Portable spot welder 2.1

ESP32 portable spot welder is a mini portable supercapacitor spot welder that can be controlled by one hand. It uses a single supercapacitor as a high current power source to provide sufficient instantaneous output power for spot welding. It also has constant power and constant current charging circuits to charge the supercapacitor to make up for the shortcomings of slow charging and short battery life of the supercapacitor.
 
Product Introduction:
TYPE-C interface is mainly used to burn programs for ESP32 C3 and charge the device (5V/2A).
It has TYPE-C-->supercapacitor input 7.5W (5V/1.5A) constant power charging and lithium battery-->supercapacitor maximum output 0.8A constant current charging circuit and can independently control the switch.
It supports the collection and display of parameters such as USB voltage, battery voltage, capacitor voltage, and weldment detection voltage and temperature.
0.96-inch ST7735 160*80 display screen displays various parameters
3 buttons for mode switching parameter setting function control and a toggle switch to control the power on and off machine.
It has a circuit to prevent super capacitor current backflow and reduce the capacitor standby leakage current.
It supports automatic spot welding and manual spot welding modes and can set multi-pulse welding time and number.
It has multiple function switches, parameter settings, over-temperature protection, under-voltage protection and other
 
function modes.
The initial page of power-on: K2 key selects the corresponding working mode and parameter setting. K1 key selects to enter or exit
automatic spot welding mode: automatically detects that the weldment is in place and automatically executes the preset spot welding parameter process for spot welding.
Manual spot welding mode: K2 key selects different working modes. Mode 0: Press K3 key to execute a spot welding parameter process. Mode 1: Press K3 key to start the spot welding MOS If not pressed, it will be closed.
Parameter setting mode: K2 key selects the corresponding setting parameter name. K3 key adjusts the parameter.
Charging setting mode: After entering with the power key, K3 key is used to set different capacitor charging modes. There are mainly automatic mode and manual mode. There are different charging path selections in the manual mode. The default spot welding process for spot welding
 
settings
adopts: spot welding delay + preheating pulse + multiple pulse interval times and multiple pulse combination modes of spot welding pulses. Any combination can also be used.
The weldment detection threshold is used to detect whether the weldment exists and the value of the capacitor voltage divider.
In actual use, when the capacitor voltage is lower than 2V, the solder joint will become unstable. It is recommended to use
60mS high-level spot welding above 2V. The capacitor voltage drops by about (0.05V~0.1V). 
Use appropriate parameters for spot welding materials of different thicknesses to achieve better spot welding effects.  
 
The charging setting
uses 2.7V/600F supercapacitor and 3.7V/400mAh lithium battery as the test sample by default.
The automatic charging mode automatically charges from 0.1V to 2.7V for the first time. It takes about 20 minutes (due to intermittent work of over-temperature protection).
The automatic charging mode automatically charges from 1V to 2.7V It takes about 8 minutes.
TYPE-C in manual charging mode-->Supercapacitor is charged from 1V to 2.7V. It takes about 8 minutes.
Lithium battery in manual charging mode-->Supercapacitor is charged from 1V to 2.7V. It takes about 20 minutes.
Manual charging mode. Non-charging mode is used for debugging and transportation.
When the USB and battery voltage are too low or the temperature is >50℃, the charging function will not be executed.
 
Program download.
This program is based on Arduino IDE development source program and dependent libraries. The compiled and exported burning files are included in the attachment.
Compilation environment: arduino1.8.19 / esp32_package_2.0.5
Before compiling, you need to install the relevant libraries and select the corresponding development board chip to set relevant parameters and precautions. In the source program header,
the chip will not be recognized when connecting to USB when downloading the program for the first time. You need to pull down the P9 pin first (press the K2 button) and then turn on the power switch to enter the forced download mode.
 
Hardware assembly (high cost solution)
This project uses ESP32 portable spot welder-2.1 by default. The PCB file includes the main control board and power board. Ordinary RF-4 material 2-layer board with a thickness of 1.6mm
The ESP32 portable spot welding machine is mainly composed of the main control PCBA + power board PCBA + super capacitor + lithium battery + M2 copper column screw + conductive copper block fixture + spot welding pin + transparent heat shrink insulation sleeve.
The super capacitor uses the 2.7V/600F 4-pin cylindrical packaged Lishen super Farad capacitor by default. See the picture for details.
The lithium battery uses a 3.7V/400mAh 602040 packaged soft-pack lithium battery. If there is enough space, the larger the lithium battery capacity, the better.
There are 3 diversion copper block fixtures, two for the left and right diversion pin fixtures, and one for the capacitor terminal diversion fixture. Designed by SOLIDWORKS 2021 and CNC processed by Jiali Chuang. The copper material
spot welding pin can only use a diameter of 1.8mm due to the limitation of the conductive copper block fixture. The pin length is about 25mm. You can use a 1.8mm copper rod to process and polish it yourself.
M2 copper column screw parameters: double-pass copper column (M2*3) x5 used as a nut + double-pass copper column (M2*10) x3 + Flat head screw (M2*3) x6 + Flat head screw (M2*9) x5
Transparent heat shrink insulation sleeve diameter 35mm Length arbitrary The above assembly device parameters are not counted in the cost to improve the spot welding effect and use experience
 
Hardware assembly (low-cost solution)
It is easy to assemble with 2.7V/500F flat-foot capacitors, but the spot welding effect is not very good. It is extremely difficult to weld the 2.7V/600F Lishen 4-pin capacitor without using a conductive copper block fixture. Use one of them.
The flat-foot capacitor power board is incompatible with the diversion copper block fixture. You need to cut the copper plate diversion and brass material by yourself: square one-in-one-out terminal block (16*5.3mm) as a low-cost alternative. For detailed information, see the picture.
Lishen 4-pin capacitor power board does not need a diversion copper block fixture to reduce costs, but you need to cut the copper plate diversion and brass material by yourself: square one-in-one-out terminal block (16*5.3mm) as a low-cost alternative.
If you use the terminal block as a welding pin fixture, then the welding pin can choose a 4mm diameter copper rod and process and polish it yourself. You can also buy a professional welding pin 
M 2. The parameters of the copper pillar screws are slightly different and need to be confirmed by yourself. The parameters of other devices are basically the same.
The low-cost solution is at the expense of spot welding effect, assembly difficulty and user experience. It is a personal choice.
 
Note:
This project is created for personal interest only. Open source is not a commercial product. It cannot ensure that it complies with any regulations and safety requirements. Any risks and consequences of using the products of this project are borne by the user. The
use of this product must comply with relevant laws and regulations and must not be used for illegal activities. Using this product means that you have read and agreed to this disclaimer.
Since the voltage of a single supercapacitor is only 2.7V, it cannot output a larger current when the overall internal resistance is constant, resulting in weak solder joints when spot welding nickel strips larger than 0.2mm. Spot welding of 0.1mm nickel strips is completely fine.
The parameters of the components are subject to the schematic diagram. The components that Jiali Chuang does not have are on Taobao. The relevant software and hardware information are all in the attachments. This project uses a large number of 0402 package components and has a complex structure. It is not recommended for novices to copy.
This project is a CC BY-SA 4.0 open source project. If you need to mass-produce for commercial use, you must find the original author for authorization for personal use and commercial sales of <100 sets. Free
 
communication platform.
This project is created only for personal hobby. Open source. Welcome all developers and enthusiasts to participate and jointly improve and promote the development of the project
. Lichuang open source: https://oshwhub.com/fj956391150/pian-xie-dian-han-ji
Gitee open source: https://gitee.com/arduino2021/esp32-portable-spot-welder-2.1.git
QQ communication group: 619331673
Entropy 2023-5-14
 
Physical display