How do i? - Make a Very Compact Solar Panel Charged System

To anybody who knows more than me,

I am designing a Snowboard Brake for my 2019 Design and Technology HSC project. It is an independent device that sits underneath your front foot when snowboarding. The actual braking system is not what I am seeking help with, but is a secondary feature of implementing immerging technology. This technology can be Solar panels, or Bluetooth or GPS, etc.

The space that I can fit the electronics into is about 100mm * 80mm * 10mm, the length, and breadth is flexible but the height requirements is a hard 10mm. Any solar panels are not included in this space, they can be external.

I have come up with a Solar Panel Charged system with a rechargeable battery. This then powers a Bluetooth module which I can then control LED’s, and have access to a reed switch which when activated will activate a buzzer and notify a phone via Bluetooth.

Through research, I have found that using a Solar Lipo Charger ( with an input of a 5v 500 mAh Solar Panel charging a LiPo 3.7V 1000mAh Battery ( The output of the Solar Lipo Charger then powers a Bluno Beetle ( which can control a reed switch, a buzzer and LED’s via Bluetooth. An app will also need to be developed to control this.

Instead of LED’s and a Buzzer, a GPS module could be implemented but I have no idea about power requirements, etc for the GPS module.

With the battery, I have no idea what to do when the battery is fully charged or how to stop charging when it does.

If anyone can help, please do, I can work circuits but have no idea when it comes to components and their compatibility. Any tips on what components to use or how to wire the circuit would be of amazing help to me.

Jordan Whittaker

Hi Jordan,

I’m not clear on what you are trying to build.

A solar panel with rechargeable battery, that powers LED lights that is controlled by Bluetooth?
What is the function of the reed switch and the buzzer?
What purpose would a GPS serve?
Is this on the snowboard or a completely separate device?

Sorry, I overcomplicated it.

This is a separate device that sits under your foot when snowboarding.

There is a very limited space where I can place my electronics as it is very thin.
My idea was having a solar panel with a rechargeable battery, that powers LED lights that are controlled by Bluetooth. Having an accelerometer as well, so when the device is moved it will notify you via Bluetooth. A GPS system could also be used so it can also see whether the device is being moved and also can track your position and map where you have snowboarded.

This is my device and the designated area has been shown.

You undoubtedly have a clear picture of the final product and the way it should work, and I just wanted to share an important concept around prototyping. Often, prototypes are a lot larger than they “need” to be, using modules and not-optimized electronics to prove a use-case. 100x80x10mm is enough to do a lot, and I recommend you start with something such as a WiPy which has WiFI, BLE and a powerful processor and operates with MicroPython. Then you are free to explore any accelerometer module, LEDs, whatever. Once it’s all working from a code perspective, those bits and pieces can be pulled into a dedicated printed circuit board and made to be incredibly small by comparison of the prototype.

Taking that approach means you don’t over-invest in any one hardware direction. You get the elbow room to pivot and explore ideas, changing out hardware quickly, etc.

And Fyi, the daily energy footprint for all of those systems will very-likely exceed the daily energy captured by the solar panel. GPS is very taxing (40+mA). You’ll need to break that down in your system mud-map to ensure the energy-in energy-out formula holds.

Hey Graham, your advice is a lot of help, especially knowing that once the code aspect of my device is figured out, printing a custom board can be very small and cheap. The WiPy board seems very useful and relevant aswell.

One problem I forgot to mention, is if i am charging a battery with a solar panel, what happens when it is fully charged. Grounding it seems hard, i could connect it to some metal aspects of my device but i have no idea. Anyone have any idea what to do?