Project files

sidebar_position: 4

import useBaseUrl from '@docusaurus/useBaseUrl';

export const ImgWithBaseUrl = ({src, alt, width}) => (

);

Soldering Guide

Soldering Auxiliary Tools

Key Points for the Module Board

Non-Modular Boards

• Microphone: The GND pin (pin 3) must be fully soldered; otherwise, heat dissipation will be unstable and the microphone may burn out. Avoid prolonged exposure to the heat gun. Tin the pad first, then melt the solder quickly and place the microphone on it. Refer to the manual for soldering temperature:
• Amplifier: Pay attention to the orientation; the "+" sign corresponds to the white dot in the upper right corner.
• ESP32: It is best to solder the bottom pads. Apply a bit of solder paste and place it on a heating plate or use a heat gun.
• LED: The left side is the negative pole. The green vertical line on the LED should face left, or check the triangle on the bottom—the pointed end should face left. This LED serves as the charging indicator and will glow faintly without a battery inserted.

Required Tools

Soldering the Otto robot requires the following basic tools:

• Temperature-controlled soldering iron: A soldering iron with adjustable temperature settings, recommended at 320–350°C
• Solder wire: 0.8 mm diameter leaded solder recommended (60/40 or 63/37)
• Flux: Helps the soldering process go smoothly
• Soldering iron stand: Used to hold the soldering iron
• Solder wick/solder sucker: Used to correct soldering errors
• Tweezers: Used to place small components
• Magnifying glass/microscope: Used to inspect solder joints
• Alcohol: Used to clean the PCB
• Heat gun: Used to remove components (optional)

Post-soldering inspection

After completing all soldering, perform the following checks:

1. Visual inspection: Inspect all solder joints to ensure there are no cold solder joints or short circuits.
2. Continuity test: Use a multimeter to test the continuity of critical points.
3. Clean the PCB: Clean residual flux from the PCB with isopropyl alcohol.
4. Short-circuit check: Check for short circuits between power and ground.
5. Functional test: Plug in the USB cable and check if the device is recognized normally.
6. Voltage test: Check if the voltage at critical test points is normal.

Advanced Soldering Tips

1. Control soldering time: Do not heat each solder joint for more than 3–5 seconds.
2. Keep the iron tip clean: Clean the iron tip regularly to ensure good heat transfer.
3. Correct soldering angle: Maintain a 45-degree angle when touching the solder pad and component lead.
4. Sufficient heat transfer: Make sure to heat both the pad and the component lead simultaneously.
5. Patience is key: Do not rush, especially when working with small components.

Frequently Asked Questions

Q: Why won’t my solder stick to the pad?

A: The pad may be dirty or oxidized; try using flux and ensure the soldering iron is at the correct temperature.

Q: How do I judge the quality of a solder joint?

A: A good solder joint should be smooth and shiny, forming a conical or volcano shape and fully fused with the pad and component leads.

Q: What if the ESP32 pins are too close together to solder?

A: Use a fine-point soldering iron with flux, or consider using a hot-air gun with solder paste.

Q: How do I check for short circuits after soldering?

A: Use the continuity test function on a multimeter to check for unintended connections between adjacent pins.

Q: What are the most common mistakes beginners make?

A: Poor control of solder volume (too much or too little), insufficient or excessive heating time, and not using flux.

Next Steps After Soldering

After completing the soldering, you can proceed with the following:

1. Download the Program – Flash the firmware for your Otto robot
2. Assembly Guide – Assemble the soldered PCB into the 3D-printed shell