BLE Sensor Logger

Experiment guide

Study onboarding

1

Participant information

Collect demographics and guitar background.

2

Chord familiarization

Practice C, Em, D, and G before the task.

3

Calibration session

Collect normal fretting references.

4

Chord Form–Hold–Release

Run randomized trials with timed cues and repetitions.

5

Effort Manipulation

Ramp force from normal to hard, then back down to light across all chords.

6

Post-study questionnaire

Collect the participant's comfort, usability, and practicality ratings.

7

Strumming speed

Run 60, 90, 120, and 150 BPM blocks with cued and silent strumming.

8

Post-strumming questionnaire

Collect comfort, tempo-control, and practice-fit ratings after strumming.

Step 1 · Participant setup

Participant information

Please complete the participant profile before proceeding.

Participant profile

Record the session identity and basic participant attributes used across the study.

Name Required Use the participant alias or session identifier used for this study. Age Required Enter the participant age in whole years. Gender Required Choose the participant response exactly as reported. Handedness Required This will help interpret guitar posture and fretting strategy later.

Guitar background

Capture the playing context needed to interpret participant performance and effort changes.

Years of guitar experience Required Use 0 for beginners with no prior guitar experience. Weekly practice time (hours) Required Estimate typical practice time over a recent week. Please rate your proficiency level in playing open chords Required

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Ask the participant to self-rate open-chord proficiency on a 0 to 100 scale. Usual playing style Required Choose the participant’s default playing approach rather than an occasional technique.

Calibration session

Ask the participant to play each chord using normal fretting effort with the configured play and rest timings below. The chord order is randomized and the whole process is repeated 3 times.

Calibration target

NORMAL 8 s

Use your typical playing pressure and hold the chord for the full interval.

REST 2 s

Relax before the next randomized chord prompt begins automatically.

Sequence 12 prompts total

Four chords × one force level × three rounds. The session advances automatically.

Phase timings Seconds

Play Rest

Status Ready

Prompt 0 / 36

Target force —

Countdown 10.0 s

Normal0 / 12

Prompts covered0 / 12

The chord order will be shuffled for each of the 3 rounds using normal force only.

Live cue

Calibration chord

—

Waiting

10.0 s

Play 8 s, then rest 2 s

Chord chart will appear here.

Press start to begin the randomized calibration sequence.

Chord Form–Hold–Release experiment

Each trial follows the phase timings configured below. The chord order is randomized, with 10 repetitions each for C, Em, D, and G.

Protocol

REST 3 s

Relax your left hand.

FORM CHORD 2 s

Form the displayed chord when the beep sounds at phase start.

HOLD STILL 2 s

Keep the fretting hand still.

RELEASE 1 s

Release the chord.

Phase timings Seconds

Rest Form chord Hold still Release

Status Ready

Trial 0 / 40

Countdown 8.0 s

C0 / 10

Em0 / 10

D0 / 10

G0 / 10

The trial order will be shuffled when the experiment starts.

Live cue

Effort Manipulation session

Show one chord at a time and ask the participant to perform it with continuous force variation using the configured phase timings below. Complete all chords and repeat the whole session for 3 rounds.

Protocol

CHORD TRIAL 15 s

Perform the displayed chord and vary the fretting force slowly from light to hard.

REST 5 s

Pause between chords. Three shuffled rounds cover all four chords.

Phase timings Seconds

Form normal Ramp to hard Ramp to light Rest

Status Ready

Trial 0 / 12

Timer 15.0 s

C0 / 3

Em0 / 3

D0 / 3

G0 / 3

The chord order will be shuffled for each of the 3 rounds.

Live cue

Current chord

—

Waiting

Vary the fretting force slowly from light to hard, and then from light to hard, iteratively

20.0 s

Chord chart will appear here.

Strumming speed experiment

Run the speed blocks at 60, 90, 120, and 150 BPM. For each speed, cue the first 20 strums with beeps, then ask the participant to continue with 20 additional strums without sound cues before clicking Next.

Protocol

60 BPM 20 cued + 20 silent

Start with 20 beep-guided strums, then 20 more without sound cues.

90 BPM 20 cued + 20 silent

Repeat the same pattern at 90 BPM.

120 BPM 20 cued + 20 silent

Repeat the same pattern at 120 BPM.

150 BPM 20 cued + 20 silent

Finish with the fastest block at 150 BPM.

REST 10 s

Insert 10 seconds of rest between consecutive speed blocks.

Fretting chord Choose one

Select the chord the participant should fret during all strumming speed blocks.

Status Ready

Speed — BPM

Stage Ready

Timer 0.0 s

60 BPM0 / 40

90 BPM0 / 40

120 BPM0 / 40

150 BPM0 / 40

Tempo blocks will run in order: 60 BPM, 90 BPM, 120 BPM, and 150 BPM, with 10 seconds of rest between speeds.

Live cue

Current tempo

— BPM

Ready

Fretting chord —

Select C or Em to display the fretting chord.

Time to next beep 0.0 s

Next speed 60 BPM

Press start to begin the guided strumming session.

Post-study questionnaire

Ask the participant to drag each slider to rate the statement from 0 to 100. Complete all items before continuing to the strumming session.

Scale: 0 = strongly disagree 100 = strongly agree

Q1

The wearable sensors were comfortable to wear.

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Q2

I could clearly distinguish between light, normal, and hard pressing.

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Q3

I could perform the instructed pressure levels.

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Q4

The chord formation and transition tasks were similar to normal practice exercises.

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Q5

I was able to keep the chord still during the hold periods.

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Q6

I would be willing to use a wearable system like this during practice.

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Q7

The sensing setup seemed practical for repeated use.

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Post-strumming questionnaire

Ask the participant to drag each slider to rate the strumming session from 0 to 100. Complete all items before finishing the study guide.

Scale: 0 = strongly disagree 100 = strongly agree

Q8

The wearable sensors were comfortable during strumming.

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Q9

The strumming-intensity instructions were easy to follow.

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Q10

The strumming tasks were similar to normal practice exercises.

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Q11

I was able to keep the tempo steady during the tasks.

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Q12

I would be willing to use a system like this during guitar practice.

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Connection & Control

Step 1 · Connect Sensors

Not connected

Step 2 · Configure Measurement

Frequency (Hz)

Resistance

Sweep

Step 3 · Choose EIS Visualization

EIS Channels

Rate / Total

S1 EIS 0 Hz 0 pkts

S1 IMU 0 Hz 0 pkts

S2 EIS 0 Hz 0 pkts

S2 IMU 0 Hz 0 pkts

S3 Pressure 0 Hz 0 pkts

Latest Raw Packet

Ready.

Label & Recording

Step 4 · Mark data with labels

Ready to record

BLE Sensor Logger (Chrome)

Participant information

Participant profile

Guitar background

Chord familiarization

Calibration session

Calibration target

Live cue

Chord Form–Hold–Release experiment

Protocol

Live cue

Effort Manipulation session

Protocol

Live cue

Strumming speed experiment

Protocol

Live cue

Post-study questionnaire

Post-strumming questionnaire

Connection & Control

Rate / Total

Latest Raw Packet

Label & Recording

Sensor 1 EIS

Sensor 1 IMU

Sensor 2 EIS

EIS Compare · Sensor 1 vs Sensor 2 (Channel-by-Channel)

Magnitude

Phase

Sensor 3 Pressure

Sensor 2 IMU