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114 changes: 114 additions & 0 deletions docs/LGEO_SMT_Soldering_Challenge/lgeo_smt_soldering_challenge.md
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# Leeman Geophysical SMT Soldering Challenge

<div style="text-align:center;">
<img src="../product.png" alt="Instrument cover photo." style="height:400px">
</div>

### Required Equipment
<ul>
<li>Soldering Iron</li>
<li>Solder</li>
<li>Tweezers</li>
<li>Safety glasses</li>
<li>Optional: Flux</li>
<li>Optional: Microscope (recommended)</li>
</ul>

### Kit Components
Note: Only one of each electrical component is required for the PCB build, but a spare for each is included. These parts are small and easy to lose!
<ol>
<li>x1 - Challenge Printed Circuit Board (PCB)</li>
<li>x2 - (R1) 1206 150ohm Resistor</li>
<li>x2 - (R2) 0805 150ohm Resistor</li>
<li>x2 - (R3) 0603 150ohm Resistor</li>
<li>x2 - (R4) 0402 150ohm Resistor</li>
<li>x2 - (D1) 1206 Green LED</li>
<li>x2 - (D2) 0805 Green LED</li>
<li>x2 - (D3) 0603 Green LED</li>
<li>x2 - (D4) 0402 Green LED</li>
</ol>

<div>
<img src="../ToC.png" alt="Table of Contents" style="height:400px" />
</div>

### Safety Considerations
<ul>
<li>Assembling this kit requires the use of hot tools and small components.</li>
<li>Wear safety glasses when assembling this kit.</li>
<li>This kit and the solder you are using may contain lead. Wash hands thoroughly after assembling and do not eat or drink while working or handling kit materials.</li>
<li>Always ensure your work area is clean and safe. Never leave a hot or sharp instrument unattended.</li>
</ul>

## Before you Begin
Using the kit contents checklist, lay out and inventory your kit. Make sure you have all parts before beginning. This kit contains only surface mount technology (SMT) components that will be soldered by hand.

## What is SMT?
SMT (Surface Mount Technology) is a type of component mounting and soldering method used in modern high-volume circuit production. It differs from TH (through-hole) soldering, which you may be more accustomed to, in that the component does not pass through the PCB via wire leads. Instead, it sits on top of copper pads and is held in place and electrically connected through solder.<br>

In production, finely ground solder mixed with flux is formed into a paste and screen-printed onto the board so that every exposed pad is covered. Components are then placed onto these pads either by hand or via an automated pick-and-place machine. Once all components are loosely positioned, the board is passed through a multi-stage reflow oven where the flux is activated and cleans the electrical connections, followed by melting of the solder paste, which bonds the components to the board both mechanically and electrically once cooled.<br>

Although this process is typically automated, SMT soldering can also be done by hand using standard solder and a soldering iron. This is often required for repairing electronics and replacing components.

## Basic Guide for Hand-Soldering SMT Components
<ol>
<li>Before starting any SMT hand soldering work, thoroughly clean the tip of your iron to remove any debris or old solder.<br>
<b>Tip:</b><br>
Good lighting and magnification can make SMT soldering significantly easier, especially when working with 0603 and smaller components.
</li>


<li>With a clean iron tip, melt a small amount of solder onto one pad. Do this quickly to avoid burning off all of the flux from inside the solder. If the tinned pad appears spiky or dull, apply some more flux and reflow the pad again until shiny and round.
<div>
<img src="../example1.jpg" style="height:200px" />
<img src="../example1a.jpg" style="height:200px" />
</div>
</li>

<li>With tweezers, hold the LED or resistor in position just behind the tinned pad. Carefully melt and slide the component into position so that the tinned pad bonds to the edge of the component and the pad, tacking it into place. Adding more flux before doing so will make this process more forgiving.
<div>
<img src="../example2.jpg" style="height:200px" />
<img src="../example2a.jpg" style="height:200px" />
<img src="../example2c.jpg" style="height:200px" />
</div>
</li>

<li>Now that the component is tacked in place on one side, gently apply a moderate amount of solder and heat to the other side of the component. Once the joint is properly soldered, you can touch up the first side with a small amount of fresh solder if needed.<br>
<b>Tip:</b><br>
If you accidentally create a solder bridge, apply additional flux and use a clean iron tip to pull the excess solder away from the connection.
<div>
<img src="../example3.jpg" style="height:200px" />
<img src="../example3a.jpg" style="height:200px" />
</div>
</li>
</ol>

## Challenge Board Assembly Guide
Using the techniques shown in the basic guide, we challenge you to see how small you can go! This challenge PCB is designed to start off easy and progressively become more difficult. SMT resistors and LEDs come in standard sizes ranging from the hobby-friendly 2512 package (0.25") down to the incredibly small 0201 package (0.02"), commonly found in modern smartphones and other compact electronics.<br>

Although SMT packages are available in both larger and smaller sizes, for this challenge you will start with 1206 components and work your way down to 0402. After completing each resistor/LED pair, we encourage you to apply 3.3V and Ground to the PCB to check your work. If everything has been soldered correctly, a bright green LED will illuminate, indicating that size has been completed successfully. <b>ALWAYS</b> remove power before continuing to the next size.<br>

<b>Important Details:</b><br>

Each resistor in the kit is labeled with an R followed by its package size, and each LED is labeled with a D followed by its package size. Start with the largest components and work your way down. While resistors are non-polar and can be installed in either orientation, LEDs are polarized. Each LED differs in the orientation annotation. Follow the bellow to ensure you are soldering them correctly. <br>
<ul>
<li>1206: Green Edge, align with silkscreen line</li>
<li>0805: Green Edge, align with silkscreen line</li>
<li>0603: Small Silver dot, align with silkscreen line</li>
<li>0402: Dark line, align opposite to silkscreen line</li>
</ul>

Start with 1206 and work your way down. Good luck!

## Revision History
<table>
<tr bgcolor="gray">
<td><b>Date</b></td>
<td><b>Changes</b></td>
</tr>

<tr>
<td>June 2026</td>
<td>Initial Release</td>
</tr>
</table>
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167 changes: 167 additions & 0 deletions docs/Open_Logger_Lab_Kit/open_logger_lab_kit.md
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# Open Logger Lab Kit Assembly Guide

<div style="text-align:center;">
<img src="../product.png" alt="Instrument cover photo." style="height:400px">
</div>

### Required Equipment
<ul>
<li>Soldering Iron</li>
<li>Solder</li>
<li>Flush cutters</li>
<li>Safety glasses</li>
</ul>

### Kit Components
<ol>
<li>x1 - Circuit Board Assembly (PCB) w/ SMT Components</li>
<li>x1 - CR2032 Battery Holder</li>
<li>x1 - ESP32 Dev Kit PCBA</li>
<li>x2 - 19 Position Female Header (2.45mm)</li>
<li>x1 - Green LED</li>
<li>x1 - 5V DC-DC Converter</li>
<li>x1 - MCP7940 Real Time Clock (RTC)</li>
<li>x2 - Automotive Fuse Clip</li>
<li>x1 - 1A Automotive Fuse</li>
<li>x1 - Reverse Polarity (RP) Protection Diode</li>
<li>x6 - 2 Position Terminal Block</li>
<li>x1 - 10k Thermistor (B = 3950k)</li>
</ol>

<div>
<img src="../ToC.png" alt="Table of Contents" style="height:400px" />
</div>

### Safety Considerations
<ul>
<li>Assembling this kit requires the use of hot and sharp tools.</li>
<li>Wear safety glasses when assembling this kit. Clipped leads can shoot away quickly and cause eye injury.</li>
<li>This kit and the solder you are using may contain lead. Wash hands thoroughly after assembling and do not eat or drink while working or handling kit materials.</li>
<li>Always ensure your work area is clean and safe. Never leave a hot or sharp instrument unattended.</li>
</ul>

## Before you Begin
Using the kit contents checklist, lay out and inventory your kit. Make sure you have all parts before beginning. This kit contains only through-hole components that will be soldered by hand.

For a quick refresher on the basics of through-hole soldering, see our [Introduction to Through-Hole Soldering](https://leemangeophysical.com/introduction-to-through-hole-soldering/) guide.

## Assembly
<ol>
<li>
<h4>CR2032 Battery Holder</h4>
To begin this project, locate the CR2032 Battery Clip. Place the component in the correct position so that the square-notched end aligns with the matching shape on the PCB silkscreen. While holding the component in place, flip the board over and solder each pin in place.
<img src="../cr2032_ibom.png">
<img src="../cr2032_a.jpg" width="49%">
<img src="../cr2032_b.jpg" width="49%">
</li>

<li>
<h4>Green Power LED</h4>
Locate the green LED. This component is polarized like the CR2032 battery, so orientation is important. Notice that one wire lead is shorter than the other. This shorter lead is called the cathode and is also identified by a small flat edge on the side of the LED.
Place the LED in the Power LED position so that the short lead and flat edge align with the flat edge and square pad of the silkscreen circle. Once positioned, flip the board over and solder the two connections. Onces the solder connections are solid and clean, use flush cutters to snip the excess lead just above the solder joint.<br>
NOTE: It can be helpful to bend the leads in opposite directions to hold the LED in place before soldering.
<img src="../green_led_ibom.png">
<img src="../led_a.jpg" width="49%">
<img src="../led_b.jpg" width="49%">
<img src="../led_c.jpg" width="49%">
<img src="../led_d.jpg" width="49%">
</li>

<li>
<h4>DC-DC Converter</h4>
The next component is a DC-DC converter that steps the incoming 12V supply down to a regulated 5V to power most of the components on the logger. Place the converter into the PCB and solder its three connections.<br>
Ensure that the outline of the component aligns with the silkscreen rectangle to avoid installing it backwards.
<img src="../dcdc_converter_ibom.png">
<img src="../dcdc_a.jpg" width="49%">
<img src="../dcdc_b.jpg" width="49%">
</li>

<li>
<h4>Reverse Polarity (RP) Diode</h4>
In the even that the circuit is connected incorrect to a high current power source, this diode prevents current flow that could damage the PCB Assembly. Diodes are polarized components, so orientation is important. The cathode is identified by a thin ring around one end of the diode's body.
Bend the leads into a U-shape and place the diode into the RP Diode position. Ensure that the ring on the diode aligns with the matching line marked on the PCB footprint.
<img src="../rp_diode_ibom.png">
<img src="../diode_a.jpg" width="49%">
<img src="../diode_b.jpg" width="49%">
</li>

<li>
<h4>Thermistor</h4>
The thermistor is a temperature-sensitive resistor. Like a standard resistor, it is non-polar and can be installed in either orientation.<br>
Place it into the PCB as you did with the diode, then solder it into place.
<img src="../thermistor_ibom.png">
<img src="../therm_a.jpg" width="49%">
<img src="../therm_b.jpg" width="49%">
</li>

<li>
<h4>Automotive Fuse Holder</h4>
Next, solder the two automotive fuse clips onto the PCB. Each clip forms one half of the full fuse holder assembly.<br>
To ensure proper alignment and help protect your hands from heat conducted through the metal clips, first slide each clip onto the legs of a 1A automotive fuse. This is a non-polar component, so orientation does not matter.<br>
Insert the assembled clips into the four PCB holes as a unit, hold them in place, then flip the board over and solder them as straight as possible.
<img src="../autofuse_clip_ibom.png">
<img src="../fuse_a.jpg" width="49%">
<img src="../fuse_b.jpg" width="49%">
<img src="../fuse_c.jpg" width="49%">
<img src="../fuse_d.jpg" width="49%">
</li>

<li>
<h4>Terminal Blocks</h4>
Let’s add the 2-position terminal blocks. Ensure the wire entry openings on each block face outward from the PCB edge.<br>
Hold each terminal block in place and solder them one at a time.
<img src="../terminals_ibom.png">
<img src="../term_a.jpg" width="49%">
<img src="../term_b.jpg" width="49%">
</li>

<li>
<h4>Real-Time Clock (RTC)</h4>
Let’s step up the challenge! Next, you'll solder an 8-pin RTC (Real-Time Clock) integrated circuit. This package style is very common, and its pins are numbered 1 through 8. To ensure proper installation, both the chip and the PCB include markings that indicate the location of Pin 1.<br>
On the top of the chip, look for a small dot near one of the corners. This dot marks Pin 1. Align this mark with the small semicircle shown on the PCB silkscreen, then place the chip into position.<br>
While holding the chip in place, carefully flip the PCB over and solder all eight pins.
<img src="../rtc_ibom.png">
<img src="../rtc_a.jpg" width="49%">
<img src="../rtc_b.jpg" width="49%">
</li>

<li>
<h4>ESP32 Dev Kit (Microcontroller)</h4>
For our final component, you will add the 38-pin microcontroller. For this, we will use female headers to allow the ESP32 Dev Kit to be easily removed and replaced.<br>
As with the fuse assembly, slide each 19-pin header onto the corresponding row of pins on the Dev Kit. Once both headers are attached, place the entire assembly into the PCB, ensuring the USB port aligns with the edge of the board.<br>
Hold it in place, flip the board over, and solder all 38 pins.
<img src="../esp32_ibom.png">
<img src="../esp_a.jpg" width="32%">
<img src="../esp_b.jpg" width="32%">
<img src="../esp_c.jpg" width="32%">
</li>
</ol>

The Open Field Logger Kit is now complete. Take a moment to inspect each solder joint.<br>
For each joint, the following should be true:
<ul>
<li>The pad is fully covered with no exposed copper</li>
<li>Smooth, cone-like shape</li>
<li>Even shine (not dull in color)</li>
<li>No solder connecting adjacent joints (solder bridges)</li>
</ul>
<img src="../solder_joint.png">

## Documentation
<ul>
<li><a href="../schematic.pdf">Schematic</a></li>
<li><a href="../layout.pdf">Layout</a></li>
</ul>

## Revision History
<table>
<tr bgcolor="gray">
<td><b>Date</b></td>
<td><b>Changes</b></td>
</tr>

<tr>
<td>June 2026</td>
<td>Initial Release</td>
</tr>
</table>
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