I have built a drawing robot (Makelangelo) using Arduino Mega, Ramps 1.4 (2 nema steppers attached with A4988 drivers) and a servo. It is running Marlin firmware. The robot runs great. No problems. It is powered with 12v into ramps 1.4
However, I now am trying to add a reprap_discount_full_graphic_smart_controller. I have it fully working as well except if I unplug the computer.
If I unplug computer, it will reboot just before it should draw. If I unplug the servo it will draw so I think it is some power issue. However, I am a real idiot when it comes to power issues, so if anyone could explain what might be the problem and/or solution to me like I am 5 that would be appreciated!
Welcome! That sounds like a real fun project. I will take a SWAG and say it is a power problem. I think when you unplug you are removing the 5V or causing a drop on the other power source at the quick switching of an additional load.
Since we cannot see what you are using you can help us by posting your Annotated schematic, and be sure it includes all connections, grounds, power sources. The connections are very important as are the power sources. I do not think your software is needed at this point as it appears to trash when disconnecting/connecting the computer.
Thanks! Yeah I am almost certain it is a power thing. I have searched other threads and people get at that being a potential problem, but nothing I have found explains a solution that I can fully understand.
Not exactly sure what animated schematic would be. But would this be what you mean?
yes. you can connect 12V from RAMPS to Vin of Arduino. better of course is a dedicated step down converter.
why it is working without USB until stepper starts? pololu stepper driver modules can produce for self needs power from any possible source, and this power over 5V line is enough for needs of arduino and lcd, but when steppers are activated they drops voltage and entire system is without power. it disactivates the steppers and Arduino starts again, it looks like reset.
That is a mechanical diagram. Schematics are our map to designing, building, and troubleshooting circuits, ie the language of electronics. Understanding how to read and follow schematics is an important skill for any electronics engineer.
Sparkfun has a nice starter on reading schematics, Check this link: How to Read a Schematic - SparkFun Learn If you are serious there are many free CAD (Computer Aided Design) programs available from very expensive to free. I use KiCad and for me it takes me from concept to finished PCB.
