The brightness of the light is too low

[doseofnoor]

Describe the bug
The light has been described by 2 healthcare practitioners as "underpowered", enabling "difficulty clearly seeing TM due to low light/magnification."

To Reproduce
Steps to reproduce the behavior:

1. Place speculum on device
2. Insert into ear canal

Expected behavior
The tympanic membrane (TM) should be seen clearly with sufficient light.

Photos
N/A

Additional context
Add any other context about the problem here.

Failure Mode
The light source is not providing adequate brightness.

Effect
Cannot clearly see structures of the ear canal and tympanic membrane.

Cause
This may be related to the LED specs, Ohm resistor, or due to the LED being off-centre, leading to poor focused illumination through the speculum.

Mitigation / Control

1. Stop device distribution.
2. Change LED supplier to Digikey/Mouser (confirm LED specs) and adjust LED holder to centre the LED.
3. If low light effect persists, revisit ohm resistor value (i.e., <2.7 ((\Omega ))).

[tareko]

I can think of a few possibilities here:

1. The battery is low - mitigate by replacing battery and reassessing
2. The light source is pointed in the wrong direction, so it appears underpowered
3. Perhaps the colours are playing a role? What exactly does the head look like?

[apopanda]

I'm preparing a redesign of the otoscope head which would use the PCB with the resistor already integrated. The PCB being rigid and predictable lets us more accurately control the light, which could solve this. Standby while I finish the design, do the wiring and see if it works better.

[apopanda]

Is this enough brightness for the otoscope?

[tareko]

Is this enough brightness for the otoscope?

It's more or less impossible to tell from this photo. You would either need a comparator gold standard, or some way to measure actual lumens.

[apopanda]

Let's print it in Canada, it'll be simple to compare it with 2.0 next to it.

[apopanda]

Currently testing a couple of LEDs including incredibly powerful ones.
Nichia,NVSW219CT 5000K Min CRI 70

This one is incredibly overkill for what we need it for with max current at 750mA. It looks alright on the battery and 100 Ohm resistor, at 5mA. There is a very large overhead on the light intensity with it though.