Play ‘Simon’ Schematic Circuit Diagram

The electronic game Simon comes in the form of a large, round console with four red, green, blue, and yellow illuminated buttons. These buttons light up in a random order with longer and longer sequences, accompanied by musical notes. The object of the game is to reproduce these sequences precisely by pressing the buttons in the same order and the same number of times as they lit up. So apart from the entertainment value, this game also stimulates visual and aural memory.

You can use an ‘old’ Basic Stamp I to build your own ‘Simon’ game. It has enough input/outputs lines to drive the LEDs and read the buttons needed by the game. To simplify construction in practice, the illuminated buttons are reproduced here by associating a button and an LED of the same color connected to the same port.

The circuit is very simple, thanks to the Basic Stamp I, and above all the fact that its ports, P0–P3 in this instance, can operate as inputs, where they are used to read the buttons, and as outputs, where they are used to directly drive the LEDs. Line P4 is used as a output only to drive the loudspeaker that reproduces the musical notes that accompany the lighting of the LEDs.

The power supply uses a voltage bet ween 7 and 15 V, which can come from a 9 V battery, for example, since the circuit goes into standby automatically when not used.

For the loudspeaker, make sure you choose a miniature 50 Ω type. And as for buttons S1–S5, if you want to use our PCB design, you’ll need to use the square D6 type from ITT. These types also have colored lenses that are particularly useful here.

On the subject of the PCB, do note that the LEDs and buttons can equally well be fitted on the component or trackside, in order to make it easier to fit the circuit into a case. You can organize the layout of the LED and button colors however you like. However, it is important to wire each output (P0–P3) with an LED and a button of the same color, so as to respect the logic of the game. The program to be loaded into the Basic Stamp is available for free download from the Elektor website [1] as well as from the author’s own website [2].

The circuit has an automatic power-on reset, and you can force a reset at any time by pressing S1. Following a reset, the LEDs light up in turn to encourage you to play. If you don’t put in an appearance by pressing any button, other than S1, or course, after a few seconds the game goes into stand-by; all the LEDs go out and the consumption drops to just a few tens of µA.

To start the game up again, all you have to do is perform a reset using S1, or press any other button for at least 2 s. The game lights the first LED and plays the corresponding musical note. You must then press, within the next second or so, the button of the same color. Simon then lights two LEDs in succession (this may be the same one twice!) and generates the two corresponding musical notes.

You in turn then have to press the two corresponding buttons in the same order. The game then continues with a sequence that gets longer each time, up to the point where you make a mistake reproducing it. Simon makes a groaning noise to indicate the slightest error, ending the current round and starting another. Have fun!