[Spider!]’s contribution to the pantheon of paintball markers is the SMAC: a unique revision to one of Airgun Design’s ever-popular Automags. We needed our tipster, [Russell] to provide some context on the Automag’s evolution, because the brand has served as a popular hacking platform for nearly 20 years. The most frequent is a “Pneumag” modification, which converts the original, fully-mechanical trigger pull into a version where the trigger actuates a pneumatic cylinder to fire the gun.
According to [Russell], the Pneumag’s trigger must completely release between each shot to properly recharge the firing chamber. Without a full release, the gun can load extra balls into the barrel and lead to gloppy consequences. Electronic controls solve this problem, but [Spider!] favored an analog solution that captured a “less is more” mentality over a pre-fab microcontroller board. He built the circuit around a 556 timer used as a delayed re-trigger, but with a few modifications.
Swing by [Spider!]’s forum post for additional details, a cluster of pictures and a bill of materials. Microcontroller alternatives? We’ve got you covered.
Many of the robots we feature here are driven by some sort of microcontroller, whether it be an Arduino, Launchpad, Picaxe, etc. Rarely do we see a robot however, using analog circuits to perform higher-level functions typically relegated to those more complex controllers. Instructables user [hasn0life] built such a robot recently, which he entered into a contest at his college. After hearing about the 555 design contest from a friend, he tweaked his project and created a wall-following robot using a 556 timer.
The robot is fairly simple when you take a close look, though that does not take away from the elegance of his design. A single IR sensor is used to detect objects in the robot’s periphery, guiding the robot along. When the robot gets too close to a wall, one wheel reverses, pulling the robot away. Once the robot has moved a sufficient distance, the other wheel is reversed in order to straighten out the robot. Then, both wheels work in concert to get the robot moving forward.
Take a look at the video below to watch the robot navigate its way around his workshop, and if you are interested in learning more about analog robotics, check out this post from a few days back.
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