Free-Formed Solar Chirping Bird Pendant Using 0603 SMD Components (BEAM Electronics)
Introduction: Free-Formed Solar Chirping Bird Pendant Using 0603 SMD Components (BEAM Electronics)
I had one weekend between finishing quite a stressful university term and starting to study for my exams so I thought, "You know what would be really relaxing, finally trying to make a free-frormed circuit using 0603 components.". No way that could be stressful right? 😂😂
The final circuit chirps on and off for about 20-40 seconds (watch the video to hear it chirping) and then stays off for another 1-2 minutes before chirping again.
I originally just wanted to make this as small as possibly but in doing so I realised it could actually be made as a pendant and I am very glad I turned it into a pendant in the end as I think the frame adds so much to the circuits aesthetic and protects the circuit from getting damaged. I don't intent to wear this often (in fact I hardly expect to let it see the sun at all because, as I know from previous chirping circuits, the noise gets old quick) but I reckon this would be the absolute perfect thing to wear to a maker faire or similar event!
In the final photos in the introduction you can see my first attempt to miniaturize this circuit by designing a PCB back in 2019 (this was one of my first PCB projects and it doesn't even work, the solar panel is too small!). As well there is a comparison in size between the breadboarded version, PCB, and free-formed SMD version
Edit: wobbler has kindly amplified the chirping audio as it was a little quiet in the original video. If you are struggling to hear the chirping in the video try the audio file attached below. It is still very true to how the circuit sounds in real life just louder and clearer =).
Supplies
EDIT: I don't know what happened here but my supplies section seems to have disappeared at some point so I will summarise the important components again.
Resistors: All 0603.
Capacitors: 0603 for the 1nFs and the rest had to be 0805 as they are much easier to source. I also used a couple of axial 10nF caps.
Diodes: 1N4148WS.
Photodiode: I used a VEM6010X01CT-ND though any choice will probably do and you may be able to find smaller with a more suitable pinout.
Solar panel: KXOB25-02X8F-TB which is a very small and efficient 5.5v panel. Quickly becoming a favourite for me!
Super capacitor: 100mF, 5.5v square super capacitor from KEMET.
Piezo element: 9x9mm externally driven piezo speaker.
Inverter IC: 74HC14 SOIC (hex Schmitt inverters)
Brass: 0.02" (0.51mm) for most of the circuit. 1003
3/64" (1.19mm) for the frame 1/32" (0.81mm) for the loops.
Tools: Most important for this project is a clean soldering iron tip, flux, and good solder. I used multicore 60/40 solder at 0.7mm which was fine but at times I did want thinner solder. Also important for soldering are fine tweezers, Blu Tack, and perhaps some form of magnification (I was lucky I did not need magnification for this project as I am not used to working through a microscope or anything so it gives me headaches). You will also need various jewellers pliers (I bought a set from my local electronics hobby store that work great) and sids cutter for forming the brass.
Step 1: Schematic
This is yet another circuit that was originally designed by <PERSON> way back in 199 (found on the solarbotics.net site). I have modified it a little, mostly to change the frequency of chirps, and a few other modifications to make it sound less robotic.
The circuit is essentially just 4 oscillators. From left to right, the first and second oscillators turn on and off slowly to turn the other oscillators on and off. In Wilf's original circuit this creates some kind of randomness in the number of chirps but the circuit is constantly chirping. With the components I chose, the circuit turns off for a very long time (1-2 minutes) and is on for a shorter time (20-40 seconds) based on the second oscillator values (10uF, 10M, 5M). The first oscillator values (1uF, 10M, 3. 552