Week 6 — Electronics design

This week’s topic: Electronics design.

Individual assignment

Your personal work for this week — notes, photos, design files, and reflections.

Group assignment

Guangzhou (Chaihuo) — group documentation: using lab test equipment to observe an embedded microcontroller board.

Abstract

In the lab, the group used a digital multimeter and a digital storage oscilloscope to measure voltage and observe signals on a running embedded board (custom purple PCB with ESP32-WROOM, OLED, pushbuttons, and LEDs, USB-powered). Dial positions, wiring, and instrument readings were recorded to meet the Week 6 group assignment: use lab test equipment to observe the operation of an embedded microcontroller.

Location: Chaihuo Makerspace
Instruments: Digital multimeter DT-860B; digital storage oscilloscope OWON EDS102CV

1. Teamwork and lab setup

Before measurements, the group reviewed wiring and the measurement plan at the bench and checked steps against reference material on a tablet.

For me, this was a useful reminder that using test equipment is also a way of learning how to read a circuit calmly. I became more aware that measurement is not only about getting a number, but about connecting the reading back to the board behavior.

Team discussing the measurement plan at the bench with a tablet — Figure 1: Team discussion at the bench.

Breadboard / dev-board wiring was completed in the same space; the multimeter, jumper wires, and microcontroller board were visible on the table for shared work.

Team wiring and initial checks on the dev board — Figure 2: Wiring and on-site debugging.

At the Chaihuo Makerspace station, members soldered or probed the purple PCB using an iron or probes together with test gear; the multimeter, soldering station, and bench power equipment were arranged on the bench.

Testing the purple PCB at Chaihuo Makerspace — Figure 3: Workstation layout and instruments.

2. Device under test

Item	Description
Main board	Custom purple PCB with on-board ESP32-WROOM module
HMI	Small OLED display, several tactile pushbuttons, multiple LED indicators
Power	USB cable to the board edge (debug / power); a portable power module was also used on the bench (see oscilloscope setup photos)
Peripherals	Small red sensor daughterboard on a multi-wire harness (red / black / white, etc.); on-board and peripheral LEDs could be lit during tests to confirm operation

All measurements below were taken with the board powered and firmware running.

3. Multimeter

3.1 Model and range

Model: DT-860B
Use: DC voltage; verify probe placement and range before measuring.

Probe connections

Black lead → COM
Red lead → VΩmA (μA) jack (voltage, resistance, and low current; do not use this jack for high current)
The 10 A jack was not used in this session.

3.2 DC voltage (parallel)

Set the dial to the DC voltage (DCV) range, 20 V scale (suitable for ~5 V logic / supply). Place the probes in parallel across the supply or load.

DT-860B on 20 V DC range reading 5.00 — Figure 4: Multimeter on 20 V DC, display 5.00, consistent with a common 5 V supply level.

The reading was 5.00 V (interpreted per the selected voltage range), indicating a stable DC level at that node for comparison with oscilloscope high / low levels.

3.3 Probe short check (continuity / low-resistance)

Before measuring the circuit, touch the two probe tips together to confirm probes, leads, and meter inputs are OK; the display in the photo shows 001 (low-ohms / continuity-style indication per this meter and range).

Probe tip short check before measurements — Figure 5: Probe short check — display 001 as a routine pre-check.

Safety: For current, break the path and connect the meter in series with the correct jack and range. For voltage, use parallel placement; do not short high-current paths. When in doubt, start on a higher range.

4. Oscilloscope

4.1 Model

OWON EDS102CV (digital storage oscilloscope)

4.2 Probe wiring

Clip the probe ground (alligator clip) firmly to circuit GND; touch the probe tip to the pin or test point. Keep the ground lead short to reduce ringing.

Oscilloscope probe and ground on purple ESP32 PCB — Figure 6: Signal tip on the DUT, ground clip on GND.

Overall setup (oscilloscope, DUT, USB power, and probe):

OWON oscilloscope with USB-powered ESP32 board — Figure 7: Full setup — oscilloscope, purple board, USB power.

4.3 Waveform capture

Using the OWON EDS102CV, the group observed the signal on the selected pin, adjusted vertical and horizontal scales and trigger until the trace was stable, then captured the screen image below.

OWON EDS102CV screen capture — Figure 8: Oscilloscope display.

5. Bench supply and logic analyzer

The bench included a soldering station and DC power-related equipment. This report does not include separate bench supply panel readings. A logic analyzer was not used this week.