User Manual/2. Setting up the system

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Congratulations! If you got here it’s because you have already gathered together all the parts needed to build your motion capture suit. Now is the moment of truth.

In this chapter we will put everything in place and see if it's working correctly. We should check the following functionalities:

The crossed-out functionalities require some tweaking. They will be available soon.. See the Roadmap to get an idea of the state of the development
  • The SBC boots correctly.
  • The SBC acts as an access point, and we are able to connect to it from a separate PC.
  • The Utility software on the SBC is working correctly.
  • The Hub and K-Ceptors are wired correctly and the Notochord is able to talk to them.

Hardware setup[edit]

Powering the system[edit]

10400mAh Power bank and Raspberry Pi

To power the system a 5V, 2A supply is needed. It can be connected to the SCB only, or also to the Hub. Both connections use a micro USB-B connector. By far the easiest way to achieve it is to use a common power bank. It should be rated for at least 2A.To have a durable supply a capacity of at least 10000mAh is desirable. Under normal capture conditions such a power bank was able to keep the system running for around 8 hours.

The Chordata Hub has two possible configurations: with or without a separate power source. A jumper on the Hub (JP1) allows you to select between these configurations.

  • In the former the power comes from a buck converter on the Hub, that takes a 5V input and delivers 3.3V to the rest of the system.
  • In the latter the power comes from 3v3 rail on the SBC.


The Chordata system uses only a 3.3V tension. Don't apply 5V or higher voltages directly to any pin! Otherwise it can result on unrepairable damage.

A 5 volt tension can be applied only via the micro USB connectors on the Hub or SBC


Using the dedicated power source[edit]

This is the recommended configuration. The power line from the Powerbank should go to the micro USB connector on the Hub (J12), and from the big USB connector (J11) to the SBC.

To use this configuration the jumper should be positioned connecting the pins #1 and #2 of JP1


Using the 3v3 rail from the SBC[edit]

This configuration is mostly used for testing purpouses. The power line from the Powerbank should only go to the micro USB connector on the SBC.

To use this configuration the jumper should be positioned connecting the pins #2 and #3 of JP1

Wiring the Hub and raspberry[edit]

Start by wiring the hub and the raspberry using female jumper wires as described in the diagram. Then power the Raspberry. You should see a red led constantly on and a green led blinking, that means that the amount of power provided is enough to keep the Raspberry working, and also that the system is booting.

The blue led on the Hub should stay on as an indicator of a stable power supply.

Raspberry pi 3 and Chordata Hub wiring

the yellow 3v3 line is not used with the Dedicated power source configuration.

Connecting the K-Ceptors[edit]

Plug one of the ID Modules on top of one of the K-Ceptors, then plug it to one of the gates of the Hub.
Be sure to plug the cable on the IN --> connector of the K-Ceptor. Other K-Ceptors can be connected to the output of the previous one forming a chain, always going from OUT --> to IN -->.

On a working K-Ceptor the Blue led [D1] should turn on and stay that way.

K-Ceptor-wired.jpg

If you built the hardware yourself and want to know how to test and troubleshoot a K-Ceptor take a look at: Troubleshooting a K-Ceptor

Connecting to the WIFI LAN[edit]

The SBC acting as an access point feature requires some tweaking. It will be available soon. (See Roadmap)

In the meantime you can use an external access point as described in this section.


Use an external router or a smartphone hotspot to create a WIFI LAN with the following specs:

  • SSID: Chordata-net
  • Pass: chordata

The SBC will connect to it on boot.

Testing the system[edit]

In a near future, once the Utility software is up and running you will be able to access the system and test it in a much more easy way.

In the meantime you have to access to the SBC's terminal environment either by plugging a monitor and keyboard to it, or through SSH.

See the Roadmap to check the state of the development.

Run the notochord to test the Hub[edit]

On the SBC terminal environment navigate to the folder where the notochord binary is, and run it. Add the client computer IP ADDRESS as a parameter in order to receive the data.

cd notochord/bin
./notochord <CLIENT COMPUTER IP ADDRESS>

That will run the notochord using the default Chordata.xml configuration file, which by default reads only one K-Ceptor with a value of 1 from the J1 gate on the Hub.

The Chordata.xml file contains a description of the Hubs and K-Ceptors connected the SBC. The notochord uses this description in a process called Armature parsing to create an internal representation of the devices to be read, so it should match way the physical devices are connected.
You can learn more about how to describe this hierarchies here.


If you want to change the configuration file for the notochord use the -c flag. For example, to read a Default_Biped_Configuration you can issue:

./notochord -c ../default_byped.xml <CLIENT COMPUTER IP ADDRESS>

To use the file default_byped.xml which comes by default when downloading the notochord program.

If you get any errors there's probably an inconsistency between the configuration file and the way the physical nodes are set. It can also be due to a hardware problem, or a misconfiguration on the SBC. Take a look at the Troubleshooting section on the Notochord page