I designed this Experimental Shield for the UNO to give the beginner student both a useful learning environment as well as a versatile platform for various experiments and projects. If it is used in a classroom environment, all students can have identical, and fully functional interface circuitry to their UNO. Time can be saved as the need for poking wires and components into a wiring breadboard is eliminated (and troubleshooting of wiring errors is also eliminated). This shield features a green and red LED, a 7-segment display with decimal point, an 8-bit shift register for the display, 3 push-button switches, a toggle switch, a variable resistor, and an accurate 60Hz timing signal. All these components are pre-wired and ready to go. Students can focus on developing sketches and learning programing fundamentals and principles. The versatility of this shield design also allows for the creation of interesting projects and demonstrations without the need of a solderless breadboard.

I intended the Experimental Shield to offer lots of options for the experimenter and/or new UNO student. Beginner sketches that simply blink an LED are implemented on the same output 13 as on the UNO board itself. Likewise, more challenging sketches can incorporate an interrupt, perform PWM dimming, and display numerical values or even a message such as “HELLO”.

Knowledge of how to deal with a shift register can be very useful. The on board 8-bit shift register I incorporated into the design interfaces with each of the 7 segments of the LED display plus the decimal point. The display segments can be illuminated in any combination or pattern to show numerical digits, or alpha characters or anything else. Thus, the display can be used in creative ways to show digital information, text, or display interesting patterns. See the worksheet included in the Technical Information file.

There are also two LEDs, one red and one green, that can be turned on and off as part of a simple “first sketch”. They can also be used to demonstrate dimming by implementing (PWM) pulse width modulation on their associated outputs (pins 13 and 3). Three momentary push buttons and one 2-position toggle switch are provided as input devices. The on or off status (HIGH or LOW status) of these can be used to make decisions and change what a sketch does. A variable resistor provides an analog signal that can be adjusted up and down by turning the knob. This can be used to modify PWM values or change some type of function over a numerical range from 0 to 1023 instead of the digital binary 0 or 1 condition. I included a highly accurate 60Hz timing signal that is derived from the 12-volt AC power input. This is a somewhat unique feature that can be used to count AC cycles and thus determine seconds, minutes, and hours. When combined with the 7-segment display and the push buttons, it is possible to create an accurate digital clock or a stopwatch.

The full schematic diagram and parts list is provided in the attached documents for anyone who may want to build this shield. If you have experience and soldering skills, it can be built using the Proto Shield Rev3 available from the Arduino store. Also available (upon request) is the PC board layout I created for this shield.

Please contact me if you are interested or have questions or comments. LThomas3002

EXPANDED TECHNICAL DETAILS

All-In-One Prototyping Board

This "Master Shield" eliminates the need for messy breadboards by integrating common sensors and actors onto a single PCB.

• Standard Components: Includes a 10kΩ Potentiometer, RGB LED, Passive Buzzer, LDR, and DHT11.
• User Inputs: Features three momentary tactile buttons with pull-up resistors, allowing students to immediately start coding menu systems or interactive logic without wiring errors.

Educational Utility

• Simplified I/O: Each component is hard-wired to a specific Arduino pin (e.g., Buzzer on D5, LDR on A0).
• Development Speed: Ideal for workshops and rapid classroom lessons, this shield allows learners to focus 100% on the software logic and C++ fundamentals of the Arduino framework.