> For the complete documentation index, see [llms.txt](https://pekaway.gitbook.io/van-pi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://pekaway.gitbook.io/van-pi/connecting-devices/watersensors/resistance-ohm.md).

# Resistance (Ohm)

he VAN PI OS supports the use of resistance sensors, which operate by providing different resistance values based on the water level. To set up a resistance sensor, follow these steps:

1. **Connecting the Sensor**:
   * Connect the sensor to one of the input channels (1-4) and the GND (ground) pin on the VAN PI OS.
2. **Configuring the Sensor**:
   * Access the system's web interface.
   * Navigate to the settings for the input channels. (Config->Sensors) 
   * Set the desired channel pair to "Resistance" (you can only set channels pairwise: 1&2 or 3&4).
   * You can also change the Name for the sensors here. 
3. **Measuring Resistance**:
   * Once the channel is configured for resistance, the system measures the resistance using a voltage divider method.
   * This allows for accurate resistance readings by measuring the voltage at the channel pin
   * You can also check if you can measure 3.3V between the channel pin and ground. That confirms the voltage divider is activated. 
4. **Calibrating the Sensor**:
   * **Full/Empty Calibration**:
     * Fill the water tank to its maximum level and set this as the "Full" value in the web interface.
     * Empty the water tank completely and set this as the "Empty" value.
   * **Direct Resistance Value Setup**:
     * If you know the exact resistance values corresponding to the full and empty levels, you can directly enter these values for each channel in the web interface.

By following these steps, you can effectively integrate, configure, and calibrate resistance sensors with the VAN PI OS, ensuring precise water level monitoring for your application.

{% embed url="<https://www.canva.com/design/DAGF3B73MrU/MxJc8ouR8gUlaIS6_92h9w/view>" %}
Resistance Sensor to VAN PI CORE
{% endembed %}

{% embed url="<https://youtu.be/-CQt5fftAPw>" %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://pekaway.gitbook.io/van-pi/connecting-devices/watersensors/resistance-ohm.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.