we workers here also got paid as cheap.
飞特总线舵机USB转485.TTL信号转换板 举报 价格 ¥40
https://item.taobao.com/item.htm?spm=a312a.7700824.w5003-22502491750.30.4d2638268KcqxT&id=560546097733&scene=taobao_shop
 
tlfong01
tlfong01
9:05 AM
Now I am reading the URT1 board product features/guide and making a summary. The translated version's English is lousy. I guess I might need to Chinese version to clarify things.
Just thinking aloud. Nothing urgent. No need to reply.
URT-1 Offline adaptor/interface board for Feite SMS and SCS servos reading notes:
01. Can select USB to 3V/5V signals.
02. Two kinds of signals: (a) Asynchronous half-duplex RS485 for SMS serial servo, (b) - Asynchronous half-duplex TTL-level for SCS servo.
03. URT-1 board has "hardware time multiplex automatic bypass" (not sure what it is, perhaps just full duplex to half duplex by hardware.
04. Two interfaces: (a) SMS serial servo interface using 5264-4AW, (b) SCS series servo interface using 5264-3AW interface.
 
tlfong01
tlfong01
9:20 AM
There are two versions of the board: Old and New. Mine is new. :)
Locking down supper time! Will come back late this evening to start testing. Cheers.
 
 
1 hour later…
Adrian Maire
Adrian Maire
10:30 AM
Sound good! :-)
Alternatively, we could create our own servo driver. We buy the best motor/sensor we can find (at correct price), and use some cheap 2yen ARM with UART to drive it. This way we could even have Sin movements or similars
For the 555, I need to print a small board (that means to remember all the process or etching, etc.). It's taking to me some time.
 
 
3 hours later…
tlfong01
tlfong01
1:56 PM
@AdrianMaire Yes, my long term (3 year) goal is to use Cortex M0 Micro Python, or BBC MicroBit micro python to drive it. But before that, perhaps we can do some sort of pair programming/development: You Cortex M4 C/C++, me Rpi4 python. My short term (1 year) goal is to build a robot cat/dog/turtle, using 4 servos.
@AdrianMaire Yes, PCB etching is time consuming. For prototyping, I prefer to use bread board, then proto board. I once thought of learning Eagle PCB CAD, but the learning curve is too steep for me casual hobbyists.
Anyway, I have downloaded the FeeTech URT1 Board. It took me some 15 minutes to find the correct software programs.
(1) CH340C driver download address:
Http://www.wch.cn/download/CH341SER_EXE.html
(2) FD V1.6 .exe download address:
https://drive.google.com/file/d/0Bybjet9xBXeqN2JBNmphUXkxSDQ/view
Now I have wired the hardware, and started the FD1.6 debug program.
For Win10, I need to set power switch to 5V. I first set to 3V, but then the CH340 driver was not detected. It took me 10 minutes to find that out. I use 6V to power the servo. I forgot if the max is 7.5V (no longer 11~12V for LX-224HV). But for RS485 servo, the power is 8V~24V. I hope I can use 24V for torque servos, yes higher that 12V of LX-224HV, so those HiWonder guys can not LOL at we FeeTech guys.
Anyway, I started the FD1.6 debug tool, and my first impression is that compared to the HigWonder debug board targeted to perhaps 12~16 school children using BBC MicroBit, this FeeTech debug board can entertain Arduino/Rpi users well. The FD1.6 interface looks complex and I think industrial automation engineers should find this tools helpful.
Looking back, I am glad your LX-224HV half duplex program introduced me to the new world of Serial Bus Servos. As I said some days ago, I feel inferior and losing face playing with TowerPro MG995 toy servos, using PWM to do the vary limited control, and open loop, no feedback from the servo to do closed loop control projects.
Ah, bed time! Call it a day. Cheers.
 

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