I recently built an AL5D with a bot board 2, basic atom pro, and PS2 controller to control it but when I press the right analog stick up or down (move the wrist) the whole arm drops to the ground and I have to reset the position. Any help would be welcome.
arm1_pro.bas (15.5 KB)
First thing I would suspect with 2 second at the code, which shows that you are using an SSC-32 is the SSC-32 is reseting. Do you have separate power for VS1/VS2 and VL going into the SSC-32? If not, try adding 9v Battery to VL of SSC-32 and remember to remove the VL=VS1 jumper(shunt).
Also I would check to make sure that you don’t have a servo wire that is being pinched and shorted out.
Kurt
Hi, I’m assisting Omega0 with his robot arm. Note that we are using the Lynxmotion PS2 controller w/ Bot Board II. Some behavior we’ve noticed:
- when you try to move the wrist (right analog stick up/down), the arm faceplants
- when the arm is fully extended, the wrist functions normally
sounds like you might be nipping a servo wire. check that all the wires are free from getting trapped or over stretched.
Alright, so we checked for pinched/strained wires and it now dives slower and the wrist will only move up even when we pull down on the right joystick. We have also moved the gripper wire and the wrist wire away from each other to minimize signal interference between the two.
*You wont get interference but good of you to check. *
**1:**Was the wrist wire getting trapped?
**2:**Does the wire on the wrist look damaged?
I would think about replacing the wrist servo.
**3:**Are you using a wall pack or a battery?
We had the wrist wire cable-tied to the shaft of the arm along with the gripper wire, but we cut the ties. The wires don’t appear to be damaged, and we’re using a battery. The main problem seems to be with the bottom “shoulder” servo, since it is the one causing the arm to dive.
Thanks for the quick replies!
if its running slow id expect it to be a power issue. what battery are you using? make sure is it fully charged.
Perhaps you could provide some clear photos showing the wiring. Saying it’s the same as a pictorial schematic doesn’t allow us to look for mistakes or other potential problems. Also is the problem changing from the arm going limp to the arm forcefully faceplanting in some direction?
Checked the battery with a multimeter and it appears to be fine. Also, it seems to be faceplanting at the same speed as before now.
I’m afraid that our configuration is a tad jumbled, so if you would like to see something specific feel free to ask.
Note: The black wire you see to the side broke off just before we took the pictures, yet, oddly, the arm still works like normal.
I’m not sure I quite understand your question, but I can tell you that the arm is never going limp. Whenever we try to move the wrist up/down, no matter how the arm is positioned, the whole thing just goes straight down/“faceplants”.
See for yourself: youtu.be/M6iNogcZchk
Thanks so much for taking the time to help us out!
Im not very familiar with the Arm kits so im not up to scratch with the Assembly or electronics but these things should relate to each other in one way or another.
im a bit confused by that black wire that broke off. the one that should be allowing you to power the ABB.
your still running it with the wire disconnected: 
Does that 6v supply enough current? what battery is it? what the mA rating?
Prob not related to the Face planting but i would also advise that the wires here are trimmed and inserted correctly. many problems can happen if exposed like this. you may even completely damage the boards if the worst was to happen.
Some times using large headed screws can make to much contact to the board. jim once pointed this out to me so its
always worth changing them for the Hex bolts like on the SSC.
also i noticed a few bent pins on your SSC. not related to your current problem but i thought id point that out.
i would sort a few of these things out first and then we can try and find other problems. you never know, a little TLC always helps, and sometimes it can even make these problems go away.
The black wire is a ground wire from the SSC-32 to the Bot Board II. Because these two boards also share a communication connection the boards are still grounded together. So that’s why the board still works with the black wire disconnected.
From the beginning everyone including me thought the arm was going limp due to power issues. But the video clearly shows the arm is just following orders. Where did you get the program? Which tutorial?
I used this tutorial: lynxmotion.com/images/html/build091.htm
and this program: lynxmotion.com/images/files/arm1_pro.bas
Also the arm is actively pushing down as if I told it to.
Ok did you make any changes to the program?
There are instructions to properly set up the arm dimensions in the tutorial. You must set the AL5D perimeters and hide the default AL5B setting in the program. If you didn’t do this the arm can act really weird.
The possibility still exists that there is a wiring error. Did you double check the servos are in the right order?
We changed it to the AL5D dimensions and checked that the wires are in the proper positions and it still doesn’t work.
P.S. we are using a longer aluminum pipe for the wrist to elbow section, I will post the exact dimensions later.
You can’t use a different length than is in the file. It’s not clear to me what is going wrong. Could you post an updated video? It might help to tell us what buttons you are pressing to make whatever happen…
I’m having the exact same problem - see my post from today.
Important clue: every function from the left joystick works perfectly. Now think about that - this means the base servo and elbow servo are both wired properly etc. Otherwise they wouldn’t be able to do the coordinated motion required for left-joystick functions.
But when you move the right joystick, which is supposed to move only the wrist, the base joint goes crazy. And it does this in a completely repeatable manor.
i’m using the same program you are - with no changes other than editing for AL5D per instructions.
good luck - please post the solution if you find it.
I think that while we are working on solving this problem you should try this tutorial. It is newer code written by Xan. It does not use the SSC-32, only the Botboard and Atom Pro. It also drives a differentially steered base but you can ignore that part of the project.