leonardo46
Italy
Asked
— Edited
I tested ARC with hitec servos, and discovered ARC is not able to make them move in their full rotation range, largely exceeding 180.
The full ARC 0-180 range produces a rotation of about 163. And , of course, no corrispondence between the degrees set and the actual servo position.
I was told by DJ Sures, that ARC was made for ezb servos, and compatibility is not guaranteed with hitec servos.
I should suggest EZ to make a software update to ARC to let users configure it to their own servos. I think it shouldn't be a difficult task.
It woulde be useful to many users !
In my humble opinion is not an ARC issue (a new software configuration option) it's a Firmware issue.
The EZB controller has 2 micro-controllers, one is used for the WIFI and the other one manages the hardware ports & speaker.
Both micro-controllers do not support over the air updates, the only solution is to use 3 party tools.
Unless there is an EZR firmware builtin functionality (not advertised until now) to specify the min and/or max servo pulses, i don't see that happening.
currently we are able to flash the WIFI micro-controller :), nothing is impossible but is not so simple.
Let's wait for DJ's answer.
You're right, the limitation must be in the firmware. We can only ask EZ and wait for a future ezbv5 !.... DJ made me see an oscilloscope skecth, showing the pulse range of ezbv3, that was wider than ezbv4 I have. They changed, mantaining compatibility with EZ servos, but not with hitec's.
Unfortunately there will not be changed to ARC to support third party hitec servos. If you wish to use incompatible third party servos, consider adding an arduino or ssc-32 to the ezb as a secondary controller.
@leonardo46 You could try using a servo stretcher like this: https://www.servocity.com/html/180o_servo_stretcher.html
But it will effectively add $20 to the cost of each servo.
Yes, the servo stretcher from Servocity is your best bet for Hitec servos.
I burned up 2 ezrobot mini servos using the ssc-32 by sending 2500us pulse (maximum) to those servos... These servos were possibly pinned against their stops which would of course cause them to burn... After that I restricted my mins to ~600us and max to ~2400us just to be sure to protect from future burned servos....
I have no idea how @DJ set his servo mins and max for ARC and/or firmware, but if it were me doing this I would hard code for a buffer at each extreme to help protect servos from accidently hitting their stops...
Richard, there are, in ezb script, statements to prevent servos reaching their stops. Yes, I might use servo stretchers or other controllers. EZB has greatly reduced my hardware .It does everything ! Unfortunately I'll have to increase my hardware again.
I'm sorry to hear that you have to increase hardware again. however, the ezb firmware is hard coded for the servo max/min positions and cannot be altered. While this may not provide full servo range with your application, it assists tens of thousands of other users by providing pre-calibrated ezrobot servos for their revolution robots, specially in schools and educational facilities.
Adding the ssc-32 is only 2 wires - and will free up many digital ports on the ezb for other features... Such as leds or switches , etc