Start up: Building a power supply
Before we start building a two dimensional printer, we will need a power supply to energize the electronics and motors we are going to use. We could use a supply that plugs into the wall, but it is far more convenient to use batteries for our experiments. Here is a picture of the power supply we will make. It is made of 4 "C" Cells, tie strip, switch, resistor, LED, and an output block. This will supply about 6 volts with enough capacity to run all the projects we have planned in this unit.
STEP 1 Soldering
The first step is to cut wires to connect the parts on the board. Use a diagonal cutter to snip the wires. Study the picture above and measure three red wires, two black (or blue) wires and one green wire that will make the connections as shown.
Strip a quarter of an inch on each end. See the video below to see how to use a diagonal cutter and stripper:
Our next step is to prepare for soldering. Soldering is a process of welding wires and contact together with a liquid tin/lead metal alloy. Solder comes in many forms, but most typically as wire:
Solder melts at a relatively low temperature for a metal (350-550 degrees). You can examine a piece of solder and note how flexible and bendable it is. Inside the wire is a core of "flux"--a special compound that helps the solder flow when it is melted. This kind of solder is called rosin core. We melt the solder with an iron:
Plug in the iron to warm it up. Make sure the hot end of the iron rests on a stand so that it does not burn the table. CAUTION! Soldering irons can easily burn the skin or burn through wire insulation. Always arrange your iron in a position that the metal parts of the iron do not touch anything that will melt or burn.
(Irons like this are used to do wood burning and if you want you can try it out by burning your initials onto the power supply board!)
Clean the tip of the iron before any use. To do this, wet a small sponge with water and then touch the tip of the iron to the sponge.
Start using your soldering iron by "tinning" some wire. See the video below to see how:
Once all the wires are prepared, solder the wires to the battery holder as shown in the photo and the diagram below. If you don't know how to solder, watch the video below the picture and diagram before starting to solder.
Step 2 . Testing the Supply
Once you have completed building the power supply, insert the four "C" cells (if they are not already in your battery holders). Make sure the direction of the cells match the images on the bottom of the holders. Turn on the switch and the LED should light. If it does not, you have one of several problems:
• The wiring is incorrect--check the diagram
• The LED is backwards--the short lead should be pointed toward the black or negative side of the battery
• C cells are improperly placed in holders
• Switch leads were not connected properly--see the diagram showing that the center connector and only one end connector of the switch are used.
Check these potential problems and if you still can't get the LED to light, seek assistance.
When the light goes on that means you have power, so next check the voltage. Find your multimeter and follow the directions in the video below:
Once the voltage has been determined, it is time to try out the supply. You can learn more about motors by taking this detour.
Now that you have a working power supply and know something about voltage and current, you can start on a two dimensional printer. Move on to Mechanics of a Plotter.