Pan and Tilt Solution

Projects General Guidance
1

Hello, first project, making a pan and tilt system using Arduino uno as the controller.
Objective: Video production, Part-time. Using 6 servos for a Pan/Tilt, operating with
3 HDC cameras.
Components:
Extending,Transmitter and Receiving signal boards, using 100 ft. cat 6 cables.
Each two servos is powered with a 5V DC, 2A adaptor.
Arduino powered with a 6V DC, 1A adaptor.
Heavy Duty Servos: Torque 6V (Kg-cm/Oz-in): 13.2/183
Potentiometer x 6, 10k. Would like to increase to 12, for better, smoother control.

Requiring help with

1st. ATmeg 328 micro chip Not accept programming. Error Code
Upload
avrdude: verification error, first mismatch at byte 0x0000
0x0c != 0x00
avrdude: verification error; content mismatch

2nd ATmeg 328 micro chip Accept programming:
One Servos frozen in a fixed position, one move slightly and chip get warm.

3rd ATmeg 328 micro chip Accept programming:
Servos move erratically. Turn potentiometer one millimeter to left or right and quickly turn 180 degrees left or right, no control.

4,
Sensitivity: At first, two servos working OK, with 100 ft, cat 6 cable.
After adding two more potentiometer and servos, sensitivity issues, between potentiometer and A0 to A3 on the board.
Not touching the cable, move hand over input cables and the servos would be agitated. Used shielded or twisted cable, same response.
Placing a capacitor on 4500 uF on DC in put for servos and 10 uF on potentiometer output DCV and ground.
And a diode on potentiometer output, between signal and ground lessen the sensitivity.
Still having erratic movement with second arduino board, one board is dead.

I have purchased a 3rd board and working with two servos and seems to be working, with a little sensitivity on the signal line.
Before I try another experimental, complete setup with third board. I would like some advice, suggestion of what I might be doing wrong or other application to make this project a success?
Can the old board and chip be salvage?
Thanks

2

You probably need to post your code per #7 below. Most servo issues go back to not having an adequate external power supply or poor grounding between the arduino and servo. Have you gotten the servo "knob" example to work with a servo?

http://forum.arduino.cc/index.php/topic,148850.0.html

3

I assume you've tried it with shorter cables? I really don't know at what point cable distance becomes an issue with servos, but it might be helpful to know if any of your problems are related to length/distance. I believe you can go 100 meters with Ethernet, but Ethernet has specific protocols for the signals and impedance matching and you are just sending a timed pulse down the wire.

4

zoomkat Thanks for the reply.

Please explain: You probably need to post your code per #7 below. First time using the forum.

I was able to work two servos with the knob.
Wrote a program for 6 servos and two servos worked. After applying two more potentiometers the problem started.

5

zoomkat:
You probably need to post your code per #7 below. Most servo issues go back to not having an adequate external power supply or poor grounding between the arduino and servo. Have you gotten the servo "knob" example to work with a servo?

http://forum.arduino.cc/index.php/topic,148850.0.html

zoomkat Thanks for the reply.

Please explain: You probably need to post your code per #7 below. First time using the forum.

I was able to work two servos with the knob.
Wrote a program for 6 servos and two servos worked. After applying two more potentiometers the problem started.

6

So, just to be clear, you have the code for 6 servos on the Arduino right now and you have all 6 servos attached to the external power supply and the Arduino output pins? Then you attach 2 potentiometers as your input devices and 2 servos work? Then you attach 4 more potentiometers and it moves eratically?

Are the potentiometers on the 100ft cable or are they local to the Arduino and it's the servos which are remote? 100ft of cable is a bad idea for a 5V analog input. It will pick up all sorts of interference over that length. Usually you should design so that the digital signals do the long-haul distance. If you must put analog on a wire that long, then a 4-20mA "current loop" type of control is ideal as that is immune to most types of interference.

"As per #7 below" means "click on this link below and look for item number 7 on that page."

7

Thanks, DVDdoug and MorganS
Answering both questions.
No, I have not use a shorter cable and will do so for testing.
Reason: Technical Support from The supplier, assured me, their Servo Motor Transmitter Board and Receiver Board, will transmit, PWM signal 100 ft., on a cat 6 cable. Yes, it did work with two potentiometer.
When two more potentiometer was added, major jitters started.
The 100 ft. cat cable is a major concern for camera positioning during a video shoot.

Potentiometer input a anolog signal into the Arduino and output a digital signal, pulse with modulation to the servos.
Setup: Three Servo Transmitter, each supporting two servos only.
Two potentiometer input arduino and two output, very little problem.
Adding two and four more potentiometer, the major sensitivity started.
Gain some result by adding capacitors and resistors.
Yes. I will have to take into consideration ground problem, testing.

If there are other method of building this pan and tilt control, appreciated.

8

Adding two and four more potentiometer, the major sensitivity started.

Did you also add more servos when you added more pots? Without your code and how you are powering the arduino and servos, you are pretty much on your own.

9

Zoomkat
Two more servos was added, powered with a 5VDC 2A adaptor. Test run 4 servos.
Each pair of servos is powered separately.
Result on second set of servos. They are both panning and tilting at the same time on one potentiometer.
Having problem with ATMEG chips. On the third chip and it does 180 turn either way on simple potentiometer turn.
ATMEG chip 2. Servos goes into 45 degree angle, no movement.
Third chip, no output response , not accepting programming.

10

As you are using multiple power supplies, I have to ask the question:

Have you connected all the GND (negative) pins of the power supplies together, and to an Arduino GND pin?

11

@Arduinoproj1, you have posted here 5 times now but there is still no sign of you posting your code - why not?

...R

12

Reason: Technical Support from The supplier, assured me, their Servo Motor Transmitter Board and Receiver Board, will transmit, PWM signal 100 ft., on a cat 6 cable. Yes, it did work with two potentiometer.

What boards are these? How do they play into your arduino/servo project? Are you trying to power the servos with 5v thru the 100' cables? Too much mystery stuff in your project.

13

Robin2:
@Arduinoproj1, you have posted here 5 times now but there is still no sign of you posting your code - why not?

...R

Sorry, first time using such a site and not aware of the protocols.
Read the how to instructions and need some help in posting code, where?
Thanks

14

The code tags can be written directly as

[code]your code here[/code]

I think the problem may be "crosstalk" or capacative coupling between the servo wires. Is this 100ft cable a ribbon cable? Do you have all of the servo control wires run together with power and ground on the side? One possible solution is to use a wider ribbon cable and put a ground wire in between each active signal wire. That way the energy radiated by the digital signal is absorbed by the ground instead of creating spurious signals in the adjacent control wire.

It's probably not the code. If it works for 2 then it should work for 6. The difference between the two tests is that with potentiometers disconnected, the command to those servos will be zero or 100%, which is a DC voltage for a PWM pin. (For a servo, it will be a synchronised pulse for the un-used 4, which may be suppressing the noise or the effect of the noise.)
15

MorganS:
It's probably not the code.

You are very brave :slight_smile:

...R