Can You Use a Smartphone Spectrometer for Scientific Purposes?

When it comes to the concept of using a mobile phone to perform spectrometry, the answer is a nuanced one. While the hardware digital signal processing (DSP) within your average mobile phone can be manipulated to some extent, it is not ideal for sophisticated scientific analysis. Let's explore what you can and cannot do with a mobile phone spectrometer.

Understanding the Limits of Mobile Phone Spectrometry

The radio frequency (RF) hardware in cell phones is highly specialized and limited to specific frequency bands. These bands are used for tasks like making audio text messages, internet communications, and other vital functions. In theory, with the right DSP configuration, a phone could be modified to display a spectral display of the received electromagnetic radiation. Each band that the hardware supports might be tunable, but whether this can be done and whether the phone allows access to this data is highly dependent on the model and the manufacturer’s policies.

Challenges in Utilizing Mobile Phone Spectrometry

The calibration of a mobile phone is far from that of an instrument. While there is some calibration for everyday use, it is much simpler and lacks the necessary precision for accurate scientific measurements. Moreover, there are no specifications for measurement uncertainty, rendering the data from a mobile phone spectrometer less reliable for scientific purposes. Given these factors, a mobile phone cannot be considered a true spectrum analyzer. Instead, it might be better described as a spectrum monitor, which is a tool that provides relative and not absolute measurements.

Examples of Spectrometers in Mobile Phones

Some Android phones already come equipped with a feature that displays the relative strength of different WiFi access points in a spectrum-like display. While this functionality is useful for network management, it is not the same as a scientific spectrometer.

Exploring Different Types of Mobile Spectrometers

There are various types of spectrometers designed for different applications, and it turns out that some of them are already integrated into your mobile phone in one form or another.

RF Spectrometers

A radio receiver in a mobile phone can be considered a spectrometer for a few channels of radio waves. Many phones come with Bluetooth, Wi-Fi, GPS, and 3G receivers, effectively making them multi-channel RF spectrometers, albeit with limited functionality.

Optical Spectrometers

Mobile phone cameras can be considered a type of spectrometer, especially when capturing visible light. Advanced camera models often have multiple sensors to capture red, green, and blue light, effectively making them three-channel spectrometers. Some smartphones even have secondary sensors that can capture infrared light, extending their capabilities.

Passive Infrared Spectrometers

A passive infrared spectrometer could be used to determine the temperature of a surface. These devices work by detecting the emitted infrared radiation. While they are not as common in mobile phones, they can be useful for thermometry and non-invasive temperature measurements. The principles behind these spectrometers are similar to those of camera technology, making them feasible additions to mobile devices.

Actively Driven Spectrometers

Other types of spectrometers carry their own source of radiation and measure how well it is transmitted through materials. These spectrometers are commonly used to identify the purity of materials and compounds. While these could be theoretically built into a mobile phone, the complexity and the need for calibration would make them challenging to implement with sufficient accuracy.

Conclusion

In summary, while the RF hardware in a mobile phone can be modified to a limited extent to perform spectral displays, it is not designed for scientific accuracy and lacks the necessary calibration. Mobile phone spectrometers, whether RF, optical, or passive infrared, have their place in user convenience and simple measurements but are not suitable for sophisticated scientific analysis. If you need reliable and accurate data, traditional scientific instruments remain the standard.