# Careful Beige Lightcycle ## Description Driver drowsiness detection ECG front end based on the AD8232 with ECG electrode interface, analog signal conditioning, a dedicated 50 Hz twin-T notch filter for power-line interference rejection, regulated low-noise analog power, and a downstream conditioned ECG output prepared for processing and fatigue/drowsiness analysis. ## Project Details - **Owner:** bhumi233 - **Created:** 3/23/2026 - **Last Updated:** 3/24/2026 - **Visibility:** Public - **Design Notes:** Functional blocks: ECG electrode connector, input bias/protection, AD8232 analog front end, 50 Hz notch filter for mains rejection, output buffering/conditioning, low-noise 3.3V power regulation, and downstream ECG output for processing in a driver drowsiness detection system. - **Detailed Design Notes:** ECG driver drowsiness detector built around AD8232 front end, three-electrode RA/LA/RL interface, low-noise 3.3V analog rail from 5V input, twin-T 50 Hz notch network using 31.6k/15.8k and 100nF/200nF ratios, buffered conditioned ECG output, and 4-layer 70mm x 50mm layout constraints emphasizing analog cleanliness and ground continuity. - **System Architecture:** flowchart TD A[ECG Electrodes] --> B[Input Protection And Bias Network] B --> C[AD8232 ECG Front End] C --> D[50 Hz Notch Filter] D --> E[Output Buffer And ECG Output] F[5V Input] --> G[3.3V Analog Regulation] G --> C G --> D G --> E H[Ground And Reference Network] --> B H --> C H --> D H --> E - **Component Summary:** IC1 AD8232 ECG front end, U1 dual precision op amp for notch and output conditioning, U2 3.3V LDO, J1 3-pin ECG electrode connector, R/C network for 50 Hz notch filter, bias reference, decoupling, and output isolation. ## Key Components ### IC1 — [AD8232ACPZ-R7](https://www.flux.ai/adrian95/ad8232acpz-r7~egm.md) - Role Details: AD8232 analog front end for RA, LA, and RL electrodes in a driver drowsiness detection ECG chain - Part Type: Integrated Circuit - Package: LFCSP-20 - Role: ECG Front End - Datasheet URL: https://www.analog.com/media/en/technical-documentation/data-sheets/AD8232.pdf - Manufacturer Part Number: AD8232ACPZ-R7 - Manufacturer Name: Analog Devices Inc. - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - -IN [pin 3] - +IN [pin 2] - +VS [pin 17] - ~SDN [pin 13] - AC/~DC [pin 14] - FR [pin 15] - GND_1 [pin 16] - GND_2 [pin 21] - HPDRIVE [pin 1] - HPSENSE [pin 20] - IAOUT [pin 19] - LOD- [pin 11] - LOD+ [pin 12] - OPAMP- [pin 9] - OPAMP+ [pin 7] - OUT [pin 10] - REFIN [pin 18] - REFOUT [pin 8] - RLD [pin 5] - RLDFB [pin 4] - SW [pin 6] ### J1 — [TSW-103-07-G-S](https://www.flux.ai/adrian95/tsw-103-07-g-s~876.md) - Package: Through Hole 1x3 2.54mm - Role: Electrode Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Samtec Inc. - Role Details: Connector for RA, LA, and RL electrode lead wires - Datasheet URL: https://suddendocs.samtec.com/prints/tsw-xxx-xx-x-x-xx-xxx-footprint.pdf - Part Type: Connector - Manufacturer Part Number: TSW-103-07-G-S **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### U1 — [OPA2325](https://www.flux.ai/kicad-part-library/opa2325~cv.md) - Role: Active Filter - Manufacturer Name: Texas Instruments Inc. - Package: SOIC-8 - Manufacturer Part Number: OPA2325 - Package or Case Code: SOIC-8_3.9x4.9mm_P1.27mm - Datasheet URL: http://www.ti.com/lit/ds/symlink/opa2325.pdf - Role Details: Dual op amp used for a 50 Hz notch filter stage and buffered analog ECG output **Pins:** - - [pin 6] - - [pin 2] - + [pin 5] - + [pin 3] - ~ [pin 1] - ~ [pin 7] - V- [pin 4] - V+ [pin 8] ### U2 — [TPS78233DDC](https://www.flux.ai/kicad-part-library/tps78233ddc~48w.md) - Datasheet URL: http://www.ti.com/lit/gpn/tps782 - Role: Regulation - Manufacturer Name: Texas Instruments Inc. - Role Details: Low-noise 3.3V analog supply regulator from 5V input for the ECG front end and filter stages - Package: SOT-23-5 - Package or Case Code: SOT-23-5 - Manufacturer Part Number: TPS78233DDC **Pins:** - EN [pin 3] - GND [pin 4] - GND [pin 2] - IN [pin 1] - OUT [pin 5] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/bhumi233/careful-beige-lightcycle~x9](https://www.flux.ai/bhumi233/careful-beige-lightcycle~x9).* --- *Generated from [https://www.flux.ai/bhumi233/careful-beige-lightcycle~x9](https://www.flux.ai/bhumi233/careful-beige-lightcycle~x9)*