Bullion Test Demo is an Android app developed by Timmy Brolin in the Utilities & Tools category. It offers a cheap and easy way to detect fake bullion coins by examining their resonance frequencies. The app utilizes a resonance test, also known as a "ring test" or "ping test," to determine the authenticity of silver coins based on their shape and material.

Unlike manual ring tests, Bullion Test Demo does not require users to know the exact sound of each coin. It can also detect resonance frequencies that are beyond the range of human hearing. The app provides support for three types of coins in the free version, with the option to purchase the full version for access to a wider range of supported coins.

To use the app, users should perform the test in a quiet room to minimize interference. They can select the type of bullion coin to test from a drop-down list and tap the microphone button to start the test. Blue lines indicate the expected resonance frequencies of the selected coin. Users should balance the coin on their finger near the smartphone's microphone and tap the coin with their fingernail or a hard object. The app will then analyze the sound and provide feedback.

If the sound matches the expected resonance frequencies, a green check-mark will be displayed. If there is too much noise or the sound does not match the expected frequencies, a red cross will appear. Some Android devices may have limitations in recording high frequencies, and the app will indicate this if it detects two out of three expected frequencies.

It is important to note that Bullion Test Demo does not guarantee the accuracy of its results. False positives and false negatives may occur due to various factors. The app should be used as a complement to other testing methods, not as a replacement.