Lynxmotion SES V2 Hexapod Robot

kurte · March 10, 2020, 6:36pm

Note: I often end up with feature creep

One thing I am missing in the above board, that I often like in my controllers is some form of audio feedback. Often it does not need to be much, but things like, if I press a button on PS4 controller, I might want a beep to tell me that it registered. Sometimes multiple beeps to let me know I cycled through options… Like the old Botboard 2 and Botboarduino.

So I am playing around with trying to add buzzer. Normally I used a CUI 12mm size one, but don’t think it will fit here. So looking at hacking in a 9mm size one. Often times I try to add in transistor, diode, resistor. Sometimes though I just hook directly to IO pin. Will start off trying that. In above picture will try to move around the transistor/resistors for the level shifting to make it available. Probalby for T4 to pin 10 (which has some additional sound capability MQS). Maybe jumperable to what is DAC0 on T3.6…

But again feature creep.

scharette · March 10, 2020, 6:58pm

@dialfonzo

scharette · March 10, 2020, 6:59pm

What about just placing 2 male headers, the transistor, diode and resistor instead? This also allows you to place the buzzer anywhere using jumper wires, such as somewhere on a robot!

kurte · March 10, 2020, 8:58pm

I could do that (put in most everything but buzzer.
Currently I do have it hacked up to put in small buzzer as I mentioned it is using the CUI 9mm version that is setup for 3v. Could still add support hardware, but I have also gotten away with running their 12mm version by just connecting them to IO pins. And could go fancier and put in a simple mono amp, and connection for speaker, but maybe overkill for now. I suspect that when we go to RPI4, some of us will probably hook up sound to RPI4. Too many possibilities for time sink!

kurte · March 10, 2020, 10:12pm

I might mention that my earlier board (about 11 days ago), just got back to OSHPark and shipped today. So should be here in a day or two

Not sure how long before I can pick it up and feel safe opening and not possibly worry about Cornavirus… But like many packages right now it might be a few days.

dialfonzo · March 12, 2020, 3:48pm

To All…!
@kurte @xan @zenta @cmackenzie

I’m going to finish and cut the proper “beta” center plates so i would like to have any input about it.
Right now it’s about the size of the Phoenix and has holes for the Pi / LSS Adapter.

Let me know so we can have this ready for you guys.

kurte · March 12, 2020, 5:44pm

Sounds good.

Size of about Phoenix? Nice size, but will be interesting to see where everything will fit. That is especially when we graduate up to fully using RPI for things like ROS2 and will want some form of 3d Camera or scanner… Again not sure which sensors Robotshop will want to go with ROS support.

Again things like: IMU. I have a few different ones around here to play with including a few like the BNO080. Including one from Sparkfun with QWIIC connectors, which makes it nice to plug in?

3D camera and/or Lidar… Again can go with something simple like Lidar Lite, or a full Lidar? and/or 3d Camera?
Turtlebot 3 comes with their Lidar:

and some of them with the RPI camera. Earlier with Intel RealSense camera.
I believe that Trossen Robotics went with Intel RealSense and Orbec camera…

And if you want to go whole hog, one could go like the new UP kit coming out:

Note: I am not expecting Robotshop to ship us all of these things, but simply mentioning this as you may want to maybe think through how you might do a setup that allows for some of these sensors and potentially a suggested set.

One approach I know that Trossen did with some of theirs is to have two top plates, likewise for TB3.

Here is my current kitchen sink version of the above board:

Pretty much same as previous one, but added the transistor, resistor, diode to drive the buzzer. Also possibility of connecting an 12mm battery under the board to keep things like RTC running. … May play a little more and order set.

Not sure where I will order from (which is safer virus wise): probably OSHPark, but PCBWay has a nice price and will get them faster. But is it safe? Not sure.

EDIT: made a few more edits, like allow room for Pololu 1 amp DC/DC converter, moved SND source jumper to a place you can get to easier and changed DC power jack to a slotted version to make it easier to solder. Ordered a set of 3 from OSHPark. plus put the current files (diptrace files plus zip sent to oshpark) up on my github project

dialfonzo · March 12, 2020, 6:41pm

I don’t expect this plate to be anything final but would like to get a general idea of size at least.
Here is what it looks like compare to Phoenix:

cmackenzie · March 12, 2020, 10:03pm

It looks good to me! It looks like the Phoenix has more slot space for wiring, even fitting USB sized cabling through it

xan · March 13, 2020, 8:44am

Looks good!

Am I correct that the dotted rounds will be the axis of the servos? So the body will be a bid wider then the phoenix but not much longer.

dialfonzo · March 13, 2020, 10:59am

Exact - The dots / circles are the servos output shaft location.

dialfonzo · March 13, 2020, 2:44pm

Here are the center plate files as they are.
If anyone want to have a look i’m open to changes of course.

SESV2-Hexapod-Center-0.1.zip (130.5 KB)

bdaouas · March 13, 2020, 6:34pm

The LSS Adapter has 10K pull-ups on the FT232 IC Rx and XBee Rx on the 5V and 3.3V side of the BSS138 mosfet

zenta · March 13, 2020, 8:03pm

Looking good!

I hope you all are doing fine on these Covid-19 days. I’m currently working at home and they’ve just closed all schools and kindergardens…

Like @dialfonzo posted they are not that different from the Phoenix @xan (I’ve just replaced one defect servo, guess which one). I think our first goal is to make the hex work properly and have some options for different remote control systems. Then play with different designs. I do have some ideas myself, involving two extra servos and reduction gears.
@kurte a buzzer is really convenient, nice work! Your correct, I’m using FP math on the T3.6.
I’m not sure if we will ever agree on one (remote) control only. Like mentioned above there are reasons for why standard RC remotes are used for combat robots, reliability and accuracy. Then again that can be obtained through other DIY systems. The ArbotiX controller Kurt mentioned is very simple and might be good enough for many. Using high quality gimbals is a must though. Personally I really dislike the old PS2 controller when it comes to precision (data read from the gimbals). The RB-Dfr-223 sure looks like an interesting option, for some.
Personally I prefer getting data back from the robot too, like battery status and commando confirmation.

The software I’m using on this remote are based on the software used on the ArbotiX. I’m sure it could be improved a lot. The display I’m using (a very cheap Nokia display also has some limits when it comes to update speed). Currently I’m sending data at around 100Hz. The main loop on the robot also runs around that speed. So it’s pretty smooth. I could post a video explaining and demonstrating how I operate it, if interested.

kurte · March 15, 2020, 2:28pm

Hi @zenta and all - Hope you are all doing well. We are hanging in there. We saw some of this coming and stocked up and pretty much self isolating. Will be interesting to play with the new stuff, but it will probably be several days after I receive it that I will feel safe enough to open box and then probably again try to disinfect everything before touching anything without gloves… Yesterday I did pick up my first board from OSHPark that has connectors for LSS and Dynamixel servos… They are probably pretty safe now as with gloves, I opened envelope and took the three cards out and put into zip lock and through away the rest, and then added rubbing alcohol and let it sit in it for probably about an hour…

In the next few days will see how much of the board I have parts for…

Remotes: As you mentioned it may be difficult to come up with a single control that makes everyone happy. Yours looks great. I still have a similar version around here somewhere, although not nearly as refined as yours. For me ones like the Arbotix one was sufficient for most things I did as I am not coordinated enough to handle that many controls anyway

Wondering about your bi-directional communications with yours. I know that earlier I had issues with XBees where they would not consistently and reliably change communication directions and at times there could be long gaps of time where nothing is received… I believe over at Trossen, that @jwatte also had issues with XBess as well and converted over to different wireless setup, maybe something like two RF95s or??? Where he had two pairs on both the remote and the robot, one for each direction? Again not sure if this would be a direction RobotShop might want to go?

As mentioned the RB-Dfr-… may well for most. Over the next couple of days, I may try to play with the Teensy and Bluetooth stuff again and verify if my PS4 is still working. If not I have several different PS3s… While waiting I will probably try some of it out using the Dynamixels.

Again hoping everyone is doing well and staying safe!

dialfonzo · March 17, 2020, 12:49pm

@kurte - Nice PCB and i would not worry too much about the virus after your dip in alcohol.

I’m looking to cut the center plates very soon, to get the initial hardware out of the way.
I really like the legs that look more “insect like” but they leg design that i came up with is using all of the standard SES brackets which is a big plus from a company standpoint. (sorry…)

Everyone is open to do it the way they like even more if the code adapt easily to different shapes (dimensions).

Features:

BotBoarduino mounting pattern
Raspberry Pi / LSS-Adapter mounting pattern
Slot for hook & loop

Here are 3 stance (low / mid / high)

Here some “dimensions” that might help

If you don’t have any changes to ask, i’m going to produce those for you guys.
Will you require a basic assembly guide for this ?

All the best,

zenta · March 17, 2020, 3:11pm

Your configuration will work just fine @dialfonzo I don’t see any need for further assembly guide your pics speak for them self. I Assume you are using an idle horn instead of four nuts when assembling the coxa using the C-bracket and the other servo bracket?

zenta · March 17, 2020, 3:21pm

Nice finish on the OSHPark board @kurte! Good to hear you are safe (extremely safe IMHO) :-).
About the remote, I still have issues with the bidirectional communication. I thought it was bad coding from my side. I’ve not had time to figure it out though. Sometimes I loose data from the robot and I don’t get the status I want.

dialfonzo · March 17, 2020, 3:44pm

Yes - It make assembly much easier that way.

dialfonzo · March 17, 2020, 4:09pm

For the ones not familiar with it, we created a “cable clip” that can be mounted on the new generation of SES brackets.
Those are handy to run the cables as well as equipped with magnets.

As i was adding the clips to the legs, i added some clip positioning on the center frame as well.