An DIY (Do It Yourself) project for Embedded systems and Product Design

1. CONTROLLED
DIGITAL SOLDERING
STATION
Under the Guidance of
 DR. S R PANDIAN
Submitted by:
 A V V Y CHAITANYA (EDS16M003)
 B SUNIL KUMAR (CDS16M007)
 NAWIN K SHARMA (CDS16M009)
 VINAY KUMAR V (EDS16M004)

2. Our objective is to design and build Temperature Controlled Digital Soldering project
which has following desired features:
 simple in design
 Able to produce reasonably accurate and consistent temperature control.
 Low cost specially designed for electronic hobbyists.
PROJECT OBJECTIVE
TECHNOLOGY USED
 PD Control Tuning technique
 Thermocouple Sensing
 Embedded System
APPLICATION SCOPE
 Production lines for electronic products
 Repair industry for mobile phones

3. Simple Soldering Rod
 Simple Soldering Rod are Cheap in cost.
 They do not have any kind of thermal regulation.
 These directly plug into the wall socket (230v AC) and
heat up to a high temperature.
 Output is neither controlled nor stable, which leads to
poor-quality soldering and possible damage to the
components.
 When the soldering tip touches the joint, its
temperature drops as the heat is dissipated in the joint.
 If the part you are soldering can dissipate heat at a rate
more than what your soldering iron can deliver, the
temperature will keep dropping until it can’t melt
solder any more.
 This is normally the case when you are soldering
components on thick joints.
SOLDRON INDET021
Cost: Rs. 252.55
(Source: Amazon India)

4. Why do we need temperature
Controlled Soldering Station?
 Solder is a metallic alloy that, when melted it joins metallic surfaces.
 Different solder has different melting point.
 With a temperature-controlled iron, we can set the temperature beyond the
melting point of specific solder, but still within a safe limit for the
components.

5. Comparing with existing Products
 The Digital Soldering Station which are commonly available in the
market are usually sophisticated in design and therefore costly.
 These are more suitable in areas where a precise temperature control
may be required.
 Such hi-end types of control systems may be of no help or too expensive
to many electronic hobbyists.
 Also the cheap types are not reliable at all, because their accuracy is not
consistent.

6. Cost: ₹ 1,390
(Amazon India)
Yihua 936 Rework Soldering Station
• Features:
 Rapid heating
 Fast temperature compensation
 High-precision and stable temperature control

7. Soldering Rod
BLOCK DIAGRAM
MICRO CONTROLLER
(Arduino)
Thermo-coupler
Power I/P
Amplification using
IRF540
Potentiometer
(10K)
Analog I/P
24 power supply
Differential
amplification
using LM358
PWM
(Peak-to-Peak : 5V)
PWM
(Peak-to-Peak: 24V)

8. COMPONENTS NEEDED
 Arduino Board
 Soldering Iron Rod with Thermocouple
 LM358
 Resistors: 100k,1k
 Power supply
 Input:100-240V(AC),1.6A,Frequency :50-60Hz
 Output:24V(DC),3A(max)
 16x2 LCD Display
 IRF540
 Potentiometer 10k
 Heat Sink

9. Software used
 Arduino IDE
 Eagle
 Multisim
 MS Excel: For linear regression and calibration our datas
 www.draw.io :For drawing Flow Chart online

10. Flow chart for ON-OFF Control

11. Flow chart for PD Control

12. Soldering Iron Driver Circuit

13. Soldering Iron Driver Circuit PCB Layout

14. Thermocouple Voltage Amplification for
feedback

15. Thermocouple Voltage Amplification
circuit PCB Layout

16. Calibration of Thermocoupler voltage
with Temperature
0 36.7
1.00E-04 36.8
3.00E-04 36.9
1.20E-03 41
2.40E-03 48
3.50E-03 67
6.30E-03 90
9.40E-03 110
1.41E-02 145
1.41E-02 145
1.58E-02 155
1.83E-02 183.5
2.04E-02 200
Thermocouple Voltage Temperature

17. Thermocouple Voltage Amplification
Thermocouple
Voltage
Feedback
Voltage to
M/C
1.34E-02 1.21
1.70E-02 1.56
2.11E-02 1.96
2.45E-02 2.3
2.75E-02 2.59
2.88E-02 2.73
2.92E-02 2.75
3.03E-02 2.85
3.14E-02 2.97
3.24E-02 3.08

18. Calibration of Duty Cycle vs
Temperature of soldering rod
Duty Cycle(%) Temperature
19.60784 141.4564
29.41176 170.1318
39.21569 202.7899
49.01961 229.8723
58.82353 253.7685
64.70588 264.1235
68.62745 267.3097
72.54902 276.0716
78.43137 284.8336
82.35294 292.799 X-axis: Duty cycle(%)
Y-axis: Temperature (°C)
Drawn for 24 V peak to peak PWM

19. Reference
1. http://electronicsforu.com/buyers-guides/hardware-buyers-
guide/temperature-controlled-soldering-stations
2. V.A. Drebushchaka “Thermocouples, their characteristic
temperatures, and simple approximation of the emf vs. T” May
2014
3. http://www.datataker.comDatalogger_ManualMeasuring%20Tempe
rature%20with%20Thermocouples
4. John A. Shaw Process Control Solutions December 1, 2003
5. Jia-liang Song, Wen-long Cheng a, Zhi-ming, Shuai Yuan, Ming-hou
Liu a ‘’Study on PID temperature control performance of a novel
PTC material with room temperature Curie point’’