Simple Simon’s SparkFun Mod

No, wait. That’s not right. I meant to say Simple SparkFun Simon Mod!

In this busy holiday season, it’s rare that we get the time to even write an article let alone build a kit. But this kit is such good clean fun we had to do both! Across our desk slid the diminutive red box with the unmistakable SparkFun logo. The SparkFun Thru-Hole Simon Kit – cool! We’d been looking for a Simon game at a reasonable price for some time. Seems it was discontinued at some point and skyrocketed in value due to it’s new status as a collector’s item. Well it’s not worth THAT much to us so we just let the Simon dream die out. Until now!


The Original Simon Game from Milton Bradley

Fig 1 – The Original Simon Game


Basically this is a super-simple kit that uses an Atmega168 to emulate the game of Simon. Aside from the micro, there are only two decoupling caps, one resistor, the LED’s and battery clips to solder. It only takes 15-20 minutes to build even if you’re screwing around and playing with different setups. Here’s the official SparkFun pic of the kit as well as a slow-mo pic of the modified kit in action.

The Official SparkFun Simon Kit Pic A Pic of the modified Simon Glowing Brightly in the Night


Fig 2 – The SparkFun Simon Kit Fig 3 – Our Modified Kit in Action

Now before we get into the build info, let me say again that the kit is awesome and easy to build. But there are a couple of things that had to be improved.

  1. Mounting the batteries on top makes for an awfully uncomfortable user experience, always getting in the way and slowing down the high-speed monotony of the game. Also, the only grip you have is on the buzzer on the bottom and that’s not symmetric.
  2. The LED’s are not marked and there is no information on the color order. (probably to avoid copyright claims or something) But for Simon enthusiasts this is very annoying, as well as the fact that the tones are probably incorrect – ack!
  3. Moving the batteries to the bottom is blocked by the bad location of the buzzer. In an ocean of free space, it happens to be placed right in the middle of the battery.
  4. The LED’s are driven directly from the micro port. A little bit of cowboy design, shooting from the hip because the designer is smart enough to know he can get away with it based on the battery voltage and since the LED is not on continuously. But for people just learning electronics, it’s really not good to teach them risky design techniques. LED’s must be current limited to avoid overstressing the mosfets in the micro’s port. In this case, we get away with it but resistors should be used.
  5. The micro isn’t socketed. We socketed ours and generally believe that unless you’re running at 20MHz or above, components with more than 4 or 6 leads should be socketed. Why? In case you ever want to remove it! Didn’t you know that tiny gremlins will reverse your power supply or do other things to try to get novice builders to blow up their IC’s. Or they will charge you up on a cold winter’s day and try to get you to kill your micro’s ports with an ESD zap. And in all these cases, a 2-cent socket saves you the long tedious process of 28-pin desoldering. Unless you’re a Heat Gun Desoldering wizard, of course.


OK, OK. Down off the soapbox and let’s look at the actual mod.


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