I've recently taken an interest in electronics and decided I wanted to try my hand at soldering surface-mount devices (SMD) to circuit boards. I've seen many YouTube videos (see links below) on how to do this, but my practical experience has been minuscule, involving only a few single-chip breakout boards.
In order to gain a bit more experience with SMD soldering, I searched Amazon for any SMD practice boards. There aren't many, but there are a few. I selected the Gikfun EK1885 kit (Amazon link), because in addition to being a board to practice on, half of the board actually does something - it uses a timer and a counter chip to make a group of LEDs flash in a simple pattern.
The only problem with the board is that the instructions are all in Chinese (see image, above). Fortunately, circuit schematics are language-independent and I was able to figure out enough of the parts list to assemble the board without translation, but it was still annoying not knowing what the text actually says.
Fortunately, I have a friend who is a native speaker of Chinese. He was able to translate the instructions to English. And so, as a service to the rest of the world (including those on Amazon who complained about being unable to read the instructions), I have cleaned up the English a bit (since the raw translation doesn't read very well) and I present the result here:
NE555 + CD4017 Primary SMT Soldering Practice Kit1. Product Description
The Super SMT Soldering Practice Kit is designed for practicing the skill of electronic assembly and testing. Most electronic products are made with surface-mount components, mounted and connected by soldering. To manufacture such a product, soldering skill is needed. This practice kit consists of NE555 and CD4017 chips, which produce a flashing light "water flow" from red LEDs and other commonly-used electronic components. The popular NE555 chip is used as the oscillator, which controls the red LEDs via a CD4017 digital counter. The product is good for learning electronic circuit analysis.
2. Brief Description of the Design Principle
The NE555+CD4017 flashing light "water flow" red LED circuit consists of two main components: an oscillator made from an NE555 single-shot trigger circuit and a 14-layer binary serial counter. The frequency is determined by C27, R48 and R49 and can be calculated by F = 1.44/(R48 + 2 * R49) * C27. Pulses from the oscillator are the output of 3rd pin of the NE555 and drive the CD4017. The 14th pin of CD4017, the clock pin, is connected to the 3rd pin of the NE555 to provide its clock signal. Pins 8, 13 and 15 are grounded. The y0-y9 pins are connected to 10 LEDs, D2 to D11, via current-limiting resistors, arranged in a circle. When power is applied, the y0-y9 pins are powered in sequence, lighting the 10 LEDs.
3. Itemized parts list
Name Package Specification Quantity Part number SMT Resistor 805 10 kΩ 5 R48, R61-64 805 2 MΩ 1 R49 805 470 Ω 15 R50-R60, R65-R68 SMT Capacitor 805 0.1 μf 2 C27, C28 SMT Diode LL34 IN4148 4 D12-D15 Red LED 805 LED 11 D1-D11 Blue LED 805 LED 4 D16-D19 SMT Transistor SOT-23 S8050 4 Q1-Q4 SMT IC SO-8 NE555 1 U1 SO-16 CD4017 1 U2 Itemized list of components for soldering practice SMT Resistor 402 random 20 * 603 random 10 * 1206 random 8 * SMT Capacitor 603 random 10 * SMT Diode LL34 random 10 * SMT IC SO-14 random 2 * QFP44 random 2 * SMT Transistor SOT-23 random 6 *
Oh, and in case you're curious, here's a quick video showing the circuit actually operating:
Useful links:
- ElectroSome: CD4017 Decade Counter with 10 Decoded Outputs
- YouTube: EEVblog #180 - Soldering Tutorial Part 1 - Tools
- YouTube: EEVblog #183 - Soldering Tutorial Part 2 (through-hole soldering)
- YouTube: EEVblog #186 - Soldering Tutorial Part 3 - Surface mount
- Wikipedia: 555 timer IC
1 comment:
Thank you very much, this was quite helpful and I appreciate your work in creating and posting these instructions.
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