Entry-level oscilloscopes serve as an excellent gateway into the world of electronics, providing low-cost instrumentation for those setting up test benches, whether in a home garage lab or a classroom environment. However, the affordability of these tools often comes at a cost; the cheapest models are typically less capable due to limited features and lower performance standards. While these instruments can perform adequately for basic tasks, they frequently fall short when compared to more advanced equipment available on the market. Fortunately, limitations dont have to remain permanent. With a bit of ingenuity, its possible to enhance these simple oscilloscopes to incorporate advanced functionalities. An impressive project undertaken by a young innovator named Tommy illustrates one effective approach to transforming these budget-friendly devices into more capable tools.

The primary challenge with lower-cost oscilloscopes lies in their reduced precision. This is largely due to the fewer bits available for analog-to-digital conversion, which directly impacts the quality of the measurements. Additionally, these oscilloscopes tend to exhibit a high level of noise, which further diminishes their performance. Tommy has chosen to focus his efforts on the DSO138-mini, an oscilloscope that boasts a bandwidth of 100 kHz and an effective resolution of 10 bits. The transformation begins with the addition of an anti-aliasing filter to the devices input. This type of filter, functioning as a low-pass filter, is essential as it removes high-frequency components of the signal that can create complications, particularly given the devices limited resolution.

Once the anti-aliasing filter is in place, the next step involves performing digital post-processing on the oscilloscopes output. This processing serves to eliminate noise generated by the systems power supply, among other sources, effectively acting as a second low-pass filter. By employing these two methods, Tommy demonstrates a significant improvement in the oscilloscopes output, corroborated by experimental data in Part 2 of his project. The results reveal that a substantial portion of the noise present in the test signal has been successfully filtered out. What makes this achievement even more remarkable is that the only additional expense beyond the purchase of the inexpensive oscilloscope itself is for a ceramic capacitor, which costs around a dollar. To add to the excitement, Tommy is not a seasoned engineer but a junior in high school, showcasing the potential of youthful creativity and determination.

These innovative techniques could also be applicable to other budget-friendly equipment, including even cheaper oscilloscopes that are based on the ESP32 platform. Tommys project not only highlights the possibilities for enhancing entry-level oscilloscopes but also inspires others to explore and experiment with their own electronic tools to unlock new levels of performance without breaking the bank.