mBlock "send mBot's message" - how to use it?



in mBlock 2.2.1 there are the following building blocks for mBot:

  • send mBot’s Message ( )
  • mBot’s Message received

How do they work? I’m trying to send messages from one mBot to another but it’s not working.
I can’t find any documentation.

Can anybody help?


no answer from the Makeblock team?

Many thanks in advance.


Hello mump,

no reply so far…
Do you have any experience with these commands?


I’ve spent some time fiddling with it with no success. I have two mBots, one running an mBot send message block with the value 1 and the other running the code below. I get a compilation error (see stack trace afterwards). I suspect that it’s just not fully implemented because there doesn’t seem to be any instructions for using it in the Scratch-based environment. For what it’s worth, I also tried casting the 1 to a string but got the same compilation error.

Stack trace:

StackTrace.zip (1.7 KB)

I’ve got a teaching application in mind for using the IR Sensors to send messages between the mBots, but I’m having to shelve it for now due to this issue.


Did some more mucking about with this today. Ended up in the Arduino IDE so I could track the behavior in the serial monitor. What appears to be happening is that the IR receiver on one mBot is not seeing the IR transmitter on the other mBot. Progress, I guess, but not what I was hoping for. I’m wondering if the support team can provide any insight?


I’m interested too in this topic… any news?


I have some code I was working on that was to test out a sender and receiver via IR but It was so flaky that I stopped working on it. This was a few months ago so maybe a subsequent release has addressed the issues but I doubt it.
message_sender_led.sb2 (73.5 KB)message_receiver2.sb2 (73.8 KB)


if you are still wondering, here is a page that explains it,


Im working with the linefollower array you can find my code here: https://github.com/Tauvic/Technology-at-school/tree/master/Robots/Makeblock/develop