Electronics¶
Coming into Fab Academy, I was basically knew nothing about electronics, programming, and such. The concept of input and output devices is something that I just heard the first time at the pre-FA bootcamp. What I knew at the start was.. for the final project, your project should have an input and output system, that’s it. So, my approach initially was by looking at many electronic components around me and learning from other people’s project to get some inspirations.
Electronics System Overview¶
Components¶
Initial Plan¶
Despite being somewhat unclear at the start, my goal for my final project was quite clear in some parts. I aimed to create an instrument device to measure various parameters of an aqueous solution. I know I will be using a bunch of sensors as my input devices. And for my output device, I know that I need to show the measurement results on the display. But I also thought of adding other output elements like LED indicator and/or buzzer for a better user experience. This was by far what was clear to me at that time. My initial electronics plan looks like this😅😃
19/02/2024
Input:
- Electrical conductivity
- pH
- Temperature
- H2 rich level (if possible)
- Total Dissolved Solids
- Toxic contaminants (?)
Output:
- OLED Display
- LED light/buzzer/speaker – for warning
Others:
- Battery: …
- MCU: …
- Buttons (?)
My understanding of a ‘system diagram’ was definitely off here… haha 😅 But I think what I was trying to describe was ‘what to program’—the function of my project—systematically by writing pseudocode for what I wanted the project to do. Not only that, this is how I envisioned the electronics development would be.
At the time, I still didn’t have a sense of how easy or hard it would be to program all these things. I had no idea how they would all connect and integrate with each other, let alone the specifications of each component.
Questions to be resolved:
- What MCU? MCU features and spec? Wireless?
- What power requirements and system? What power supply?
- How many pins needed?
Midterm-progress Plan¶
During the midterm review, I managed to get clearer and more specific with my intended electronic components. I dropped some sensors, particularly the one for measuring toxicity, because not many people had developed it. I planned to use the ESP32S3 as the MCU due to my intention to upload the data to the net. For navigation, I decided to use a rotary encoder because it is a versatile component and Eka had successfully programmed it before for the machine week. At this stage, I was considering using a commercial EC/TDS sensor by DFRobot, only to realize that the sensor itself cost around 80 USD.
Again, my understanding of a system diagram was still incorrect. I think I was actually attempting to make a block diagram here, which also wasn’t quite right. This diagram didn’t accurately represent either a system diagram or a block diagram 😅.
Questions to be resolved:
- What are the specifications and requirements of each components?
- How many pins needed to which pins in the MCU? Will there be enough pins?
- What power requirements? What are the voltage requirements of each component?
- What wirings and connectors?
Final Components¶
In the end, these are the components that I stick to use for my final project:
Input Devices
- NTC Thermistor 10K 3435
- Electric Conductivity + TDS Sensor (DIY) using 1k resistor resistor
- Rotary Encoder
- pH Sensor (further development)
Output devices
- OLED SH1106 12C 1.3”
MCU
- SeeedStudio Xiao RP2040
- Managed to get a frugal way of producing EC+TDS+Temperature sensor from a youtube tutorial referred by Rico
- Stick into using XIAO RP2040 because for whatever reason, when I tried to connect it to ESP32S3 / ESP32C3, it failed to generate any readings.. showing nan results
- Prepared pin connections for pH sensor.. but I didn;t have enough time to work with the pH sensor.. so I’ll continue developing that after Fab Academy
System Diagram¶
