daughter's gemmy puppy

[mdmedlin]

I bought my daughter one of those singing moving puppies made by gemmy last christmas.  She didn't like it and she tried to break it's ears off whenever it started singing.  The puppy bends forward, wiggles it's ears and sings jingle bells.  So like any good SoR member, I took it apart.  I am new to the whole robotics thing and I was hoping that I could maybe get some ideas of pieces and parts to use.  First thing I did was take off the speaker so I wouldn't have to hear it sing that stupid song over and over again.  It looks like it has 3 dc motors.  The motors have capacitors soldered to them.  The board that controls everything has a bunch of caps, resistors jumpers transistors.  I am guessing that all those put together make the dc motors work.  There is one chip that I think is the program chip.  It is encased in some black something or other.  So what I was wondering is, can I hack into the chip?  I don't think it is a programmable chip but I could be wrong.  Can I make a chip of somesort that will make the motors do what I want them to do.  I have not looked into a dc motor tutorial, but I will after I get done with this post.  Why are there capacitors on the motors?  I don't have a schematic of the board so I don't know what else you would want to know.  I do know that I have heard people talk about needing drivers for dc motors.  Was I misinterpreting them?  Could I solder something to the board that controls the motors and the speaker?  I am guessing that I would need inputs from a microcontroller.  Any ideas would be appreciated.  Thanks

[Soeren]

Hi,

You will most likely have to pull the existing control board and replace it entirely. What you pull goes into a drawer or box to become a stripper (nooo, not that kind, shame on you ) for spare components.

The caps on the motors are in place to kill noise generated by the motors.

You cannot hack into a "blob"-covered IC, if that's what you've got (it's likely a mask programmed chip).

If you want to control the motors you could build a microcontroller board, program it and use it as an replacement to the existing board.

Drivers for the motors can be simple or complex, depending on what you need the motors to do. A simple one way rotation only takes a single transistor, while bidirectional rotation need an H-bridge (i.e. 4 transistors minimum).

You might get more answers if you posted some close up photos of the electronics and the motors and perhaps a shot next to something of an internationally known size, showing the size of it all.

[SmAsH]

you probably wouldn't be able to hack the chip as these companies reduce prices of their electronics by using chips that only have the number of outputs they need and can only be programmed once. i think that black stuff may be some kind of heatsink?
ps: your daughter is cool...

[mdmedlin]

hehe thanks Smash, I'm kinda partial to her also, I will try to take a picture and get a close up, the bridge is probably what is on the other board as all three motors are bidirectional.  I figured that I would keep the caps on the motors if I pull them off for later use.

[SmAsH]

is the black thing on top of the chip like a blob of something that looks like dried up liquid?
and rather keep the caps on the motor as they help smooth the movements.
awaiting pics

[mdmedlin]

The first picture is a pic of the "blob" then I took one of the underside of the board so you could see how it is soldered in.  If I was any good at wiring diagrams I would draw you one, but I am not alas and alak.  I also did an over head and one next to my machinist scale so you can see what the scale is.  The board is about 2 inches long.  What I was thinking is that if I could figure out the wiring diagram, then I could jumper leads from a mocrocontroller to this board to control the motors, is that feasible?  I guess it would be more feasible if I could give you a wiring diagram and then you could tell me what goes where LOL.  The two yellow wires come from the push button that tells the thing to turn on and off.  The red and black wires are from the battery pack.  The other wires are from the motors.  Each motor is soldered into one side of a capacitor.  The weird thing is that when I touch one of the leads from the battery pack to one of the outlets of the motor, the motor spins, but not the 5v from the battery.  I measured the voltage at that contact and I get about 2.7 volts.

[SmAsH]

ok, first up the "blob" is a kind of heat absorbing protectant that is placed over most ic's in cheapo toys...
if you have access to an oscilloscope you can probably find out which trace goes where, but i doubt that...
how many motors are there?

[mdmedlin]

There are 3 motors and I am sure I could figure out what trace goes to what motor, I can trace the... traces.. LOL.  I am just not sure of what all the resistors, caps and transducers are for.  The cheap wiring from the factory keeps pulling out, so I have to either replace the wires or solder them in properly LOL.  So, if I know what trace goes to what motor, will that enable me figure out how I can use this board in future projects? Should I just desolder the cheapo ic and toss it and use the board for future projects?

[SmAsH]

i doubt you can use the board for future projects but you could probably use the parts anyway...
by transducer do you mean transistor?
what i meant by see what trace goes where was so you could see what is the output etc..
those transistors are most likely used as a motor driver as a normal ic cannot handle that amount of current.

[madchimp]

If you have a multimeter and patients you can probably figure out which traces from the board with the black blob go to which motor. If you figure that out you could probably pull that board with the black blob and carefully solder wires where it once hooked up and use the main board to drive the motors. I have a toy that I'm turning into a bot that has a similar configuration. Now it doesn't look like the transistors on your board are enough for anything but the motors hooked up already, it might work to drive a small bot or maybe something else that doesn't require a lot of power. Worse case scenario you draw too much power and cook the board and then toss it aside and then either build or buy a better motor driver. But for now I say reverse engineer it and use it.

[SmAsH]

just attach a gearbox and were good to go...
if it has a common gnd place one on there and see....

[Razor Concepts]

That blob is most likely just a chip-on-board sound playing chip, it's only purpose is to make sounds.

[SmAsH]

then what controls the motors?

[Razor Concepts]

The rest of the components on the board. It sounds impossible but it's doable.

[mdmedlin]

The motors themselves are pretty strong.  I grab ahold of a couple of them and it takes a little bit of strength to get them to not move.  I figured that if they were strong enough to withstand my daughter beating on them, then they are pretty good motors.  thanks for the advice I will trace out where the motors hook up and keep that in mind when I reverse engineer it.  I wont be doing any of that anytime soon as I need to first take the time to figure out how and what I am going to use the motors for.  thanks for all the advise

[SmAsH]

anytime mate!