This is a relatively inexpensive and easy to build project that will help you test out all of your Arduino projects and prototypes. Since it has a plug-in power source, it eliminates frequent battery use and leaves the breadboard free of voltage regulators and capacitors providing more room for projects. However, if you need battery power instead, the Prototyping Center also has the option of switching to 9 volts of battery power. Additionally, this prototyping center will have room for a soldering iron and "Third Hand" soldering tool so everything you need will be at your fingertips. The Prototyping Center will give you access to chose from 9 volts, 5 volts (perfect for Arduino prototyping), and 3.3 volts.

A soldering Iron, cordless drill, coping saw, wood glue, hot glue gun, X-Acto knife, and wire cutters are needed.

Step 1: Materials

I bought most of the components from Jameco and Tayda Electronics. Tayda is a good choice when buying resistors, LEDs, chrystals, switches and other small, cheap components. I always purchase the more expensive parts from Jameco such as breadboards, integrated circuits, and power supplies. I purchased the wood needed for the base of the project and the acrylic sheet from Lowe's. Altogether, the cost of the electronic parts should be under $100. The wood and acrylic should be under $15.

1. Plenty of Resistors: Any from 100-500 Ohms should be sufficient. (I bought most of mine from Tayda)
2. Large Breadboard:
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_20723_-1 (Like me, if you want a bigger breadboard to work with, consider buying two of these to put together.)
3. Small Breadboard:
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_20601_-1
4. LED's: (At least one red, one blue, and one clear.) http://www.taydaelectronics.com/leds/led-5mm-blue-water-clear-ultra-bright.html
5. Wire: (I bought wire from Jameco)
6. 7-segment LED Display: (6 are needed for this project) http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_24782_-1
7. 2.1mm Wall Adapter: DCU090050E2961: JAMECO RELIAPRO: Power Supplies & Wall Adapters
8. Breadboard Power Supply: DFR0140: DFROBOT: Education & Hobby Kits
9. 9V Battery Connector: http://www.taydaelectronics.com/9v-9-volt-battery-clip-connector.html
10. Connectors: Cable mount: 08-65-0805: MOLEX INC.: Interconnects Headers: 22-29-2021: MOLEX INC.: Interconnects Housing: 22-01-2027: MOLEX INC.: Interconnects
11. Magnet Reed Sensor: MP201701: CHERRY CORPORATION: Electromechanical
12. Switches: Mini Toggle Switch SPDT On-Off-On
13. Wood (Bottom: 1x3x8): Shop 1 x 3 x 8 Kiln-Dried Whitewood Softwood Board at Lowes.com
14. Wood (Top: 1/4x2x2): Shop 1/4 x 2 x 2 Birch Plywood at Lowes.com
15. Acrylic Sheet: Shop OPTIX 10-in x 8-in Clear Acrylic Sheet at Lowes.com
16. Glue: Both wood glue and hot glue.
17. Rubber Feet: BS01RCL10X20RP: JAMECO VALUEPRO: Electromechanical
18. Small Magnet: I just found one lying around but here's a link to some small rare earth magnets from Jameco: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2181319_-1

If you don't already have one, here's the link to a Third-Hand Tool from Jameco: 3RD HAND: JAMECO BENCHPRO: Test, Tools & Supplies

Step 2: Building the Base

Refer to the 2nd picture to get an idea of where each hole should be cut.

1. For the top of the base of the prototyping center I cut out a 2x1 foot sheet of the plywood. The upper left-hand corner was cut out for the soldering iron.
2. To display each of the three voltages, two of the 7-segment LED displays must be hot glued together (for example, in one pair, one display will light up "9" and the other "V" forming a single display that shows "9V"). Make sure the hole is cut big enough for the leads of both LED displays to fit through. When measured put together, the 7-segment LED displays are 0.75x0.75 inches. Using a drill and coping saw, cut three holes just under 0.75x0.75 inches so that the displays will rest on top of the wood surface. However, make sure to cut the holes big enough so that the display's leads will fit through the hole.
3. Below each of the holes cut for the three displays, drill a hole for the power supply header. Again, make sure the hole is small enough so that the component rests on top of the wood but big enough so that the leads fit through the hole.
4. Near the bottom of the base, or wherever you chose to put them, drill two holes for the switches. (I drilled three because I have an extra switch for an LCD screen I will use in a later project.)
5. Also, cut a long, thin hole just below where the small breadboard with the power supply will be. This will allow wires from displays and LEDs underneath the base to reach the voltage on the small breadboard.
6. I decided to put a light just to the left of the smaller breadboard for extra lighting when soldering. You can use a clear LED but I found a broken part of an old LCD screen that worked perfectly as a lamp.
7. Drill a hole about an inch to the left of where the 9V header will be. This is where the wires of the magnet sensor will come through (see picture 3).
8. Finally, drill two holes in the top right hand corner of the base. These will be for the LEDs that light up the acrylic display. You might want to wait to drill these holes until after the bottom section of the base is glued on.

After you finish cutting and drilling all the holes for the top of the base, begin measuring and gluing on the bottom pieces. Follow picture 5. Place the rubber feet under each corner of the base. This will give it a strong grip to the work surface.

Step 3: Acrylic Display

I added this "display" simply for its looks. It shows when the power has been turned on and when you have switched from plug-in power to battery power.

1. I began by cutting a small piece of acrylic from the sheet (I used a metal-cutting saw).
2. Using an X-acto knife, carve the ON/OFF symbol on the right side of the acrylic piece. Quarters and dimes can be useful as guides when carving the inner an outer circles. On the left, I carved a small, simple symbol of a battery and power plug.
3. Using the hot glue gun, glue two small pieces of wood to the front and back of the bottom of the acrylic "display." This will direct the light from the LEDs in the base up through the acrylic.
4.Position the "display" over the two LEDs making sure that they light up the symbols well and glue it in place.

Step 4: LED Displays

These 7-segment LED displays will be glued together in pairs to display the different voltages. The first will display "9" on one display and "V" on the other so that it displays 9V. The second pair will display 5V and the third 3V. Refer to the display's data sheet to wire them correctly. The types I use have common cathodes. Picture 1 shows the pinout of the display I used.
Make sure the wires are long enough enough to reach the power supply before soldering them to the displays, headers, and LEDs.

1. After gluing together the displays, solder one wire to connect all positive pins that display "9" and "V" (shown in picture 2). Connect both ground pins with one wire as well. Use the diagram to see which leads to solder to display the number of volts and the "V."
2. After all the connections are made and tested, glue the three displays to the top board (see picture 6). You may need to use a small piece of wood to strengthen the display's connection to the top board.
3. Solder a red and black wire to two (the 5V and 3.3V) of the three headers that will be glued below its respective display. Put the wires through the holes and glue the two headers in place. Make sure the positive lead is on the right and the negative lead is on the left. For the third header, solder the wires of a 9V battery holder to the two leads (be sure to put the wires through the holes first).

Step 5: Add the Breadboards

The smaller breadboard will be used to transfer the power from the wall power supply to the rest of the board. The larger breadboard will be used for prototyping. I attached two breadboards together to provide more room for larger projects.

1. Plug the Breadboard Power Supply into the breadboard. The power rail on the left of the breadboard will be 5 volts and the rail on the right will be 3.3 volts. Jameco sells their breadboards with double sided tape on the bottom. Stick the smaller breadboard on the top board just above the thin hole cut for access to the wires (see picture 1).
2. The larger breadboard should be placed just beneath the three voltage headers.
3. Use the housing connector and some wire to create a way to transfer the voltage from the headers to the breadboard (see picture 3). Cut two small, flexible wires and connect them from the connector housing to the breadboard power rails. To connect the wires in the housing, use pliers or a crimping tool. Glue a small magnet to the end of the connector housing so that when it's plugged into the 9V header it comes very close to the magnet reed sensor (see picture 3).

Step 6: Lights and Switches

1. Lamp: For extra lighting, you can use a high intensity, clear LED as a lamp. I used an LED light from an old LCD display and copper 24 AWG wire for stability. The lamp should be connected to the power through a switch placed at the bottom of the base (see step 7 for basic schematic).

2. Display: For the acrylic display, glue a blue LED in the right hole and a red LED in the left hole. The red LED should be connected to 5V through a resistor and the magnet reed sensor (see step 7 for entire schematic). When the small magnet on the connector housing comes close to the reed sensor, it will complete the circuit and 5 volts will flow to the red LED.

3. Switches: Fasten the switches through the holes drilled in the bottom of the board. One switch should be connected from the power to the lamp and the other from the power to the three voltage displays (see step 7 for a basic schematic).

Step 7: Wiring

Here is a basic schematic of the wiring. The values of the resistors depend on how bright you want the LEDs to be. I found that the red LED needed a lower resistance than the blue LED so that it could match the blue LED's brightness. For the LED lamp, I decided to make it as bright as possible. I used a 100 ohm resistor connected to the 5V power rail (this may be too much current for a regular LED).

Step 8: Test and Finish

Use a multi-meter to check all the connections and the voltages.

This project is not only fun but it's also functional. It's much easier to work on other projects when you don't need to worry about batteries and making space on your breadboard.