remote activated sprinkler valve

singularity · Posted: 09/01/2007 0:29 AM Post subject:

parts:

1) cheap 1 channel r/c car ($15 at KB Toys)
2) 5v relay (something like this should work)
3) sprinkler valve (with solenoid)
4)a standard diode ( this will work)
5)two 9v battery clip (go to radio shack or take them from broken stuff)
6)assorted batterys
7)antenna wire (i used 20ft of enamel coated 26 gauge because it was green and blended well)
8)assorted bits of wire

tools:

dremel
wire cutters
multi meter (this is absolutely essential)
soldering iron

....part one : disassembly....

take off the r/c car body, then use the dremel to cut the forward section of the car off. next remove the motor from its housing and unsolder the two wires going to it, now cut off the rear section of the car using the dremel. all that should remain of the car is the battery compartment, a small switch, and the circuit attached to the battery box. i have provided a diagram with the before and after of this step

...part two : re-wiring....

*note: i have written this part assuming you have acquired the same or very similar model r/c car as i used*

if you are using the same model car as i am then you will notice as soon as you turn on the car it should start moving backwards in circles, if we do not fix this as soon as we turn on the "detonator" the device will fire becuase any voltage forward or reverse can activate the relay. this is why we need the diode (diodes only allow current to flow in one direction) but before we solder the diode we are going to need to know which of the motor leads to solder it to. this is very simple to determine... turn on the r/c car do not touch the remote and use the multi meter to measure the voltage coming out of the wires which used to connect to the motor. if there is a minus sign on the screen switch the multi meter leads until it disappears then solder the diode (backwards) to the positive lead then turn the car off (when the multi meter is reading a positive voltage it would be the wire the red lead is touching) while you were reading the voltage of the motor you should have noticed something it was only 3v this will not activate our 5v relay (for obvious reasons) this is also very easy to fix. if you look at the battery box you should see there are three sets of wires connected to it (instead of the usual two)what you need to do here is find the positive 3v wire and connect it to the positive 5v lead on the box (again you need to use the multimeter but you do not need the car to be on) after this is done there should only be two sets of wires connected to the battery box.

...part three : wiring....

most of the hard stuff (if you would even consider it that) is done now all we need to do is connect the relay and 9v batterys. first solder the wires that used to connect to the motor to the coil side of the relay. next solder the 9v battery leads in series then connect one of the wires to the switch side of the relay and the other to the solenoid. lastly connect the remaining solenoid wire to the remaining switch lead on the relay.and thats pretty much it just connect up an antenna and your done. heres a basic diagram of what you should have when your done

...the remote...

the remote in its stock form will work just fine the only reason i put mine in a cell phone was to give it that "terrorist effect" it was designed to be used in airsoft games and i am known for using AKs (considered a "terrorist weapon" by most) so i thought it fit nicely. to get it to fit in the phone i shaved off part of the circuit using a dremel then wired the forward button to the end button on the cell phone key pad. lastly i modified it to run off a car key fob battery (which is significantly smaller than a standard 9 volt)

...other info....

this is a very basic r/c circuit it is prone to picking up interference this was designed to be used in the woods acting as a remote detonated mine. you must remember that this cannot be used in a modded sprinkler valve unless you bough a separate solenoid valve to pilot the sprinkler valve (like a small 1/4 npt solenoid valve or something). if the device goes off as soon as you turn on the power switch that means the diode was inserted the wrong way this is simple to fix just unsolder it turn it 180 degrees and solder it back in. this is a relatively weak r/c receiver, in my mine it is paired with about 20ft of antenna which would normally be wrapped around a nearby tree giving it an effective range of over 100ft. if you plan on using this underground (in the case of my mine) encase all the electronics in hot glue so they are not damaged by water. one last thing is if the device seems to detonate randomly if its not interference its the antenna... make sure the wire coming in contact with the circuit boards antenna lead doesn't make a metal to metal contact just keep the insulation on it

if anything doesn't seem clear just ask