…quite possible the most complex thing I’ve ever built.

by Stephen Hobley on August 24, 2011

Post image for …quite possible the most complex thing I’ve ever built.

As part of the “Great Create” I was challenged by my buddies at Make magazine to complete a set of projects only using parts from Radio Shack.

For my first project they tasked me with reproducing the rather excellent 555-timer “Whack-a-Mole” game created by Jim Chen.

This one was tough… oh yes… very tough.

Eventually I had to abandon the idea of reproducing it on a breadboard like Jim – it soon became clear that it was going to be impossible to convey to anyone else how to do it, so I needed to try another approach.

I decided to recreate the design as a double-sided PCB – etched at home using a couple of single sided boards and some Ferric Chloride.

This worked out, but Radio Shack had one trick left up its sleeve – the PNP transistors that came in the multipack were *backwards* to the standard PNP footprint. Of course, I only realised it *after* I’d added them to the board.


But after I fixed that it worked! Yay!

…and here’s a video to prove it:

If you’re up to the challenge – the full instructions are over on MAKE : Projects –

click here to be teleported there right now

More projects to come…


{ 4 comments… read them below or add one }

Aaron August 25, 2011 at 7:13 am

Hitting autoroute in Eagle is hardly a complex thing. I think you may be underachieving here a bit.

Stephen Hobley August 25, 2011 at 7:22 am

You’re quite right, I think autorouting took about 37 seconds.

– but etching, aligning and bonding two planes using toner transfer, assembling the board by hand (soldering each wire on both sides) and ripping up a bunch of misplaced transistors – damaging and repairing tracks in the process – *is* the most complex thing that I’ve done.

I could of course just send it to an overseas fab house – but where’s the pleasure in that? 🙂

Mohamed September 10, 2011 at 10:49 am

amazing !!!

Zane Infinitum September 4, 2014 at 11:24 am

Good day sir. I saw your whac-a-mole inspired game on your blog. Thanks by the way sir for sharing it to us. If I may ask sir, how can I make the turning on of the LEDs faster? And it also says on your blog that CONT signal control kinda momentarily pauses the game until the lit up LEDs are turned off, what will happen if I removed the CONT signal control part of the circuit? Would the pausing of the game be disabled and is there any other effects it would do in the whole circuit if I removed that portion? Thanks in advance for the reply sir.

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