rosserial [ERROR] lost sync with device, restarting ...

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Hello I am building a differential drive robot using differential_drive package and rosserial_tivac to interface with my hardware I have written my codes and iclude them all in one launch file when i use roslaunch every thing is working fine and the following message appear in terminal

process[rosout-1]: started with pid [11918]
started core service [/rosout]
process[serial_gate_node-2]: started with pid [11935]
process[lpid_velocity-3]: started with pid [11936]
process[rpid_velocity-4]: started with pid [11937]
process[twist_to_motors-5]: started with pid [11938]
[INFO] [1534898274.948213]: ROS Serial Python Node
[INFO] [1534898274.952975]: Connecting to /dev/ttyACM0 at 57600 baud
[INFO] [1534898274.997246]: /twist_to_motors started
[INFO] [1534898277.081039]: Note: publish buffer size is 512 bytes
[INFO] [1534898277.081769]: Setup publisher on lwheel [std_msgs/Int16]
[INFO] [1534898277.093732]: Setup publisher on rwheel [std_msgs/Int16]
[INFO] [1534898277.111318]: Note: subscribe buffer size is 512 bytes
[INFO] [1534898277.112105]: Setup subscriber on lmotor_cmd [std_msgs/Float32]
[INFO] [1534898277.126081]: Setup subscriber on rmotor_cmd [std_msgs/Float32]

Then when I try to publish a msg to the topic /twist that supposes to drive the robot. The motors start operating in the right direction but with a full speed which possibly means they didn't get the proper PWM value and I am getting the following info appearing on my terminal

[INFO] [1534898288.361617]: wrong checksum for topic id and msg
[ERROR] [1534898302.098102]: Lost sync with device, restarting...

the codes witch I am using is from this repository if any one can help please