A small update on my InMoov build

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GroG's picture

Great update Mats .. I'm

Great update Mats .. I'm really excited about the connectivity between the 2 RasPi(s)..

It needs refactoring, but have you connected 2 instances before ?  Is this how you plan to operate it ?

Distributed Processing is so cool !

Mats's picture

Distributed processing

Yes Grog.

I tested connecting two instances before. It's more than a year ago, and it was a success. I didn't test all services and all methods at that time. I was just happy to see that it really was supported by the framework. http://myrobotlab.org/content/headless-head

So now it's time to start testing distributed processing for real. I guess that some things may fail, but thats's OK. I'm in this project to learn, and to contriibute to the development of InMoov and MRL.

I have had some problems connecting to my WiFi network because of the distance between my router and the PI's. But I will work that out. I also currently have some problems with connecting the PI camera to the Raspberry PI 3. I know that both the camera and the PI are worky, so it's probably a software problem.  

All the servos in the body and head are connected now. I just need to get  WiFi worky and make a demo script to show it. Currently working on putting a servodriver in the right arm. Left arm and hand are in for a major redesign so that the sensors will fit.  

hairygael's picture

Very great progress Mats! I

Very great progress Mats! I like the disposition of your hardware in the back.

Mats's picture

Distributed processing

All of my problems with the PI3 was because of a to small power supply. The camera and USB ports are worky again. The WiFi problem is probably bacause I was at a to long distance from the router. I have moved to a location closer to it and now it works fine. Right arm is also worky now with a servodriver in the lower arm. It drives the 5 fingers, the wrist and the biceps. 

So I moved on to testing distributed processing. I wrote a little about my tests about a year ago and was realy impressed with how easy it was to use. You can find that blog entry here: http://myrobotlab.org/content/headless-head

Continuing my tests, I tried to start an Arduino service, on the host where the listener is. The Arduino was started before the RemoteAdapter. And I hit a problem with serialization. I have sent a no-worky. The problem has to do with serialization of the Arduino service, since it uses DeviceMapping.

23:40:48.685 [HeadRpi] ERROR c.m.f.Service [Service.java:2131] HeadRpi error NotSerializableException - org.myrobotlab.service.data.DeviceMapping java.io.NotSerializableException: org.myrobotlab.service.data.DeviceMapping

In DeviceMapping I find this comment:

// transient too help prevent infinite recursion in gson 
// encoding since Arduino will have a reference
// to itself as a device
transient DeviceControl device;
I think this is the part that prevents serialization, but if it's not transient then gson will run into a loop when it tries to serialize the Arduino service. I think that I have hit the same problem in other services too where I had to mark some part transient to prevent this loop. 
I'm not sure how to resolve this conflict. Any ideas ? Newer version of gson perhaps ? The current version 2.2.4 is from 2013-05-13 and the latest release is 2.7 from 2016-06-14. Worth a try ?


Mats's picture

gson 2.7

I tested using gson 2.7 but tha't didn't solve the problem. If I remove transient from Devicemapping I get an infinite loop even with version 2.7 of gson.

Reading about alternate soltions here, but I want to discuss pros and cons before making any changes.