Creating a USB-C Passthrough with power charging detection

[stealthrt]

Hey all I have a project I am needing to do but I'm unsure as to the best way to go about doing it.

What I am wanting to do is check to see if a tablet or laptop is plugged into the USB-c cable so that I can have a visual representation of confirmation that it is connected correctly.

Most of the tablets I am using do not have any visible feature that showcases that its plugged in or not. But even if it did i would never be able to see it due to the tablets being close together.

This is what my setup I created looks like:


When your placing the tablet/laptop into the slots from the front it's difficult to tell if it made it into the connector or missed it.

So my idea was to create a PCB that has 6 female USB-C inputs and 6 female USB-C outputs. But I am not sure what I need to test on the pins to determine if its connected to something or not? I plan on using an arduino to check the voltage and see if it drops XX amount when something is plugged in but again, there may be a better way of checking it?

My PCB would look similar to this one but without the headers and holes and with more than one set: 

[HarryA]

See:  https://en.wikipedia.org/wiki/USB 

Be sure to look through the references at the end of the article.

[stealthrt]

So something like this?

[bidrohini]

Hi, have you completed this project yet?

[loribennms]

On 4/19/2023 at 6:41 AM, stealthrt said:

Hey all I have a project I am needing to do but I'm unsure as to the best way to go about doing it.

What I am wanting to do is check to see if a tablet or laptop is plugged into the USB-c cable so that I can have a visual representation of confirmation that it is connected correctly.

Most of the tablets I am using do not have any visible feature that showcases that its plugged in or not. But even if it did i would never be able to see it due to the tablets being close together.

This is what my setup I created looks like:


When your placing the tablet/laptop into the slots from the front it's difficult to tell if it made it into the connector or missed it.

So my idea was to create a PCB that has 6 female USB-C inputs and 6 female USB-C outputs. But I am not sure what I need to test on the pins to determine if its connected to something or not? I plan on using an arduino to check the voltage and see if it drops XX amount when something is plugged in but again, there may be a better way of checking it?

My PCB would look similar to this one but without the headers and holes and with more than one set: 

acid staining tampa

Your project idea of creating a PCB with multiple USB-C inputs and outputs to visually confirm if a tablet or laptop is properly connected sounds interesting. To determine if a device is connected to the USB-C cable, you can use a combination of voltage sensing and communication protocols. Here are a few suggestions:

1. Voltage Sensing: As you mentioned, you can use an Arduino to monitor the voltage drop across the USB-C pins when a device is connected. The USB-C connector uses specific voltage levels, such as 5V or 20V, for charging or data transfer. By measuring the voltage levels, you can determine if a device is properly connected or not. However, it's essential to refer to the USB-C specification and understand the specific pin assignments and voltage levels for your project.

2. USB PD (Power Delivery) Protocol: USB PD is a communication protocol used in USB-C connections to negotiate power requirements and capabilities between devices. By utilizing USB PD communication, you can establish a handshake with the connected device and receive confirmation signals or information about the power status. This method provides more reliable and accurate detection of device connection.

3. USB Data Communication: Another approach is to establish a basic USB data communication link with the connected device. You can use the Arduino or a microcontroller to send and receive data over USB to confirm device connectivity. By implementing a simple communication protocol, you can exchange signals or information that indicate the successful connection of the device.

Consider combining the above approaches based on your project requirements and the capabilities of the devices you are connecting. It's important to refer to the USB-C specification, study the pin assignments, voltage levels, and communication protocols to ensure compatibility and accurate detection.

When designing your PCB, ensure proper isolation and protection circuits to prevent any potential damage to the connected devices. It may be beneficial to consult with an experienced electrical engineer or seek guidance from relevant online communities specialized in USB-C and electronics projects to ensure the best design practices and safety considerations.