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Frequently Asked Questions

What parts do I need to build an AR4 robot?

There are 4 groups of parts needed to build the robot:

Why does the robot use a teensy 4.1 board and an Arduino Nano board?

The reason for this is that the Teensy 4.1 board has just enough pins available for the robot arm drivers and encoders.  The Teensy 4.1 board also operates at 600mhz which is needed for the robot arm kinematics.  Controlling peripheral devices such as solenoid valves and small 180° servos doesn't require the speed of the Teensy 4.1 and is instead done using either an Arduino Nano or Arduino Mega.  Solenoids and servos for these applications typically operate at 5v - the Nano and Mega are 5v boards whereas the Teensy operates at 3.3v.  The teensy is ideal for controlling the robot and the Nano / Mega boards are better suited for peripheral devices.  The control software is setup to talk to both boards simultaneously so the software can control the robot arm and control robot grippers and peripheral devices in unison. 

Can I buy the motors and drivers from Annin Robotics?

I have considered selling the motors and drivers along with the primary robot kit but this would add a great deal of cost to the project.  I would have to add the additional shipping, taxes and tariff costs, the primary goal of this project is to provide the lowest cost robot possible.  I believe purchasing the motors and drivers factory direct from Stepperonline is the best option and keeps the cost as low as possible for everyone.

Can I buy the robot fully assembled?

The answer to this question is similar to the previous question - I have considered selling fully assembled robots, The labor to assemble the robot does add a considerable amount of cost, the goal in this robot project has always been to create the lowest cost robot possible.  The vast majority of robot enthusiasts, students and small business owners utilizing the AR4 robot need to keep their costs at a minimum, and I have also found that having first hand experience building the robot gives everyone a really good foundation in knowing how it works, how it is wired and how to troubleshoot issues.  For these reasons and in the interest of keeping this robot a shared source and affordable robot, for now the project is only available as a kit where everyone can build their own robot for the lowest price possible. 

Are the AR3 and AR4 robots on Ali Express sold by Annin Robotics?

No, these are illegal counterfeits that violates the projects goals and the projects terms of use.  I get a great many complaints on these. They are cheap counterfeits that have a number of issues including inability to run the latest software – open loop encoders, poor driver performance – torque power and the gearboxes have backlash issues as they are not the same precision gearboxes from Stepperonline.  more info here

Where can I find the specification on the robot including its reach?

Chapter 6 in the robot build manual contains the robot specifications.  The robot build manual can be found on the downloads page under the AR4 downloads.

I don’t have a 3D printer – can I buy the covers and spacers?

There are several online retailers that can offer printing services but I have founds they can be expensive and that it is cheaper to purchase a 3D printer and filament for all the covers and spacers.   I use an Anycubic MegaS printer which I paid $229 for on Amazon.  I like this printer due to the fact it comes mostly assembled and all that is needed it to attach the head rail and plug in the motors and controller.  It also has a glass bed as well as dual elevation Z height screws and dual bed rails.  The only real challenge that I have found with 3D printing is getting the first layer to stick but I have had really good luck just calibrating the bed height using a sheet of paper, I just start a print and then shut off the printer when its starting the first layer and then manually drag the nozzle to each corner of the bed and adjust the bed leveling screws so that the piece of paper has just a little friction between the nozzle and the bed.  Then I power it back on and start the print again. You can also use an elmer's glue stick to put a very thin layer of glue on the bed which helps if you have issues but typically the PETG filament does fine on just the glass bed.  I use the free Cura slicing software which is pretty easy to open the STL and then set the bed / nozzle temps as well as the speeds, then all you do is export the Cura gcode file to an SD card, plug it into the printer and print the file.  Having a 3D printer has been the most valuable tool in my tool box given all the parts from grabcad or thingiverse you can print and being able to model something up and make a real part in a matter of hours.  I highly recommend everyone have a 3D printer.


What grippers can I use for the AR4 robot and how do I control them?

The robot build manual shows 2 different gripper options however you can attach any gripper you choose to the robot.  The manual shows using a SMC MHF2-8D pneumatic gripper, and there is also a servo gripper design shown in the manual. This video has some additional info on the servo gripper design  If you look at chapter 5 on robot grippers there is more information on both of these grippers.  Also this video on youtube goes through all the details on wiring and controlling grippers for the AR4 robot

Can I build and sell the AR4 robot?

I have a large number of people inquiring about using the Annin Robotics design for automation and reselling.  The intention of the project was a user build DIY platform that is completely free for primarily educational purposes but also for the hobby community and for individuals automating their own businesses.  The only requirement is that I have asked people not build the robot or manufacture robot parts strictly to resell for profiteering off the project.  I maintain that Annin Robotics designs and software remain free.  However If you would like to use the Annin Robotics design within the scope of automating a process and your are selling that process, and the robot only supports that that automated process I would not want to inhibit anyone’s efforts or development,  If that is the case, all I ask is that the aluminum and hardware components be purchased through the Annin Robotics website to satisfy the license.  Please contact me if you would like to use the AR4 as part of your automation design.  Please note that I do not permit selling the robot by itself but only as part of an automation process.

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