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Wireless call buzzer

This project was intended to have a button or switch in one area and wirelessly
transmit to the receiver for 1 or 2 output options. We chose a 1 output, to a buzzer. We will also tell you how to wire up the 2nd output at the end. You can use a variety of things that will suit your need for the out put. A few options we thought may be interesting are a flashing LED, buzzer or siren, a pre-recorded voice or sound output, and a few more. Please note, some modifications may need to be made to your design for different output types as well as cosmetical looks and structural integrity.

Parts

• 600-0252 = Mercedes RC car
• 273-0059 = 12 VDC Piezo buzzer
• 270-0412 = 3 AAA battery holder
• 270-0408 = 2 AA battery holder
• 275-1565 = soft push on/off switch (2 if you intend to have 2 outputs)
• 278-0503 = 30 gauge hook up wire

You will also need:
• needle nose pliers or tweezers
• wire cutters and/or stripper
• set of precision screw drivers
• electrical tape
• solder and a soldering gun
• 3 AAA batteries
• 2 AA batteries

Steps

1. The first thing we did was do disassemble the Mercedes (60-252).
a). There are 4 screws that hold the body of the car to the frame, remove them first.
b). Next, remove the receiving antenna from the body of the car without cutting or damaging it. You will need to remove the 2 screws towards the rear of the car that are holding the lower lights in as well. The wire should come out of the hot glue fairly easy. the body/cover of the car is now useless.
c). Snip the black and yellow wires going to the front wheels. Note: the wire casing will slide off of the wire very easily, be sure to secures it so as not to get the two mixed up.
d). Do the same as above to the brown and blue wire leading to the rear motors.
e). Remove the 3 screws holding a black plastic cover over the circuit board and lift off.
f). Sever the connection between the battery compartment and board to allow for removal. We have no use for the rest of the car now that we have the circuit.
2. Next is taking apart the remote.
a). There are 2 screws and 2 plastic tabs holding this together. remove the screws. The tabs are on the top of the remote just push down. You may have to wiggle the 2 halves to get them apart.
b). One screw to take off here for the board.
c). Cut both the red and black wires leading to the battery section.
d). There is a slider switch wired in, remove this and connect the wires that were attached to it.
3. We’ll start with the more complex of the two sections. The board we removed from step 2 is what we will be using here.
a). Using the diagram shown below we determined that for one output we either need to choose forward or backwards. Note: this is not the same model chip as in our remote but it does have the same pin layout.

b). We chose forward, so pin 5. Take your 278-503 wire and cut about half a foot or so off. Strip both ends. Wrap one end around pin 5. Be sure that it is not touching any other pins before you solder it, as well as the solder does not hit another pin.
c). Now wire in the 270-412 battery holder to the red and black wires. Do NOT solder or tape the ground (black for those who don’t know) wire yet, as we will be hooking a switch up to it soon.
d). Take your 275-1565 soft on/off switch and connect the wire we have on pin 5 to one lead. Cut off another length of wire from your 278-503 spool.Take this new wire and put one end to the other lead on your switch, and the other to ground. You may now solder / tape this wire up.
e). The next part we didn’t go to much into detail on how it worked and were just getting it done the easiest way we could. The left joystick switch needs to be held down constantly, we chose to rubberband it to the down position. There are ways it can be dont so it looks and functions better, but this fit our needs. Yes it does seem odd that the switch is down and not up but it does work, trust us.
4. Now the receiver from step 1
a). The brown wire is going to be your ground while the blue is your power. We hooked up our 273-059 Piezo buzzer to this.
b). Now the battery leads. Closest to the wires we just hooked up is your power, the other is ground. Wire in your 270-408 2AA battery holder.
5. Add your batteries and your antenna. Average range of sending / receiving we have found is roughly 30 feet

Adding a second output

6. On the receiver, the yellow and black wires that were cut in step 1, are going to be your second output.
a). Pin 1 on your sending unit (the part from the remote), you will need to use some more of your 278-503 spool and do the same as in step 3b.
b). Tie into your ground on your sending unit with more of your 278-503 spool.
c). Take the wire you just tied into your ground hook into another switch of your choice or another 275-1565.
d). The wire you hooked up in 6a needs to be hooked up to the other lead of the new switch from step 6c.
e). Fasten the right lever on your sending unit to the left position, similar to step 3e
f). On the receiver unit, the black wire is going to be your ground and the yellow your power. You now have 2 outputs, congrats!