Electronics manufacturing
The task for this week was to create our own electrical circuit that would at least blink. We had the option to build a pre-designed blinking circuit on a soldering board or a freeform version, a running light, or a matrix display. Another possibility was to design our own circuit. Since I have virtually no experience with circuit design and soldering, I decided to build a pre-designed circuit — the running light.
Circuit design
Since the circuit has already been designed, it wasn't much work around circuit design.
I have tried to create the same circuit scheme on KiCad.
To create your own scheme, you have to create project in the first place. After that, you can choose scheme aditor and start creating your
own scheme. It wasn't difficult to find the components used in the circuit from the available selection. Only for the timer and counter,
it was necessary to slightly adjust the positions of the inputs and outputs to match the schematic.
To create this project these SMD components are needed
- Resistor 1 kΩ, 10x
- Resistor 2.2 kΩ, 1x
- Resistor 10 kΩ, 1x
- Potentiometer 50 kΩ, 1x
- LED diodes (3 mm), 10x
- Capacitor 1µF, 2x
- Timer (NE555), 1x
- Counter (CD4017), 1x
- Connector, 1x
- Printed circuit board (PCB), 1x
Soldering
Next came the soldering. For the first time, I tried soldering SMD components.
We used a mix of tin for soldering. The key takeaways I learned from soldering are that it's essential to keep the
soldering iron at the correct operating temperature (in this case, 300°C), work quickly and precisely
(it's not ideal to apply too much or too little solder), and mount components correctly.
At one point, while soldering the counter, I accidentally tinned all the pad connections before soldering the component itself.
Because of this, I had to clean that section of the board with a desoldering wick. It's also worth mentioning that the longer
leg of an LED corresponds to the anode.
After trying out if it works (despite one LED diode, probably by wrongly solded resistor or LED diode), I have finished with some touches such as trimming LED dioeds' legs.
