10.10.2012

Remote-Controlled Water Blaster

By Josh

One of the edgiest, most hacker-ish projects in UNBORED is the remote-controlled water blaster dreamed up by contributor John Edgar Park.

“Here’s the plan,” John writes. “We’ll strap the water blaster’s trigger into a permanently pulled position, and insert a remote-controlled relay switch into the power supply. At the push of a remote transmitter’s button, you’ll be able to start and stop the flow of electricity running between the battery and the motor that powers the water blaster’s pump.” What that means: You’ll be able to soak your friends and family while savoring the moment from a safe distance!

John explains how to splice the remote-controlled relay (a switch that is opened and closed by applying an electrical current) into the water blaster’s battery circuit. Then, he gives instructions on how to give the relay switch some power — using a soldering iron to splice a battery holder and a relay unit together. Finally, he gives instructions on testing and using the modified blaster.

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UPDATE: There were a few errors and unclear instructions in the “Remote-Controlled Water Blaster” article. Here are corrections!

PAGE 137

* Step 1: “Unscrew the blaster’s battery cover and remove the battery pack” should instead read “Open the blaster’s battery cover and remove the battery pack” [because not every battery cover needs to be unscrewed]

* Step 1: “the one connected to the coiled spring is the negative (–) tab, the other is the positive (+) tab” should instead read “the one connected to the coiled spring is the positive (+) tab, the other is the negative (-) tab” [this was a silly mistake, sorry!]

* Step 2: “Find the red 12V “voltage” wire on the relay switch; it connects to the positive terminal. (The black wire is the “ground,” which connects to the negative terminal.)” should instead read “Find the 12V OUT wire on the relay switch (your colors may vary from the photos); it will contact the positive tab. (The GND OUT wire is the “ground,” which will contact the negative tab.)”

* Step 2: “Use the wire strippers to remove 1″ of insulation from both the red wire and the black wire” should instead read “Use the wire strippers to remove 1″ of insulation from both of these wires.”

* Step 3: “Cover the positive (+) end of one of the dummy batteries with the exposed red voltage wire” should instead read “Cover the positive (+) end of one of the dummy batteries with the exposed 12V OUT wire.”

* Step 3: “Cover the negative (-) end of the other dummy battery with the exposed black ground wire” should instead read “Cover the negative (–) end of the other dummy battery with the exposed GND OUT wire.”

* Step 4: “make sure the exposed voltage wire is touching the positive (+) terminal” should instead read “make sure the exposed 12V OUT wire is touching the positive (+) tab”

* Step 4: “make sure the exposed ground wire touches the negative (-) terminal” should instead read “make sure the exposed GND OUT wire touches the negative (–) tab”

PAGE 138

Under POWER THE RELAY SWITCH

* Step 2: “section of heat-shrink tubing over the relay unit’s red voltage wire” should instead read “section of heat-shrink tubing over the relay unit’s 12V IN wire”

* Step 3: “Twist together the ends of the battery holder’s red voltage wire and the relay unit’s red voltage wire” should instead read “Twist together the ends of the battery holder’s red voltage wire and the relay unit’s 12V IN wire.”

* Step 6: “Repeat the above steps to solder together and insulate the battery holder’s black ground wire and the relay unit’s black ground wire” should instead read “Repeat the above steps to solder together and insulate the battery holder’s black earth wire and the relay unit’s GND IN wire”

Phew!

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The photos shown below are of John’s son, getting blasted via remote control. Nice!