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2 layers77 × 28 mmGroveToPiMixed, the printed circuit board in 3D

A collection of small projects that can be grouped together

Size
77 × 28 mm
Copper layers
2
Thickness
1.6 mm
Parts
11
Nets
7
Pads
35
Tracks, vias
20, 0
Pours
2
Routed
Yes
KiCad
KiCad 7 (file 20221018)
Created
6 Dec 2023
Updated
4 May 2025

Overview

GroveToPiMixed is an open-source printed circuit board by codesqueak, from the codesqueak/SmallElectronicsProjects repository on GitHub. It is a 2-layer board of 77 × 28 mm with 11 parts on 7 nets, routed with 20 tracks and 0 vias.

README

gardenlightCompact/kicad/README.md

Solar Garden Light

Keywords: Garden light, solar light, LED, solar, circuit, QX5252F, oshpark, jlcpcb

The Problem

I have a number of post type solar garden lamps, with small circular solar cells at the top. These suffer from a number of problems:

  • The cell is too small to supply adequate power in the winter
  • The plastic coating on the cell degrades and becomes opaque
  • The electronics suffer from corrosion
  • The illumination level is low

The Solution

I decided to see if it was possible to replace the electronics package with something that would address the issues:

  • A larger, better packaged (hopefully!) solar cell was sourced
  • An efficient circuit was designed around the QX5252F LED driver
  • The electronics package was small enough to be dipped in a protective coating and housed in a closed container

Circuit

After looking at and testing various designs / component values I found the following configuration to be optimal.

ComponentValueComment
QX5252FTO-94Datasheet
Solar Cell2.5VSelect something that will supply adequate power in winter
Inductor100µHAlter this values to control the available current
Ni-MH Battery1.2VSelect something with adequate storage - 1900mAh Ni-MH Eneloop's seem to do the job but overspec'd
Diode1N5817Anything with a low voltage drop will do
LED20mA / 17500 mCdNice and bright with good coverage. Obtained some from Kitronik
Capacitor1μFElectrolytic. Serves to increase brightness noticeably but uses more power. Useful for stablizing power for self colour changing LED's

Note: The capacitor is optional and is only essential when you use colour changing LED's. If you just want to change the brightness, change the inductor.

Completed Item and Housing

The circuit can be implemented on a small piece of Vero-board. This is small enough to fit within the space taken by one AA cell. Closed dual AA cell battery holders are common and cheap to obtain from eBay, thus solving the protective environment issue.

The battery holder is then affixed onto the base of the solar cell using a silicone sealant.
Make sure to use a 'non-corrosive' type as some will attack various materials including copper.

Built Up Circuit - Front

Note: For testing, the solar cell, battery and LED are broken out on 2.54mm Dupont connector pins. For long environmental life you may want to solder the connecting wires before coating the whole unit with a conformal coating / liquid tape etc

Built Up Circuit - Back

Not the best image - the camera seems to have problems with the shiny copper surface.

PCB - JLC

I also had a number of PCB's made up by JLC. Very cheap, fast delivery and I like the selection of colours.

The gebers for both JLC and OSHPARK are included in the project if you want to make your own

Component Size Comparison

Parts

11
QtyValueFootprintReferences
4Grovecustom:GroveConnectorJ1, J5, J6, J7
3Conn_01x05_Male(RPiHeader)Connector_PinSocket_2.54mm:PinSocket_1x05_P2.54mm_VerticalJ2, J3, J4

The 7 most common of 11 parts.

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Questions

How big is the GroveToPiMixed PCB?

It measures 77 × 28 mm and has 2 copper layers, 1.6 mm thick.

What parts does the GroveToPiMixed use?

11 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the GroveToPiMixed KiCad files?

From the codesqueak/SmallElectronicsProjects repository on GitHub, at the commit this page was made from: the board is groveToPiMixed/kicad/groveToPiMixed.kicad_pcb and its schematic N1Clock/kicad/N1Clock.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the GroveToPiMixed design in my own project?

Its repository states no licence, so its author keeps all rights: ask codesqueak before reusing the design.