Distance measurement

A place to discus the development of leJOS for the EV3. Please do not use this section to post questions about how to use leJOS or to report problems etc.
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Location: Poland

Distance measurement

Postby Jeremy1980 » Sun Jun 19, 2016 11:02 am

Loading system:
  • Orignal firmware: FAST
  • ev3dev: GOOD
  • leJOS: SLOW
Initiate to run program:
  • Orignal firmware: FAST
Bluetooth support:
  • ev3dev: Bluetooth 4.0/BLE
  • Orginal firmware: 2.1
  • leJOS: 2.1
  • ev3dev: a fully fledged debian based firmware
  • LeJOS: tiny Java Virtual Machine that supports Java - extend original firmware
Support HitTechnic MINDSTORMS® Sensors: Can be better.
Support mindsensors.com products: Can be better.

IDE support:
  • leJOS: Eclipse plugin
  • ev3dev: Not found in Eclipse Marketplace
  • Orginal firmware: EV3-G ,LabVIEW for LEGO MINDSTORMS ,LabVIEW for Education

At last read about Nine alternative programming languages for LEGO MINDSTORMS
Last edited by Jeremy1980 on Sun Jun 19, 2016 8:24 pm, edited 1 time in total.

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Location: UK

Re: Distance measurement

Postby gloomyandy » Sun Jun 19, 2016 4:20 pm

and your point is? What do you intend to do about any of these things that you seem to think are a problem?

Most of the slow start issues are down to how long it takes to run a standard Oracle JVM on the EV3 hardware. But if you want to run a good VM then you really have very little choice. The alternatives are simply not very good. But feel free to try them.

Yes leJOS only supports Java, that is the entire aim of the project. Not only that but we have deliberately made a point of doing as much as we possibly can in Java rather then using alternate programming languages. Why? So that people familiar with Java can understand and have access to as much of the system as is possible. Projects like ev3dev have different aims and require different skill sets to work on them. So for instance have you considered what is required to add say support for a new hardware device from someone like Mindsensors? With leJOS it is a pretty easy job for most Java programmers just using leJOS. With ev3dev you need to be familiar with Linux kernel programming and have access to a rather complex build system. You also then need to test that support for the various different language bindings that exist (at least you do if you are doing the job properly).

As to support for Mindsensor devices (and other hardware vendors), it basically comes down to access to the hardware and an interest in using the device. The drivers that exist do so because one or more current or previous developers have access to the device. Most of the time this is because the developer spent their own cash on buying the hardware. Sometimes we have been lucky enough for the vendor to supply a device free of charge, but this does not happen that often. So if you have that hardware and are prepared to create a driver that follows the leJOS model then please do so. But please also be prepared to support people that try to use it in both the current and future versions of leJOS.
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