Instructions

Fitting the garments, running a recording, and getting the data out. Written for the person actually doing it — a research assistant on their first day, or a parent at home.

Before the first recording

1. Check the sensor batteries. The sensors run on replaceable CR2025 coin cells, changed by lifting the cover on the back. Tessalogger shows the charge level for each paired sensor; start a session above 80%. One cell lasts a full day (12–24 hours) of continuous streaming.
2. Install Tessalogger. You will get the download link for the installer upon a NAPPA purchase. NOTE! Only Android is currently available. iOS coming soon.
3. Pair the sensors. In Tessalogger, select the position the sensor will sit in — a limb for MAIJU, the waist for NAPPA — and hold the sensor close to the phone until it appears. Check that the sensor number shown in the app matches the number printed on the sensor, so you know which physical unit is which.
4. Choose the garment size. MAIJU is sized by body length — 68, 74, 80, 86 or 92 cm — and should fit snugly but comfortably, without stopping the child moving freely.

Fitting a garment

Sensor placement is what every analysis depends on. Four steps, and the three mistakes that spoil a recording.

1. Insert the sensors. Clip each sensor onto the snap-on mount inside its pocket — one per limb in MAIJU, one at the front of the waistband in NAPPA — in the orientation the user guide shows. The wrong orientation makes the data unusable.
2. Check the orientation and the pockets. Before starting, check in the app that each sensor is recording in the position it was paired to, and that the pockets face outwards, away from the midline, rather than having rotated to the front or back.
3. Fit the garment. Snug at every sensor position, loose everywhere else. Tighten the straps beside the pockets if a sensor can shift; on very slim limbs, a layer of clothing underneath helps. A sensor that rotates during the recording is read as movement.
4. Common mistakes. The three that spoil recordings: a sensor mounted the wrong way round, a suit loose enough for the sensors to turn, and the phone left in another room during a streaming recording.

Per garment

Running a recording

1. Start. Enter the participant identifier, check that every sensor shows as connected, and press record. Avoid pausing a recording: start a new one instead, because pausing can break the synchronisation between sensors.
2. During. With a streaming sensor (Movesense MD or HR2) the phone or tablet has to stay within about ten metres, in practice the same room; a tablet sleeve keeps it safe and to hand. With Movesense Flash, and with NAPPA on any sensor, the data is logged in the sensor and the phone can be put away. For MAIJU, set the room up for play — space to move, a mat, age-appropriate toys — and let the infant move on their own.
3. Stop. Press stop in the app and take the sensors out of the garment. For MAIJU, record at least an hour of free play; the analysis needs 30 minutes of detected playtime from at least three sensors, and the published sessions averaged about two hours. For NAPPA, record the night — the published studies used a 12-hour window, typically 7 pm to 7 am.
4. Download or upload. Raw data goes to your own device; uploading to Tessacloud is what produces the analytics.

Care and cleaning

Take the sensors off the garment before washing; they are water resistant but are not made for repeated laundry cycles. MAIJU is machine washed with a detergent intended for synthetic materials, and should be inspected for mechanical wear afterwards — pockets, seams and mounts. NAPPA is machine washed at 40 °C with standard detergents. Wash a garment after each recording. The garments last for over 50 washing cycles.

Troubleshooting

The short answers are on the FAQ. Anything not covered there goes through the feedback form — include the garment, the sensor model and roughly when the recording was made, and the answer comes back faster.