I want to record my sound for the start here robot. birdmun suggested getting one of those greeting cards that you can record your voice on (10 seconds) and it plays it back.
I bought one such card.
Now, I want to know how to safely connect it to my start here robot. Birdmun says i need transistors and resistors (i dont know what to do). He says i need to replace the switches with a pair of transistors and a resistor for the base of each transistor.
Can someone please help me? I will post a picture of my module if needed!
I don’t really know exactly how these cards operate. I’ve seen them before but never inspected them with hacking in mind. A picture/vid would be awesome (for me, anyway).
I’m not sure what birdmun planned with two transistors (amplifier for the low pin output?) but this is what he’s talking about:
Rb is the current-limiting resistor. Depending on what your doing it can keep the transistor from turning into Blue Smoke. There are many better explainations than what I can tell you (and calculators) all over the web. IIRC you will not need one <look around at the experts >
The protection diode is not necessary. It is for inductive loads like motors or relays.
Your load is the greeting card module. Find which end of your card’s switch is positive voltage and which is ground and wire it into the circuit appropriately. This is assuming it is a simple SPST momentary that closes the contacts when the card opens. You need to verify that to be certain. I’m just guessing how it works.
If you are not using the card’s battery, +Vs needs to be the voltage that the card module likes. Don’t necessarily just feed 5V from your PICAXE board straight into the module. You might end up making Smoke. If you use the battery be sure to tie its ground to the robot’s ground or nothing will work either.
Calculon has hacked these sort of things before both with and without transistors. There are two easy ways to do it:
If the toy has more than one function and more than one switch (eg Yak Back or Radio Shack recorder module):
Find the switch that activates the thing. Is it a pushbutton, or a pull-switch?
The switch will connect the chip (the black lump) with either positive or ground (usually ground). Find out which.
Solder a 10k resistor to the copper plating on the “chip” side of the switch. You can use a wire instead of a resistor, but Calculon has found that hacked toys have a very short lifespan, and he thinks a resistor will help, especially if the switch is positive.
Connect the other end of the resistor to your PicAxe.
Repeat steps 1-4 for each button or switch on the toy.
Power the toy. If the toy uses less than 5 volts, you’ll want to power it seperately from the Axe, and share a ground. If the toy uses 4 to 6 volts, you can just power it from the Axe.
Activate the buttons by having your PicAxe either go high or low (depending on the toy). This simulates the switch being activated.
If the toy only has one function:
Find the switch that activates the thing.
Jam it closed in whatever way works best for you. Calculon just removes the pushbutton and solders the two halves of the switch together so there is no longer a switch.
Connect the toy’s negative lead to the Collector pin on a 2N2222 transistor. Connect the picaxe to the Base pin, and connect the Emitter pin to ground.
Connect the toy’s positive lead to a voltage source appropriate for the toy. (make sure the toy and the picaxe share a ground).
Go high on the picaxe pin. This activates the transistor, which pulls the current through the toy, making it do its thing.
I’d like to help but I have no idea what I’m looking at. What’s going on with that stuff on the PCB? More pictures of that thing would be helpful. Are one of those things dangling off a switch? Is it the silver thing on the lower right hand side of the board? A battery has to be in there somewhere…
Top left: is in the top left of the first image, Top right: is in the lower left of the first image, Bottom right: is in the lower right of the first image, Bottom: is diagonally up and left of the lower right, Bottom left: is left of the Bottom image.
I would guess the round silver objects are batteries, the Bottom image is one of the switches, and the Top right image is another switch. Macro photos will help identify these parts more readily.
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