Birth of Poppy Ergo Jr and support for low-cost XL-320 motors

[juju]

Changing the latency time make things better,

in :  %timeit dxl_io.get_present_position((1, 2, 3, 4))
out : 100 loops, best of 3: 6.91 ms per loop

but is only part of the problem.

I realise that changing the time for movement doesn’t change the goal_speed

poppy.m4.goto_position(130,1,wait=True)
poppy.m4.goto_position(0,1,wait=True)
poppy.m4.goal_speed

Out : 89.244

Faster :

poppy.m4.goto_position(130,0.5,wait=True)
poppy.m4.goto_position(0,0.5,wait=True)
poppy.m4.goal_speed

Out : 89.244

[juju]

I have an electronic beginner question about the molex connector :
Here it is the schematic of the molex connector for dynamixel servo in circuitmaker :

Here it is the real connector : http://www.molex.com/pdm_docs/adobe3D/22-03-5035.pdf

How can I know where is the pin number 1 of the schematic on the real connector ?
I try to have a look on the datasheet http://www.molex.com/pdm_docs/sd/022035035_sd.pdf but found nothing about a numerotation of the pin ? Also try to find out something on circuitmaker with the link between real and schematic but didn’t success

[Nicolas]

you can find pin number and robotis pinout on the XL320 datasheet. This is not perfect but at the bottom you have a small pictures with pin number :

http://support.robotis.com/en/product/dynamixel/xl-320.htm

We have a really new board called pixl that should interest you :

http://workspace.circuitmaker.com/Projects/78A4FE38-92CD-4DAB-9B5A-15E9EAD0FAC1

[juju]

Ok thanks for the pin number.

I had a look on the RPI pixl board and I wonder what is the purpose of this board ?

[Nicolas]

This board is dedicated to XL320 with RPI.

You just have to plug it on the RPI with the header on the left, a DC power source 7v on the DC Jack, and the XL320 chain.

This board convert Motor tension to RPI tension and drive XL320 network from RPI UART. This board is all you need if you have ergo JR and RPI… We are planning to produce it soon with génération robot…
If you need it now this version pass all our tests, you can produce it by yourcelf.

[juju]

@Nicolas

you can produce it by yourcelf.

Sure I’m interested, can you just help me a little. In the release (circuitmaker) there are a lot of files !
RPI shield poppy_78A4FE38-92CD-4DAB-9B5A-15E9EAD0FAC1-1.A.5.zip (1.8 MB)
Which are the files I need to produce the board with circuit hub ?

I just had a look on circuithub and it is expensive for only one board (200$). Other possibilities ?

[Nicolas]

If you need to use circuithub, I do it for you, but in deed for only one board this solution is really expensive :
https://circuithub.com/projects/Poppy_project/RPI-shield-poppy.A.5

An other way is to produce PCB with PCBpool or something like that, buy all needed components on farnell, and mount it and solder it by yourself (you will need some soldering advanced skills…)

An other other way is to wait a little bit the first production bash of Génération robot to split the price with many other poppy friends!

[juju]

Ok, I can wait few days
To plug motors on my usb2dynamixel (xl-320, AX or MX) I did this :

First time for me to design a board, very simple anyway but I hope there isn’t any mistake…
http://workspace.circuitmaker.com/Projects/272A238F-570E-4234-8395-431BFE9FDE25

[Nicolas]

I don’t see any mistake on your design. You just have to release it and estimate the price on circuithub!

[juju]

With eurocircuit, I have warning about size of the ring for the RPI shield :

Is it a real problem ? I also have a lot of design rules warning in circuit maker about the solder mask

@titwin Has the RPI shield ever been produced ?

[Nicolas]

This is relative to the producer tooling, eurocircuit seems to have small performance compared to some others.
This is interesting you sould change all via size in the original design I don’t think you can pull request on CircuitMaker. We just send a production to CircuitHb and there is no problem at the moment…

[juju]

I understand better what you mean by advanced soldering skill

Have you tested the board you ordered ? Does it works correctly ? And last question, I would like to use this board in an educational way, is there any documentation to describe how it works ?

[Nicolas]

This component is not the hardest one… look at the TPS54427DDAR, he has a really tricky pad…

We have a small problem with our ordered board, we had a reference worries with 3 resistors, we have to change them in all our boards.
We need to test them in hard condition, after that we will introduce it officially with some documentation, of course!