DIY kits and starter bundles
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A fun little electronics project (HCKITS0027) that demonstrates how two popular off-the-shelf IC's can be used to perform a complex function. When built, pressing the button will cause the 10 LEDs arranged in a circular pattern to flash simulating a rotating wheel. This sequence will slow down and eventually stop at a random position. The kit contains all the components necessary including the PCB. There are some surface mount parts so a small amount of experience in soldering is recommended.
Contents in the kit are as follows:
1 x PCB
1 x KF301-2P
1 x 6 * 6 * 10 keys
1 x 1UF 50V Capacitor
1 x 47UF25V capacitance
10 x 5MM Red LEDs
1 x 1N4007
2 x 470K resistors
1 x 10K resistor
1 x 9014 triode
1 x 8-pin IC Block
1 x NE555
1 x 16-pin IC Block
1 x CD4017
How to build:
Soldering tip: When soldering components to a circuit board it is always best to start with the smallest components first. This helps keep the board flat and stops access to pads from being restricted by larger components. The first step is to start by soldering the small surface mount resistors, capacitors, and transistors. In your kit these will be packages in paper or plastic strips and their values are marked appropriately. These components are very small and it is wise when handling and positioning them to use a small pair of tweezers. The best technique to soldering them to the board is to first apply a small amount of solder to one of the pads on the PCB. The with the component held in your tweezers, carefully position the appropriate pad of the component against the soldered pad. Then with your soldering iron heat the solder so that it sticks to the component whilst gently pushing the components against the pad. Once the component is correctly positioned allow the solder to cool by removing the iron. The component should then be attached to the PCB and in the correct position for you to easily solder the remaining pad(s).
SM resistors and transistor:
Start by soldering the smallest components first.
Locate the two 470K resistors (usually in a white paper table and are labelled with the number 474), the 10K resistor labelled 103, and the transistor (small black 3 pin component). Solder these components to the PCB as show in the above image.
Surface Mount IC's:
Locate the 8 pin and 16 pin IC's. It is important that these are soldered in the correct orientation reference the above image and notice that the white bar on the IC's are to the top of the board.
Soldering tip: For the IC sockets, solder pins on the opposite ends of the socket first. That way if your socket is not flat the pads can easily be reheated one at a time to reposition the socket. Once flat, the rest of the pins can then be soldered.
Locate the surface mount diode and solder to S1. This components needs to be soldered in the correct orientation. Notice in the above picture the think black band on the diode is to the right.
Next locate the ten 3mm LED's. Like the diode these must be soldered in the correct orientation. You will notice that each LED has one leg slightly longer than the other. This is the positive leg or anode. Each LED leg needs to be inserted into the hole to the outside of the PCB.
Soldering tip: When soldering LED's (or similar through hole components), push the LED so that it sits flat against the PCB, then on the underside of the board splay the two legs outwards slightly. This will help hold the LED in place whilst it is being soldered. Do this for all 10 LED's then with the board sat against a flat desk, solder one leg of each LED. When you have soldered one leg of each LED check that all the LED's sit flat to the PCB then then solder the other legs.
Solder the push button to K1. The push needs to be orientated correctly. Notice that in the above image the legs are to the left and right of the components.
Power connector (optional)
The power connector is optional and can be soldered to the front or back of the PCB. If you wish to solder wires directly on to the PCB you can skip this step.
Finally solder the capacitors. There are two values, one marked 47uF which should be soldered to C1, and one marked 10uF which should be soldered to C2. Note that for both capacitors one pad on the PCB is marked with a '+' sign. You must solder the positive leg of the capacitor to this pad. You can identify the positive leg for both capacitors as the longer one of the two.
Your board is now complete. To power the board you will need a power supply between 3.5 and 6V. Note the '+' and '-' symbols by the power connector which indicates the correct orientation of the power supply.
The contents of this guide are copyright Hobby Components Ltd and may not be copied, reproduced, or reused elsewhere without permission.