#1

Hello!

We are a hungarian father and his son (sorry for my poor english). I bought a EZ-Robot Hexapod for my son, who is interested in it.
I bought it from ebay. Unfortunatelly the seller suck me in - as it was advertised as new, and what we got was opened original box and 2 pcs. cracked house servos.
It was the begining of our story.

I'm a hardware development engineer, so I understand what the Hexapod does and why it is working and how ...

There are several problems what we don't understand, I list it:

1. We power on the Six, we connecting - it is working. After a simple movement/action the Six's 1 servo frequently vibrate and give rattling sound - not always the same. If I touch it with my finger I feel which one is vibrating.
Is it normal?
If I fine tuning the servos for 90°, then the problem still exists.
What can I do with this?

2. I try the tracking function of the camera. I trained an object by Six, and if I try Six tracking this object it is locking the object and sometimes Six turn away about 30-40° from the locked object.
What I do wrong?

3. Mobile app
We have mobiles and tablets with several screen LCD resolution, but the deafult mobile app doesn't display perfectly on the screen, for example the left, forward, reverse, right buttons and main background image is not square rather rhombus.
What do I wrong?
OR why I can't change the main's width and height 800x480 pixels?

4. Can the servo's fine tuning values loading on power on to the Six?
We tried to calibrate the servos, but 2-3 couldn't set by mechanically, only by fine tuning.

So, that are the first problems for us. Could you help us?

PS: we live in Hungary/Europe, how can we buy servo for good price? The price is ok, but the shipping charges are very high, for example from Brookstone the shipping and custom charges are 3x more then the servo's price!

Best regards: Zsolt Tóth

#2

Some answers below.

Quote:

1. We power on the Six, we connecting - it is working. After a simple movement/action the Six's 1 servo frequently vibrate and give rattling sound - not always the same. If I touch it with my finger I feel which one is vibrating.
Is it normal?
If I fine tuning the servos for 90°, then the problem still exists.
What can I do with this?


It is normal for a servo under load to chatter or hum. Usually moving it a degree or so will quiet it down, but you will almost always have some noise coming from the robot even at rest.

Quote:


2. I try the tracking function of the camera. I trained an object by Six, and if I try Six tracking this object it is locking the object and sometimes Six turn away about 30-40° from the locked object.
What I do wrong?


Sounds like you have the pan and tilt servos reversed. Try swapping the two plugs with each other, although you may actually have the robot assembled wrong. The tilt should be the lower and pan (side to side) should be the upper servo.

Quote:


3. Mobile app
We have mobiles and tablets with several screen LCD resolution, but the deafult mobile app doesn't display perfectly on the screen, for example the left, forward, reverse, right buttons and main background image is not square rather rhombus.
What do I wrong?
OR why I can't change the main's width and height 800x480 pixels?


Please provide more information on the devices you are using. I have used EZ-Mobile on several Android phones and a Nexus 7 tablet without seeing this issue. Can't provide much other help unfortunately.

Quote:


4. Can the servo's fine tuning values loading on power on to the Six?
We tried to calibrate the servos, but 2-3 couldn't set by mechanically, only by fine tuning.


Six doesn't really need fine tuning. Basic calibration is good enough for all of its movements to work correctly. I would just delete the fine tune profile and use basic calibration (make sure all the levers are attached correctly).

Quote:


PS: we live in Hungary/Europe, how can we buy servo for good price? The price is ok, but the shipping charges are very high, for example from Brookstone the shipping and custom charges are 3x more then the servo's price!



You can buy directly from EZ-Robot. Shipping on just a couple of servos may be a lot. The bigger your order, the less the relative shipping cost, although EZ-Robot is not responsible for customs/VAT charges which vary by country quite a bit.
http://www.ez-robot.com/Shop/Default.aspx?CatId=104

You could also see if any of the European re-sellers here carry the servos and can do better on shipping: http://www.ez-robot.com/shop/retailers

Welcome to the forum, and sorry to hear that you got ripped off by an eBay seller. That must be very frustrating, but I think you will find a small investment in replacing the parts and some time reviewing the lessons and tutorials in the learn section of this web page will give you a long lasting and exciting hobby (note: if ordering Servos, I would order a couple of spares. They do occasionally where out).

Alan

#3

Follow-up on fine tuning. It really is only needed for the JD robot or other humanoid type robots, which relies very much on being able to balance and have all of the movements execute perfectly. Six, Roli, and AdventureBot all work fine without fine tuning.

Alan

#4

Thanks Alan - also, there is a very important section of the website titled learn. The menu option can be accessed in the top menu bar. Press learn and select your robot. There are instructions for your robot and manual pages for the software.

Welcome to the group Smile

#5

Dear Alan!

Thank you very much for your answers!
I have read the lessons...

#6

Great!

EZ-Robot Revolution Six is a great learning platform. There is a great deal of information in the learn section to teach you about servos, programming and electronics. Since you asked about servos, here is a direct link to a fantastic tutorial which explains how servos work: http://www.ez-robot.com/Tutorials/Lesson/48?courseId=6

Keep in mind that ez-robot is unable to identify if your servos are damaged from the previous owner, or simply worn out from use. If the vibration is severe, then i would assume those particular servos are worn and will eventually require replacing.

However, if the servo is vibrating only slightly when weight is applied, the link above will explain why. Servos modulate an electric motor back and forth rapidly to maintain a position. Read the above link to see how servos work.

#7

Alan, he's probably using the default six project - which is already configured for the tracking servos. I can only guess that the camera is facing the wrong way Smile he put the camera on reversed.

If he pushes forward, I bet six walks backwards.

All he has to do is change the camera direction to be correct as per the instructions and voila!

#8

I was thinking about Roli which has pan and tilt where i have seen this before. SIX the camera just sits on top of the body and the whole body moves. DJ is right, you probably have the camera on backwards.....

Alan

#9

Unfortunatelly not, the camera is in good direction.

*********** UPDATE 2016.05.20 ************
Very good news!

1. Paypal granted me - because I was ripped off by seller, I got a FULL refund. ;-)

2. I solved the color tracking problem:


User-inserted image

User-inserted image

I think the solution was that I made a wider grid/ moved the grid lines!

#10

Guys!

I ask who was Hexapod: what time it can play with till battery discharging at 6,6V?
It seems to me that this time is 1/2h appr.