Thank you for your comment. I checked the link and you are right, it's the wrong link. I corrected the link on my website and it has the correct link now. Thanks again!

Mark Greco do not place lipo on top, noob . lipo is heavier part in this project. it should be in bottom

osman özütemiz I will build it exactly as Joop has done the project It is important for the battery to be on top for inertia

Osman, did you even watched the video? You need some inertia on the higher part of the robot to get it to work. Check this video on how to balance a stick on you finger: kzfaq.info/get/bejne/otGPg9qmnNTKYYk.html

Joop Brokking no, i dont know english im using translste

I also want to say the thorough information you provide is great! The bringup steps, checking for overcurrent, etc, are particularly good. These steps are important for any project but almost never discussed. Many folks that view this tutorial, even if they don't build the robot, will learn important concepts they can use on future projects.

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Thank you for writing me this comment. I really appreciate it!

Thank you for sharing and great to hear that you learned something!

Hi Skyreacher. Congratulations on getting your robot project working. I've been working on this project for about 4 months. I'm at the point where I've soldered the boards and I know that my DRV8825s work and are set to appropriate current for the motors. I'm able to drive the steppers via the 8825s on a separate arduino circuit, no problems. However I'm finding some strange things on the main circuit. On Joop's diagram, resistors R2 and R3 are connected. Does this not effectively short out the purple and black and gray wires on the diagram? I get about a short between the gray and purple connections for the 8825s(lower right two pins) even when the 8825s are not on the board.The low voltage (5V) side of the circuits seem fine, but the high voltage side just goes to full power and the motors are frozen when the power is on. Can you confirm that the -ve side of the battery feeds BOTH the ground pins on the 8825s AND the GND pin on the step-down transformer that gives me the 5V supply for the components and around the low voltage sides of the circuit boards?. I'm at the point where I'm thinking of starting again with the circuit soldering. Any insights you can offer are greatly appreciated. I'm really looking forward to completing this project as I'm on a robotics study group in my board of education in Ontario Canada, working to build our capacity in Arduino and robotics.

Hi Gordon! Search for "voltage divider" to understand what R2 and R3 are doing. This part of the circuit is completely OK, it does not create a short. The wire between R2 and R3 is connected to A0 on the Arduino - this is used for monitoring the battery. When the battery becomes weak, the robot will stop working without damaging the battery. Yes, ground is the same on the whole circuit. All the black and light grey lines on Joop's diagram are connected. It sounds like there's a problem with your lower right two pins of the stepper driver (where high power is feed to them). If you test your circuit, there should be no connection between them. Having a short there can be dangerous for your battery! I'd not connect the battery at all, as long as the problem is there. Check your board very carefully, there must be a soldering problem somewhere (a connection between the purple and the light grey/black lines).

Yes you can

Can you tell me which type of stepper motor (bipolar or unipolar) Joop have used?

hi sir may i ask about the rpoject?

I used A4988 stepper drivers. They need logic level 5V and at least 8V motor power. There are 3 pins to define step size (tied to +5V or GND to achieve 1/4 step). there is also one pin to be tied to 5V. Note that steppers have speed limitations. To fast clock will make buzz but not move. As a starter do not exceed 200Hz.