Which board for a hexapod

Help & Support Robot Parts
1

Hi guys

I build on a hexapod, very similar in structure to the phoenix.
The hardware is finished and now comes the programming.

I wonder which board I should use.

I already have a bot board 2 and a basic micro arc32.

So as I understand the arc32 quite strong but apparently many of us currently switch to arduino.

I do not want to build on a “worn-out” board.
And I’ll certainly need the help of the community.

What do you think of botboarduino?

In the first step I need 18 servos.
According specifications are 18 servos can be used.

Do I still need a separate servo controller additionally?
If so, perhaps the ssc-32?

Do you have alternative suggestions for boards?

I like the idea to have the possibility to add shields to my bot.

Many thanks in advance

2

The BotBoarduino + SSC-32 could be used and has sample code; very little development needed:
lynxmotion.com/c-153-botboarduino.aspx
lynxmotion.com/p-395-ssc-32- … oller.aspx
lynxmotion.com/p-869-ps2-rob … er-v3.aspx
lynxmotion.com/images/html/build99f.htm

3

FIrst off the Arc32 is a great board, but as it is no longer sold, so because of this and the fact I prefer to program in C, I converted all of my hexapods to Arduino and … I used to have one of these on my Phoenix and it worked great and could do everything including drive the servos without a servo driver board.

Also what to use may depend on what type of servos you used. Did you use standard hobby servos like the Hitec HS645mg? Or something different like Robotis AX12?

The Botboarduino - is a Arduino Atmega 328 Duemilanove compatible board. The board is capable board to use on a hexapod, but you will need some form of servo driver like the SSC-32, and the current programs will fill use the complete capacity of the CPU… Yes the servo library on the arduino 328 can drive up to 16 servos, but you will most likely run into servos jittering if the board is doing anything else like reading from PS2 or Inputs and Outputs from serial port…

I have the Phoenix code base running on many different boards, so the choices are up to you. Most of the code for these are up on github:
github.com/kurte/…. There are lots of different threads up here that talk about these many choices.

Basic Atom Pros/Arc32 - The old stuff

Arduinos - I have tried it out on many different Arduino and Arduino compatible processors, including Mega, Due, Chipkit (Uno32, Max32).

Teensy 3.1 - This is what I am currently playing with. Great little boards (pjrc.com/store/teensy31.html), also sold now by Robotshop and I build my own adapters…

Linux boards: I have had it working on several different Linux boards including raspberry Pi, BeagleBone black, ODroid U2/U3.

Which is best? Good question, depends on what you wish to do, your experience… Arduinos are nice, lots of information around. Right now I am having a lot of fun with the Teensy. Linux boards have lots of power and are fun, but have a much higher learning curve.

Good luck
Kurt

4

Hi all!

Thanks for the answers.

I found so much more boards and controllers and it’s vers hard to decide!

I also already have the ssc-32 board. I bought a second hand board package before.

Arduino is nice because of the big community and there are a lot of examples for hexapods out there.
With the botboarduino I won’t have issues with the power supply. (Integrated Ubec !?)
I got two Lipo batteries to power up the boards.

Has anyone tried out this: learn.adafruit.com/16-channel-p … r/overview
But than i defently will run into power supply issues.
A power bank would solve but than the Lipos are redundant.

I would prefer coding python rather than c. (Python is more related to my job).
But there are no or very few examples for python hexapod inverse kinematic problems i guess.

I get more and more uncertain the longer I do research for boards.

:frowning:

5

And what about this little guy: mikronauts.com/raspberry-pi/robopi/

6

I have not done anything in Python, But I have seen others who have. I know for example that the two Hyland brothers (Jon and Dave) have ported Micropython to the Teensy 3.1 boards and have also built their own boards based a lot on the Teensy. forum.pjrc.com/threads/24794-Mic … Teensy-3-1

7

Finally: I will go for the Raspberry and the SSC-32.

I already have these two boards so i can start with kurts code.

Is there a wiring guide available for the boards?

Btw. Kurt - are you german?

8

FYI - I don’t like to give out too much personal information on boards like this, but I am American…

Wiring - I believe the code is setup on the Raspberry Pi project to use the same SSC-32 wiring as shown in the Lynxmotion tutorials, like: lynxmotion.com/images/html/build99f.htm

As for power, again depends on what servos you are using. On my T-Hex which has the RPI, I am using HS645mg servos, and I am using an LiFEP04 battery, which normal voltage is 6.4v which the servos don’t mind as it’s fully charged is about 7.2v which is about the same as the 6v NIMH battery. So I wire this directly to the VS of the SSC-32 (through switch). As for VL of SSC-32 up to you, could simply use battery voltage…

You need to supply +5v to RPI and maybe external USB powered hub. You need some form of BEC or the like that takes your battery voltage and converts it to 5v (or 5.1). Again depending on Battery look for ones that don’t require higher voltage… Example one that may work: robotshop.com/en/dimension-e … rkbec.html, but this one only supplies 1.25A. The one I have on one of mine cuts out as the battery gets lower… Also you need to wire this to an appropriate USB connector to power the RPI.

Also with RPI B (not B+), could not source a lot of current to on-board USB connectors, so you often needed an external USB powered HUB if you used some WIFI adapters and the like. I wired my T-Hex up with one. My powered hub was pretty dumb, so I connected the hub up to the RPI for signals, I powered the hub and then I connected a 2nd USB cable from Hub back to RPI (Power USB), to power the RPI. On many smarter usb hubs this does not work as the hub only powers up if signal coming… In which case you simply split the power from BEC…

You then need to connect RPI to SSC-32. I cheated and have prototype SSC-32U which has USB input, so I simply plugged a USB cable into it and the powered hub… Normal SSC-32, would use USB to serial adapter, plug into hub and then depending on type of adapter either plug into 9 pin connector or if breakout board connect up to TTL levels…

Kurt