yea I had already done that before - good news, the robot works! now the only issue i have is reducing the voltage - the total voltage for my competition is limited to 9.6 volts. Is there any way I can replace the 9-volt battery with a AA alkaline pack of 2 AA batteries? The servo power will still come from the 6volt (4 AA alkaline pack).
OR, could you send me proof that the VL and VS are completely independant circuits? the rules state that as long as there is no circuit carrying more than 9.6 volts it is ok.
Ok, I think the problem was with the “home” setting. The button X makes the arm go to its home setting right? The home setting is apparently as crunched up as the robot can get; it still crunches up when I start it, and when I push X. The Madcatz controller is not even connecting to the BOT board; I have been using my SONY wired controller for now - I ran the establishing connection program with both, and hte SONY does not return to the perfect values, while the Madcatz doesnt do anything - it leaves all values at 255 no matter what. So the SONY might be causing a little inaccuracy with the robot, I am trying ot find another (working) madcatz. Is there any way I can reprogram the home setting? Whenever I turn the robot on it scrunches up and I think over time it may damage itself.
Also, I looked over the circuit diagram - I easily found the VS-VL jumper section, so as long as the VS-VL jumper is not there, does this prove they are independant? Or do I need to do more?
This is BASIC programming, so yes the home setting can be changed to whatever you want. However if it is not correct for your arm, you may not have it constructed properly. The elbow (forearm) needs to be lifted 30° from level with the servos centered… Um, I will have to ask Laurent about this when he in online because I can’t remember. Also make sure the remarks ; are removed from the beginning of the lines associated with your arms physical properties.
[code];L6
;Arm_Length con 121 ;4.75" = 121mm (4.75 * 25.4)
;Forearm_Length con 121 ;4.75" = 121mm (4.75 * 25.4)
;Hand_Length con 146 ;5.75" = 146mm (5.75 * 25.4)
;L5
Arm_Length con 95 ;3.75" = 95mm (3.75 * 25.4)
Forearm_Length con 95 ;3.75" = 95mm (3.75 * 25.4)
Hand_Length con 127 ;5.00" = 146mm (5.00 * 25.4)[/code]
If the Madcats one does not work with the establishing connection program try pressing the Analog button. Not all controllers accepts the analog command as well as others.
I think I was too cautious with the arm - I let it “crunch” on itself a couple days ago, and it did not push the servos farther than they are supposed to go, it just seemed like it would.
Now the only problem is access voltage. I am only allowed to use 9.6 volts for the arm. Right now I have a 9 volt battery on the BOT and SSC-32’s VLs, and a pack of 4 AA alkaline batteries (6volts) on the SSC-32’s VS. Can I get rid of that system, and replace it with a pack of 6 AA alkaline batteries (9volts), which is connected to the SSC-32’s VL. Then connect the VL-VS jumper on the SSC-32, and then run wires from the SSC-32’s VL to the BOT board’s VL? Will this work?
Is there a maximum voltage or power that I should be running through the VL and/or VS? Will changing the battery pack as mentioned above improve the strength/speed of the servos?
How many total servos are you powering? You can make a power setup where the batterys power both the servos and the board, with the board somewhat proteced from voltage dips caused by the servo motor starting circuit.
I am powering 6 servos, two of which are the smaller servos used for wrist rotation and gripping. (this is the lynx L6 arm)
How would I make such a system?
I was also wondering if I could just replace the 9volt battery on the VL with a 3.6 volt or less battery. How many volts does the VL require to operate?
You can drop the voltage to the servos down to ~5.7v using LM7805 voltage regulators and a diode. You might need to use more than one regulator depending on how much current the arm servos are pulling. You can run power to the servo control board from the batterys via a diode to isolate the board from the high servo starting voltage drops. Put a large capacitor after the diode to the power to the board to act as a temporary power supply to the board during the voltage drops caused by the servos. There is a simple sketch at the bottom of the below page to show this type of setup.
ok, I got the robot working with a 7.2 V battery pack. The pack is connected to the BOT boards’ VL, the VL-VS jumpers on the BOT board and SSC-32 are connected, and the BOT board’s VS is wired to the SSC-32’s VS. Will this system work permanently? I want to make sure I will not damage any circuits with too much power or something.
Servos can be used up to 7.2vdc without trouble, but micro servos are a bit sensitive to this. They can become jittery. I always use 6.0vdc for my servos, with one exception. I routinely use 7.2 vdc for the hexapod 2 using HS-422 servos. The power setup above is completely acceptable. The Vreg on the SSC-32 and bot Board are low drop out and only require a very little voltage (0.10vdc I think) above the regulated voltage to work well.
Yes, the microservos do seem a little jittery. Could I have a 4AA alkaline battery pack (6v) attached to the SSC-32’s VS, and have a 2AA alkaline battery pack (3v) attached to the BOT board’s VL, link the BOT-boards VL to the SSC-32’s VL, and remove all the VL-VS jumpers?
No you need at least 5.1vdc to get 5vdc from the regulator. It’s an LM2937ES so you can get the specs to be sure of the minimum required input voltage. Most cheap regs require a ful 1 volt or more above the regulated voltage to work. This one is a Low Dropout regulator.
That all depends on how many servos you want to control on the robot. If you are going to be running more than 10, I would not depend on a single battery supply. You can always run the electronics (the VL supply) off a single 9V battery and use the heavier duty battery for the servo (VS) supply.
My preference would be to never run the servos off the same battery as the electronics.
Ok, I run many of my 18 servo hexapods all from one 6.0vdc 2800mAh battery, VS, VL and accessories! The only problem is after a pretty long run time the Logic regulator will no longer be able to provide a stable 5vdc and the microcontroller will brown out. The legs go limp and the robot sits down. Then the battery pack will recover a bit and the robot will get up. Then a few seconds go by abd it does it again. No big deal…
Now if you run a separate 9vdc to the VL input the robot will not do the die and come back to life routine, the robot will operate a bit longer and the servos will eventually not have enough power to hold the body up.
I cannot run the VL on a separate power source because I am only allowed 9.6 volts through a single circuit for my competition - the director said that the schematics of the BOT board are not enough to prove that the VL and VS circuits are completely independant (if they are, then the robot will be legal). So I must prove they are independant somehow, or use the single battery pack.
You mentioned something about power failure in your hexapod when you did this - I am using a Lynx L6 Arm, and do not want it to fail on me in the middle of my competition. Can you give me more details on why the robot suddenly fails, when it fails, and whether the failure damages anything?
Another option I thought of - could I connect the VL-VS jumpers, run 6.0v(from 4 AA alkaline batteries) to the BOT boards VL and the SSC-32’s VL (which would then flow to the SSC-32’s VS because the jumper is connected). Would this setup provide the logic with enough power, and prevent the servos from jerking? Please answer soon, my competition is this saturday and I must begin practicing asap.
If you want to do this, it would only be good enough for the logic supply, not the servos.
You would not have much runtime from the servos with this kind of an arrangement. You best bet if you want to run the logic (Bot Board and SSC-32) and servos from a single battery is to just get a nice 6.0V 2800 mAH battery pack from Lynxmotion and use that. The amount of runtime you get will depend on how many servos you are running and how much they are running.
We need to know what was causing the problem. hehe 
