CT-1 Controller Details

FAQs

Q: What does it means "Virtual" range limits?

• The Range Limits are virtual, and based on motor steps counting and are NOT based on any external physical limit switches. You need to be aware that if you are planning any maintenance to the antenna or make any changes to the motor position, you MUST adjust the range limits again. Avoiding that can damage the capacitor!

Q: Why ESP8266-12E?

• Easy to use, tiny, cost-effective controller. In addition, provides the option to add more features in the future and perform tests and experiments. That's the reason that I added two extra sockets, in parallel to the ESP.

Q: Why DRV8825 and not A4988?

• Although both driver motors are almost the same, the A4988 can be set to up to 1/16 steps while the DRV8825 can be set to 1/32, that can help us with more accurate tuning. In addition, the DRV8825 can handle more current.

Q: Are you selling stepper motors as well?

• No. I'm focused only on the controller. It can support lots of different of Nema Bi-Polar motors and you have the freedom to choose one that is best for your own application.
  For example, this is the motor that I'm using and you saw on the video.

Q: Which type of stepper motors are supported?

• Most of the Bi-Polar Nema stepper motors will work. 

Q: What is the type of the motor connector?

• The Female connector that on the PCB is the M2501R-K-04P, and the Male connector that can fit is the HX2.54 (4 Pin to 6 Pin). 

Q: What is the allowed Max input voltage?

• Max input is 18V as there are two parts that have voltage limits:
  AMS1117 (Voltage Regulator) - Max voltage that allowed is 30V, even though the recommended Max is 18V.
  DRV8825 (Motor Driver) - 8.2V to 45V (2.5A at 24V).
  
  The final decision about the input voltage should be considered the Stepper motor specifications as well.
  

Q: Why the controller only supports WiFi 2.4GHz networks?

• The controller supports only 2.4GHz networks as this is a limitation of the ESP8266 controller itself.

Q: After configuring my WiFi AP and credentials nothing happened, what’s wrong?

• Try to reboot the ESP.

Q: I see weird characters on the serial monitor, what’s wrong?

• It’s probably the connection Baud rate speed of the Serial Monitor, that should be set to 115200.

Q: What is the use of the DIP Switches?

• The DIP Switches, when "ON", provide 5V to the DRV8825 ports M0/M1/M2. These ports configures the motor driver micro-steps. When all are "ON", it set the max of 1/32 micro-steps. 

Q: I see two blue LEDs on the controller, what do they mean?

• The one that is on the board is the Power LED. The other located on the ESP8266 itself and it will blink any time the controller sends commands to the motor driver.

Q: What if I need to replace the DRV8825?

• No problem, it's as simple as swapping the current one with a new one. But, the new driver will need to be calibrated with the current limit that fits the motor current.
  In short, for example, if the Max motor current is 1.5A, the reference voltage (VREF) on the motor driver will need to be half, and in this case 0.75V. You can measure that voltage between the "GND" pin and the tiny potentiometer that is located on the DRV8825.
  A full detailed process can be found here.  
  Before performing the calibration process, make sure to disconnect the motor.

Q: Are you selling a case?

• No case at this time because this controller can be used for so many applications. This way everyone can add this controller to any creativity project.
  

Q: Are you selling a whole magnetic loop antenna?

• Thanks for trusting my design, but I'm not ready for that yet. It's a big logistic step for me. If something changes, I will announce that.

Warnings

• Before connecting/disconnecting the stepper motor to/from the controller, make sure that the controller is without power.

If you can't find an answer for your question, please use the Contact form to submit your question. I will reply to you with the answer and if needed, I will add the question to this page. Thank you.