Thank you for the detailed step-by-step. I’m having a few issues with this thing. The left side of the robot is not responding to the software. Also, when I click all 1500 legs go all over the place and hit each other, not even close to 90 degrees. You mentioned I needed to adjust but I have no idea how to adjust. The instructions on lynxmotion website seem outdated. I dont know the exact placement of the brackets over the horns after I center the servos so I might have been connecting the horns to all brackets all wrong. I bought the servo tester to help me center the servos which I seem to be able to do that but even when I centered all servos in the first leg (RFL), it does not go into 90 degrees. Please help and thank you
@sulleyboo0 The system indicates this is the first time you’ve posted - do you have a second user profile here? Which robot do you have? Can you link to the other post(s)?
An easy way to remove the bracket is to remove the center screw connecting the horn to the servo and flex the bracket slightly outward so it can spin free of the spline, then re-position it to the right angle and slide it over the nearest spline and add the screw. Some points to consider regarding orientation:
Ensure the servos are oriented correctly as per the guide - installing the driving horn on the wrong side means the servos will move in the wrong direction.
When the servos are centered (receiving 1500us command), the bracket needs to be attached at 90 degrees. For the shoulder servo, this means tangent (90 degrees) to the body. For the other two, they need to be at 90 degrees as in the image here: http://www.lynxmotion.com/images/assembly/h3r/new/hex04b.jpg
Since there are only 24 teeth to a servo spline, there’s a strong chance that each joint won’t be exactly at 90 degrees, which means they need to be “calibrated” slightly. You can tell which need calibration by again sending a 1500us command to all servos and seeing which are slightly off.
@cbenson Yes this is the first time I post and this is my only used profile. I have T hex 4dof robot I’m building.
I was able to figure out how to center the servos following exactly the method you indicated above. I’m using the metal horns sold on robotshop with 4 screw holes. So orientation is where I’m having the biggest issue. I would like to respond to what you wrote step by step to make it easier to understand me since I’m very new to this.
By servo orientation you mean that they all have to be centered (using the servo tester tool) before attaching the brackets to them. So does that mean that when I install the brackets to the servos, I have to assume the 90 degree position before they start wiggling and bending around as I install other legs? following the assembly guide on lynxmotion website, is the final image they have of each leg in the guide is how it is supposed to be as I attach brackets to the servos? like in this link below:
Am I supposed to attach brackets to the centered servos with figure 15 or figure 16 in mind?
What do you mean when you say shoulder? is that the same as hip? and there is hip horizontal (closest to chassis) and there is hip vertical so not sure which do you mean unless you were referring to the one in the image you sent which is different from the one I have. I just need to know the exact orientation of the bracket-servo when I put the screws on after making sure servos are centered.
In terms of calibrating when there is slight deviation from 90 degrees, is that done through the software when connecting to the computer?
3 - It can be done one of several ways - we’ve found the easiest (if you’re up to it) is either sending the offset command to the SSC-32U, which it stores in memory, or adding offsets within the Arduino code itself.
The reason we discontinued the complete 4DoF T-Hex kit is that the Arduino code has not been officially ported / tested internally, and we have not put together then updated guide. We apologize for this inconvenience. As such, the software part of that page is entirely irrelevant to you.
To do the fine calibration, you might disconnect the BotBoarduino (temporarily), and connect only the SSC-32U to the computer. Lynxterm (setup button) allows you to set each offset and save it / write it to the board. Just ensure the board is powered and at the right / corresponding baud rate, and keep in mind that the offsets are saved to the SSC-32U, not the BotBoarduino. http://www.lynxmotion.com/p-567-free-download-lynxterm.aspx
I’m a little confused and I really apologize for being slow.
if the software part is irrelevant so what am I supposed to used to code this thing? I assume from what you said that I should screw the brackets with the centered servo (using a tester) following these pictures (without being attached to the computer but as I’m assembling them), is that correct?
Again, am I supposed to screw the brackets to the horns following image 6-10? so I can say they are all centered so once I click all 1500 in the software they all go to the correct centered position. thanks
Another question, I have not been able to get power to the botboarduino by connecting it to SSC-32U. However, if I connect the power source directly to Borboarduino, it powers and lights up fine. Could you please help with this as well.
my number one issue is centering this thing now and coding/power issues to botboarduino can come later.
if the software part is irrelevant so what am I supposed to used to code this thing?
The software part is necessary. You’ll use the Phoenix code for the 3DoF robot, though this is found in the 3DoF setup: http://www.lynxmotion.com/images/html/build99f.htm
The change will be the addition of the extra DoF per leg.
I assume from what you said that I should screw the brackets with the centered servo (using a tester) following these pictures (without being attached to the computer but as I’m assembling them), is that correct?
Correct. A servo tester is ideal.
Again, am I supposed to screw the brackets to the horns following image 6-10?
In those orientations / at those angles, yes.
Another question, I have not been able to get power to the botboarduino by connecting it to SSC-32U. However, if I connect the power source directly to Borboarduino, it powers and lights up fine. Could you please help with this as well. my number one issue is centering this thing now and coding/power issues to botboarduino can come later.
Let’s start with servo calibration first - don’t worry about the BotBoarduino for now. Center the servos as best you can using the servo tester, then attach all of the servos to the correct pins on the SSC-32U following the pinout in this image.
L eft R ight R ear M iddle F ront K nee V ertical H orizontal A nkle
Connect the power harness to the VS1 terminals of the SSC-32U, ensuring that the VS1=VS2 jumpers are in place (in the correct orientation). Download and install Lynterm, and connect to the SSC-32U via USB. Again, no BotBoarduino yet.
Prop the robot body up so the legs can be free to move.
Click “all 1500” and the servos should move to the correct positions. If not, they need to be centered (missed a step before).
Once they are all close to center, click “Setup” and take a look at the popup to see you can change the offset servo by servo, and then at the bottom “Write” to write the offsets to the SSC-32U controller.
@cbenson I just finished centering all servos, and connected all of them to the right places as instructed. I did connect the battery and to the computer through USB. When I click “all 1500”, only the right side of the robot moves (even though I centered all of them, they still come off off center a little which I assume I can adjust through the software. However, the entire left side of the robot is not moving at all and RFA and RRA are not moving either. I’m really confused and dont know where to go from there. I dont know why all those servos are not moving or responding to the software as if they’re not connected at all. I attached a few pics of what I have. Please advice.
The jumpers we need to see are unfortunately hidden / not very visible in the second photo, but it looks like they are in the wrong orientation and both need to be rotated by 90 degrees in order to make VS1 = VS2 (i.e. share the same power source).
@cbenson I just took more pics. I’m just so confused as to why only some of the servos are responding. Is it a power thing? Is there a specific way I should be connecting the servos to the board, like the way the wires should connect (maybe should be flipped?). I feel like I’m getting the issues that nobody gets.
Hi @cbenson, that worked and all legs are responding, not all completely centered but not all servos are responding, at least three are not responding when I click “all 1500”. Please advise
Triple check that the connectors are plugged into the SSC-32U in the correct orientation (yellow to pulse, black to ground)
If there are servo extension cables, check that when they mate, the colors are aligned (yellow to yellow, black to black).
If this doesn’t solve it, check which servos these are and see if they’re all connected to the same section of pins on the SSC-32, and if other servos work if you swap them with the pins in question.
There are several ways to “fine tune” the angles, but the easiest is using Lynxterm: http://www.lynxmotion.com/p-567-free-download-lynxterm.aspx
This only works with the SSC-32U, so you’ll need to disconnect the BotBoarduino, and only power the SSC-32U and connect it to your computer via USB. Select the right BAUD rate and COM port and connect. Click “All 1500” to set all servos to center.
Under “Setup”, you’ll have the option to fine tune each servo, and then write the offsets to the SSC-32U.
Note that these settings are written to the SSC-32U, so if you use that elsewhere in the future, you’ll need to rest the offsets.
On the left side of the setup window, you should be able to move each individual servo. Proceeding one servo at a time, knowing which servo is plugged into which pin on the SSC-32U, adjust the offset value until the joint angle is visually as close to perfect as you can get., then move onto the next, until you have calibrated all servos (should only be a small offset for each of less than 5 degrees). We’ve found that setting / supporting the body of the robot on something so the legs are free makes it easier. Once all joints are done, click “write”.
I was trying to do that. When I click all 1500, they all go to 1500, however when I try to fine tune, only the right side is responding and the left side is not. Please advice.
