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Project Notes

#419 lite2sound-bc

Building Lite2Sound Boldport Club Project #26.



Lite2Sound BC is the 26th Boldport project, and is a collaboration with Rare Waves LLC.

It uses a photodiode to detect audio-frequencies from light, which are amplified and piped to an audio jack (or optionally to direct line-out).

Best of all - it comes in an Altoids-sized can!

See the LEAP#420 CuttleTalk project for a full demo of the finished thing.

The Kit

Qty Ref Item
x3 C1,3,4 10µF electrolytic capacitors, Nichicon UWX1C100MCL2GB
x2 C9,11 220µF electrolytic capacitors,Multicomp MCVVT016M221EA6L
x2 C5,6 220pF C0G ceramic capacitors, Multicomp MC1206N221J500CT
x3 C2,7,10 100nF ceramic capacitors, Kemet C1206S104K5RACTU
x3 R7 10Ω resistors, Walsin WR12X10R0FTL
x3 R3,4 220Ω resistors, Walsin WR12X2200FTL
x3 R1,2,9 20KΩ resistors, Walsin WR12X2002FTL
x3 R5,6 2MΩ resistors, Walsin WR12W2004FTL
x1 D2 Schottky diode, Diodes 1N5819HW-7-F
x1   Photodiode, On Semi QSD2030F
x1 D1 Photodiode, On Semi QSD2030
x1 IC1 Low noise op-amp, Diodes TL072SG-13
x1 IC2 Power amplifier, TI LM386MX-1/NOPB
x1   3.5mm stereo socket, TruConnect PJ-301DM
x1 VR1 50kΩ pot, Suntan TSR3386F-EY5-503-TR
x2 SW1,SW2 Switch, C&K JS202011SCQN
x1   Battery contact positive, MPD BSPCF
x1   Battery contact negative, MPD BSPCM
x3   12.7mm self-adhesive feet, RVFM PD.2125
x1   Lovely PCB
x1   Metal enclosure with a hole
x1   Light blocking sticker for tin

Note: some resistors are provided in extra quantity than is required, and there are two versions of the photodiode.


As uaual, a beautiful PCB designed by Boldport:

kit_pcb_front kit_pcb_rear

Two Photodiodes?

The kits comes with a choice of two photodiodes: QSD2030 and QSD2030F. These are basically identical, but the QSD2030F is in black epoxy which provides a daylight filter. A daylight filter is intended to attenuate the effect of outdoor/sunlight and prevent it overwhelming other signals (from reports: YMMV)


  • Wide reception angle: 40°
  • Package material and color: clear epoxy
  • High sensitivity
  • Peak sensitivity λ = 880nm


  • Wide reception angle: 40°
  • Daylight Filter
  • Package material and color: Black Epoxy
  • High Sensitivity
  • Peak sensitivity λ = 880nm

I’m not planning extensive outdoor usage, so I built the kit with the standard QSD2030 without daylight filter.

Construction Tips from BC Slack!

…oh, the feet go on the tin. This sense makes (@kpreid)

.. saved me doing something stupid.

the board with this kit seemed to absorb a lot of heat when I hit it with hot air. took some time to heat up (@kbx81)

.. I used hot air for the SMD assembly, but didn’t have similar issues.


As provided by Boldport. Note: it doesn’t show SW1 (on/off), which is positioned after the reverse-polarity protection diode D2.


I used hot-air for SMD soldering, and an iron with my favourite 2% Ag solder for through-hole components and wires.

build_top build_bottom

With stickers attached to the case:

build_case_top build_case_bottom

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.