Asked — Edited

Brushed Esc And Servo Question

Hello,

New to the EZB. Finally started it up.

Two questions:

Q1. Got a couple servos moving. I have a continuous rotation servo It seems to have a significant delay when stopping. Is that normal?

Q2. I got one of these.

http://www.ebay.com/itm/221934520621?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It is not turning the motor. I am powering EZB with 5v 5amp wall switching PS. For the ESC above I have a 6V battery pack which I understood was to drive the motor (which is a 9v motor-- I know it will run slow I just want to test it). When I plug in the battery the EZB powered up at least to some extent... lights came on. That did not seem right. So... I disconnect battery. Tried it with just EZB powered up nothing. Tried it with EZB pwoered from wall and abttery pluged into ESC and nothing still.

Q2a. Do I need something in there to keep power from running back into the EZB?


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#1  

Can you take a photo of how things are connected and put it in this thread? I think it would help people to understand the questions better.

PRO
Synthiam
#2  

Welcome! The delay is momentum - and that's due to gearing. In classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object.

Be careful powering motors with a switching power supply as all power supplies are designed for solid state components and not motors.

#3  

I got my motor to run but I am still confused.

I was using a continuous servo control because ... I was messing with one before that. :-)

So I spotted the PWM slider and tried that.

I note that the motor runs at a duty cycle of like 4-5%. It turns on then reverses. There was effectively zero documentation that came with this ESC.

Here are details I found on the original listing: Package Content

XYS-BL10A ESC (x1)

Product Details

Replacement ESC for 1/16, 1/18 cars
With brake control; 
Working voltage: 4.8V~7.2V; 
Wide working voltage: 4.0V~8.4V; 
Input signal: PPM; 
Driving frequency: 2KHz; 
Output current: continuous: 10A
BEC:5V/1A; 
Compatible motor: 130/180/260/280/380 brushed motor; 
Female JST for power connection and JST male for connecting motor.

I googled and am not finding much but a similar model number turned up and there was a word document describing setting some functions on the device using an R/C airplane controller.

Using this device was in part based on some post in a forum here where someone said he used an esc similar to this to good effect. I can't seem to find that. If someone could point me at that maybe it would help.

PRO
Synthiam
#4  

Do not use the pwm control. The pwm control is for pulse width modulation. You can google to understand more about pwm, but it's irrelevant to your goal. Ignore pwm.

All brushless esc's take a servo signal. so, add a servo control.

Now the operation of the esc most likely needs to learn before it will respond. This is because that's how they work. Some Google will help you find more info on the one you bought. If not, I can't help you and only the manufacturer can.

But the instructions are usually this. Power on esc. Configure servo signal to be neutral position (which is servo position 90) and wait for a beep from esc. Then move to high speed and wait for a beep. Then move to low speed and wait for a beep. Then move back to neutral.

Google should be useful. If you can't find info about your controller they you bought, no one will be able to help you:). My recommendation is avoid cheap Chinese eBay purchases because this is what the result is. If you can, find esc with documentation before purchasing.

#5  

I used to use PWM on the Vex motor controllers but as DJ mentioned it doesn't work very well... Using the servo command instead works way better on these type of motor controllers... The reason is because the servo command closely mimics radio controller commands to these ESCs....

#6  

Just a note this is a controller for a BRUSHED motor. I have googled and read a bit but all the pieces are not coming together. For example, the information on the esc I bought mentions PPM. I spotted this before I bought it but it appeared to me as though they (PPM and PWM) were interchangeable. It appears to me now that they are not but I really do not understand what is being said below.

The bottom paragraph at this link:

https://en.wikipedia.org/wiki/Pulse-position_modulation

"A complete PPM frame is about 22.5 ms (can vary between manufacturer).[5] Signal low state is always 0.3 ms. It begins with a start frame (state high for more than 2 ms). Each channel (up to 8) is encoded by the time of the high state (PPM high state + 0.3 x (PPM low state) = servo PWM pulse width).

More sophisticated radio control systems are now often based on pulse-code modulation, which is more complex but offers greater flexibility and reliability. The advent of 2.4 GHz band FHSS radio control systems in the early 21st century changed this still further."

Sourcing:

the most 'reputable' source for a product like this that I found was hobbyking. I almost bought the device then at the last minute realized it had no 'brake' and no reverse! I looked through the various robot stores online and googled and really didn't turn up anything that looked to distinguish itself as quality or even that had the specs that I needed. Escs for brushed motors are somewhat uncommon it would seem.

I only bought one to see if what I could make work before I commit to a solution when I will need to drive several.

I am open to other approaches like the l298n controllers.. which technically are less expensive.