Hey guys I am still working on the A4WD1/AL5 Arm turtorial lynxmotion.com/images/html/build148.htm and stuck on Step 11 (servo and motor controller calibration). I followed step 11 with Terminal 1 tab: Changed the Baud Rate to 9600, COM port to the port Im using, Echo to NoEcho, then clicked on Connect to change to Disconnect. Finding my robot’s servo offsets is where I start to have problems and begins in step 12. When I run the program the only problem I have with my robot is the elbow servo. According to figure 12 and pressing the “B” button, once I hit the elbow servo it shakes out of control. I press the “A” and “C” buttons to try and decrease and increase the servo offset but does not seem to work. I know the program is running correctly because when I start it and press the “B” button I can see and feel the servos go from Base, Shoulder, Elbow servo etc. etc. Does anybody have any ideas? I posted pics of how my BotBoardII is set up when I run the program. The positive and negative wire that is connected to VS comes from step 5 which is powering my BBII. Also, if more info is needed that I forgot to post let me know. Im really stuck on this problem.
Thanks.
I forgot to mention that I have tried step 13 and placed my robot arm in a 90 degree neutral position and turned it on. It does hold that 90 degree position as shown in figure 13, problem is that the whole arm shakes out of control. I immediately turn it off because Im afraid of damaging something. So Im having problems with Steps 11-13, mainly 12. Im also confused about in the instructions when it says “Use the A, B, and C buttons to straighten the arm as shown in Figure 13”. Hope this helps with any ideas.
What you’re describing sounds like normal servo oscillation, which means you probably have your mechanical dampeners too loose. Tighten them down a little bit. You should be able to easily move the arm when it is powered off. If you can’t, then they are too tight.
Let me know how that goes. 
The other possible cause is the use of a single battery for servos and logic. If they are sharing a single supply it’s possible for the servos to draw too much current, causing the microcontroller to reset. To rule this out attach a 9vdc battery to the VL terminals, and remove the VS=VL jumper. If it still acts weird it’s oscillations. If it is fixed it’s brownout.
Ok Im back with the latest update on my robot. First I worked with the electronics and attached a 9vdc battery to the VL terminals, and removed the VS=VL jumper to see if it was a brownout. It still acted weird, so for now thats all I have to work on is that its oscillations. Working on the mechanics I started with the Base and worked my way up tightening servos, mechanical dampners, the two “C” clamps, the multipurpose brackets for the tubing etc. etc. all the way to the gripper. When I ran the servo/motor controller calibration lynxmotion.com/images/html/build148.htm it pretty much acted the same way. It occured to me that I may be running the program incorrectly but when I do run it all the servos work fine except the elbow servo and now the right motors do not work but the left ones do during the program. For my motor chassis I have two 6vdc batteries that I have soldered together with a battery quick connect cable and one 6vdc to power the BBII. Terminal 1 tab I have 9600, COM port 8, No Parity, No Flow, No Echo, Disconnect. I tried to download a short video (5 secs.) for you of what my robot does when I power it up but its too large, 6 MG. Is their another way of sending it to you? I think it would help out alot if you can see it.
Thanks.
Ok I found directions on how to download videos through youtube. I hope this works. The video shows my robot being powered up Im not running the program, but it acts the same way. As you can see the whole arm is shaking, but thats why Im assuming its the elbow servo.
Oooo…, that’s ugly! 
What the?
Pull the shoulder servo plug out and see what it does.
What is the voltage on the servos?
Are you sure you didn’t connect 12vdc to the servos?
Hi everybody. Well…I pulled the shoulder servo plug out and it still acted the same way. So I plugged that back in and pulled the elbow servo plug out and this is what I got on video. I know its not 90 degrees but it does act normal now, no vibration at all. There is a slight buzzing coming from the servo and if you turn up the volume on your puter you might be able to hear it. Should I be concerned about that? I still am trying to complete the servo/motor controller calibration to make it wireless but what do I do now about the elbow servo? I know the arm is not at 90 degrees and I will fix that first before continuing on with step 12. I havent ran the servo offset program yet but last night the left motors worked, right motors did not. Im new to robotics and looking at the situation what should I do now?
Try connecting ONLY the elbow servo and see if it freaks out or acts cool. If it freaks out it looks like it’s the servo. If it’s acting cool add back in one servo at a time to see if it goes berserk again with more servos. My hunch is it’s a bad servo. We will replace it providing you can produce an invoice number and can return the servo to us.
Ok…when I only connect the elbow servo the arm still shakes but not as much as on the video. Once I started adding the other servos starting with the base I only got to the shoulder and thats when it shook way too much so I just turned off the power. So Im assuming its the elbow. The servo was included as part of a motor/arm combo kit (order#29890) but its way past the 30 day return but I dont mind ordering another one, which I will. Now Im still having problems with the motors of the tutorial lynxmotion.com/images/html/build148.htm, step 7. When I first ran the program I did hear the four ascending notes and the Sabertooth does have power but the motors did not respond to the “A” and “C” buttons. When I continued to the servo controller calibration (step 11) the right motors do not respond, but the left ones did. Sorry I didnt take any pics of the Sabertooth or BBII its kinda of late. I plan on working more on step 7 while I wait for the servo in the mail. If I have any questions about the Tank Mode Test I’ll post it here.
Yeah we’re going to need pictures. 
Another thing to look at is the servo pulses going to that servo. If you have a scope see if the servo pulse is solid or jittery.
Ok…like I said yesterday I worked on step 7 (Tank Mode Test) of the PS2 Control Tutorial lynxmotion.com/images/html/build148.htm. I am having problems with the left and right channels not responding to the BBII. My motors do not seem to respond to the “A” and “C” buttons of a slow forward motion as it explains in the directions. When I power up my robot I do hear the four ascending notes but when I press the “A” or “C” button there is no slow forward motion. The green Status1 LED does glow dimly when power is applied, but does not glow brightly when I am pressing the buttons. In the directions it says this is where it is receiving the pulses from the microcontroller. Does this mean that it is not receiving or sending these pulses?
My first pic is showing how I have my motor chassis set up for the test. I have the Bot Board II powered by a 6vdc with a switch that you can see in the upper/lower left of the pic.
My second pic is of course of my Sabertooth. Even though the upper capacitor is covering the Status1 light it is green. When I press the “A” or “C” buttons it does not light up brighter.
My third pic is my Bot Board with the jumpers in the correct place and Ch.1/Ch.2 in the correct inputs.
So does anybody have any ideas of why this might be happening?
Now Im really confused. I took a break and decided to look at my robot one more time. When I powered up my bot this time, BBII and Sabertooth, the right motors automatically turned about half a turn and the left motors did not turn. It still acts the same way as I described in my previous post but now when I power it up the right motors turn about half way and then stop. Is that weird or what? So do you think my right motors are 100% powered now even though its a half a turn when powered up?
Try attaching two servos to the pins the Sabertooth is connected to. You will need to jumper that block of 4 I/O pins to VS. Then run the program again. When you start it the two servos should be centered. As you press the buttons they should nudge one direction or the other. This would be a good test for the BotBoard II and Atom processor.
Hey Robot Dude…quick question. I havent tried your suggestion yet but this morning before I was going to, I was checking each motor separately with 6v to see if they had power which they did. On the last motor I accidently clipped part of the capacitor lead on it. I am still able to thread the capacitor lead through the terminal its just shorter now. Im sure thats not going to cause any problems with the motor, right? If it does do you guys sell them in packs? Anyways…I plan on trying out your suggestion later on today. Thanks.
The truth is those motors do not draw enough current, and are not “noisy” enough to even use the caps. We put them in because people are used to having caps on motors, but practically they are not required. We don’t sell them separately, sorry…
I have two Sabertooth units to work with on this project because on the first one I was not able to get a green power Status1 light and I thought there was a short in the Ch1/Ch2 wires because the motors were acting how they are now. Anyways…I did attach two servos to the pins the Sabertooth is connected to (8,9,10,11). I was a little confused when you said I will need to jumper that block of 4 I/O pins to VS. I took two pics of placing the jumper in two different positions and they both responded the way that you described. I ran the program again, heard the four ascending notes,Sabertooth did have a green Status1 light and the two servos did have a center position. When I pressed the buttons they did nudge one direction or the other, but the motors did not respond to the “A” and "C " buttons. I also noticed the Sabertooth with the green Status 1 light did not glow brightly when I pressed the buttons even though the servos were responding. The other Sabertooth with no green Status 1 light acted the same as the first one except I could hear a very faint quiet clicking noise. I had to put my ear up to it, but it is there. I took two pics of the BotBoardII and was wondering which one is correct as far as the jumper placement. So does this mean that the BBII and the Sabertooth are at least sending/receiving signals? If so why are the motors not responding to the buttons? Any ideas?
Thanks.
The jumpers place either 5vdc from the regulator or the raw servo battery voltage (VS) to the power pins on that 4 row section. When you are powering servos you use VS, when you are powering sensors and stuff you use 5vdc.
If you’re in the mood for pictures can you take some images of the Sabertooth wiring?