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HowTo: A low cost lighting sequencer (Pt 1)
( Roger Otis)
Step 4 : The Circuit Boards
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| | I use breadboards available from Radio Shack (276-174, about $15) for most of my circuiting. You can make printed circuits. Another option is to use the breadboard to check the circuit and then transfer the components to printed circuit boards which match the breadboards. These are also available from Radio Shack (276-170, about $3.50). Using breadboards tends to be messy because of all of the jumpers. The neatness depends on how much time you want to spend cutting and training wires. The output section with the transistors is the same circuit repeated for each output channel. Color coding of wire can help keep track of the wiring.
I apologize for the lack of detail in the photo. It is the best I can do for showing the whole assembly with the pixel restrictions for uploading. I know you cannot follow the circuiting. I have identified key components to give an idea of the layout.
The small lower breadboard is temporarily connected to LED bargraphs for checking the output of the decade counter. The outputs from the pins of the decade counter are connected to the LEDs in the bargraph in series with 1K resistors to ground. Since transistors are used to drive the LEDs in the optoisolators, the LED bargraphs can be left connected if desired.
For the project described later, we need two controllers which count to five. Each controller needs 5 outputs(Q0 through Q4). Both can probably be squeezed onto the same two breadboards. I have shown only one. To make the decade counter count to 5, a jumper is placed from pin 1(Q5) to pin 15(Reset) of IC CD4017. Be sure pin 15 is disconnected from ground. Pin 13 remains grounded. Note the outputs are labeled Q0 thru Q9. The count is Q0, Q1, Q2, Q3, Q4. The instant Q5 receives the count, the count is reset to Q0.
The middle breadboard contains the 555 pulse generator and the CD4017 decade counter. These are circuited according to the schematic diagram except for the jumper modifications mentioned above.
I use the upper breadboard as sort of a patch panel in addition to holding the output transistors. The outputs of the decade counter (Q0 thru Q4 are jumpered to the base of each transistor through a 100K resistor. Upper and lower rows of holes on the breadboards are the V+ and Ground connection points respectively. The collector of the transistor is connected to V+ through a 1K resistor. The points of connection for wiring to the optoisolators are from each transistor emmiter to ground.
I use flat modular telephone cables from the output transistors to the SSR boxes. The cable arrangement is described under the steps on SSR boxes. The cables enter my house through boxes on the outside of the house and pass through conduits over a workbench where the controllers are located. I solder short lengths of 24 gauge wire onto each of the wires in the cable and insulate the solder joint with heat shrink tubing. The short wires are compatible with the holes in the breadboard. It is important that the wires connected to the optoisolater LEDs never accidentally touch any of the V+ voltage on the breadboards or they will be burned out.
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