Java API for Android Apps

[MattXB]

Hi Anders,

first of all, thank you and Lars for your extraordinary work! I am so excited to unleash the full potential of my new EV3.

Professionally I am working as a software developer for handheld and mobile devices. Our apps control real life devices using TCP and UDP based communication over a WiFi network. Therefore I read your guide “How To Establish A WiFi Connection With The EV3″ with great interest. You explained how to open a TCP socket on the EV3 using the original firmware. After that you showed an example of how to use the Monobrick Comm Lib to control the motors.

I would like to control my EV3 using my own android app, that means remote controlling the motors and also reading sensor values from the EV3. Since android extends java, I was wondering, if there is some Monobrick-like API for java?

If not, I was thinking of implementing one for my own and if that works publish and share it with the EV3 community.
Since you have already done the job for C# and have a lot of experience, I thought I’d ask you first, if that is a good idea and ask you about the possible limitations of this enterprise. So here some questions to you about that:

1. First of all, do you think it is a good idea to implement a Monobrick-like API for Java?

2. Do you have some documentation about the underlying TCP protocol that is used my the native EV3 firmware? I.e. what are the TCP packet / stream contents and their respective replies. Is it String-based or byte-based?

3. What are the limitations to the commands sent to and received from the EV3 via TCP using the native firmware?

4. Designing the Monobrick firmware on the EV3, have you added any TCP oder UDP based protocol that would allow for an extended control of the EV3?

Thanks in advance for your answer!

Best regards,
matt

[Anders Søborg]

Hi Matt

Thanks for visiting my site….

if there is some Monobrick-like API for java?

I don’t know to be honest – but I think the best place to ask this question is at the LeJOS forum/site!

Do you have some documentation about the underlying TCP protocol that is
used my the native EV3 firmware? I.e. what are the TCP packet / stream
contents and their respective replies. Is it String-based or byte-based?

It is byte-based. I think the past place to start is to look at the source
code of the standard EV3 firmware. It has some documentation that is very
usefull. You can find it here. Also you might have a look at the source code for MonoBrick.

What are the limitations to the commands sent to and received from the EV3
via TCP using the native firmware?

To many to list here – have a look at the source code.

Designing the Monobrick firmware on the EV3, have you added any TCP oder UDP
based protocol that would allow for an extended control of the EV3?

No – but I have added some extension that allows to send tunnel specific
commands. I think that the mailbox system is what you might be thinking off.
This allows you to send custom data back and forth between the PC and EV3.
However with MonoBrick you can only send custom data. It is nothing that
can’t be fixed but I haven’t yet had the time to fix it.

Anders

[Author]

Posts