Hi everyone, I found a ‘music toy’ which I think is for kids, with a couple of buttons, three LEDs and a speaker.


Manufacture technology

The wires and chips or metal are connected by soldering. The whole manufacturing process of PBC board is:


The plastic casing is made by injection molding or slush molding.

At last, assemble everything.

Part numbers


I think the part number is hj-051-1c, but I have trouble with finding a match on datasheet.


screwdriver & cutter

Design elements

1.As you can see from the image down there. The keys on the outer surface of the toy can be pressed from all four directions. But the interiors work in a completely different manner. There is one button inside which, when pressed on the right side for example – connects the circuit on the right. This completion of the circuit results in a particular song being played. This essentially means that there is one conductive button inside which plays all four songs.



2. Another element is switch.


Ummm, I really don’t know how to arrange my words shortly. The switch is very simple but a little bit tricky at the same time. If you want to know, come to me, I can explain it to you 🙂


Project 1: Teardown

Your first assignment is to take apart an electronics object and document it. Some ideas of things and places to find them:

  • talking kids’ toys at the dollar store or Target
  • an old CD player you have around
  • your old cell phone or digital camera
  • pick up something good at the Gowanus e-waste warehouse

Battery powered devices are best, as are ones that play sound, light up, and have buttons. Item’s that aren’t quite complicated enough for this project:

  • hair dryer
  • headphones
  • most kitchen appliances like toasters

Select something that’s easy to get NOW, do not order anything online for this project. Do not select something that is dangerous to take apart, like a CRT monitor/TV.

You will be evaluated based on the following guidelines:

  • Take lots of well-lit photos during the disassembly process
  • Consider taking video as well (optional but encouraged, consider timelapse)
  • Photograph all the parts spread out on a table in some kind of order (consider knolling your parts)
  • Identify the materials used for each component
  • Identify the manufacturing techniques/equipment used to make it
  • Look up part numbers on chips and find out what they do (searching the part number + “datasheet” helps)
  • Make a list of the tools and techniques you used to take it apart
  • Select two design elements that interest you and describe why you think the designer made it that way

Your assignment will be turned in as a blog post here (in the Teardown category) titled something like “Speak and Spell Teardown” where “Speak and Spell” is substituted for the name of your object. Your post is due by 8pm Wednesday 9/20.

For inspiration:

Screen Shot 2014-09-04 at 1.11.41 PM

Here’s my first teardown from 2006, much simpler than the one’s you’ll turn in but hopefully encouraging anyway!

Tear apart a toy cellphone by Teng


The whole body is made of plastic and the keyboard is made of rubber, the main assembling way is using screws, and some of the parts locked together,the most interesting part is the ball in the center of four keys,it will hit on a button which on the circuit board when you push it, but there’s no reaction when you roll it. The reason why designer do this is because the press button is pretty common on children’s toys, but rolling ball button is not common and kids can explore the feeling of rolling and pressing at the same time.the rubber keys give you a good touching feelings. and one more interesting parts is the rubber keys, they touched more soft than the side key and light keys, kids can get different feelings when they tough the keys on the toy. the light keys are made of PVC plastic, the other parts I’m not sure. but design for kids should be safe.

MacMini : tearDown


This macMini was bound for the e-waste collection but first made a pit stop at my workbench so that I investigative and tear it down. My intent was to learn about how this compact computer was engineered, how dissimilar materials are used, how are parts joined together.


The first place to begin is to locate the main chassis screws that hold the shell together. Normally, the screws would be directly visible in the back of the device or concealed under some kind of rubber bumper or pad on the bottom. I peeled back the bottom pad and found nothing ! Was this going to be a tedious process like solving a master-level puzzle ?


Knolling : the top surface and side chassis. Galvanized steel sheet has been laser cut or stamped and then brake-formed for the top and bottom panels of the macMini. The steel serves 3 major functions; to strengthen the injection molded plastic panels, to create clips for fastening the sub-assembly to the aluminum chassis, and an integrated safety switch. If the plastic top panel is removed for repair or service, the neutral path of electricity is interrupted and prevents the unit from powering up.

I wanted this to be a non-destructive process as if I was a repair technician and i quickly learned that. . . . . YES ! this IS a masterful puzzle to completely disassemble. The example below is from the disc drive mechanism that pull the disc in / out of the chassis.

hidden-access-infoSTEP 1 : rotate metal piece to expose the white plastic part below.

STEP 2 : slide the plastic part back and forth.

STEP 3 : notice or identify that there is an access hole only when the part is in a specific position.

STEP 4 : remove the screw that holds this component.



In addition to standard and custom mechanical fasteners, there were many cleverly concealed means of joinery like  CLIPS, TABS, RIVETS, SPOT WELDS, and some that I’d call mortise and tenon. The engineers wanted to use minimal screws for aesthetics for the exterior of the MacMini but why did they use so few screws on the interior? Do screws take up more time in manufacturing and assembly or are there other ways to solve fastening?

Instead of using 4 screws to hold a part, there would be one or two used in conjunction with tabs, clips or tenons. I found that neighboring assemblies would hold one-another in place. What can we call this methodology. . . . screw sharing?

wire-conduitCreating something that is brilliantly simple often requires more effort.

The injection molded ABS plastic internal chassis was engineered to serve many functions ;

• a skeletal structure that holds the hard drive, most of the PC boards, and the fan.

• integrated ducting to circulate cool air around the device.

• integrated wire conduits, wire clips, and acts as double insulator protecting electrical wires from areas of increased heat.

I was delighted to find that the DVD drive was filled with good old mechanical components used to actuate motion like springs, hinges, motors, gears, linear actuators, and worm shafts.


VIBRATION control : what a delight to discover that the audio speaker was isolated from the chassis with medium density rubber which allows the music to bump/bump and sound clear at high decibel.


PART IDENTIFICATION : Throughout the teardown, I thought about reusing some of these fascinating parts in a future Arduino project, like the LED board. In order to understand how to use it, I search ElectronicProducts.com and discovered how every part is specifically called out including the material, manufacturing process and physicality. The wire harness, mounting bracket, connector, and the black foam rubber pad (die cut w/PSA) are all specified. Below is how just the PCB assembly was called out;

  • Location- LED PCB Assembly
  • Function- Mechanical / Electo mechanical
  • Component Family – Electro mechanical
  • Component Type – PCB
  • Quantity – 1
  • Manufacturer – OKI
  • Part Number – NA
  • Component Description- 2 Layer – FR4
  • Markings- 0507, 01-01003029-00, HH. LED BOARD, CK66 94V-0
  • Form- NA
  • IO / Pin Count- NA
  • IO Pitch- NA
  • Diameter (mm)- 10.45
  • Length (mm)- 8.70
  • Height (mm)- 0.50
  • Data Sheet Links- Visit URL

LED board.jpg

SUMMARY : similar to reverse engineering by way of a 3-dimensional schematic, this was an exciting and fascinating activity. I realized that heat must be a major factor in the considerations of designing a compact and powerful computer evident by the insulators, sinks and the distribution and air circulation. There were far more mechanical systems than expected in a digital machine and if the CD drive were to disappear, it would eliminate two motors, about four assemblies composed of up to 28 parts and save on space and the use of lithium grease for lubricating the plastic gears and slides, totaling over a hundred pieces. The MacMini was made to be repaired with exception to a few blind rivets used in the hard drive’s axis and the individual components soldered to the PC boards.

The disassembled MacMini quickly laid out.


Further research may include;

• electromagnetic interference EMI that is created by the device / how the MacMini was designed to shield from the EMI of other components such as a wireless keyboard and monitor.

• identifying the manufacturing processes used, including assembly and disassembly.

• creating a resource, use and waste list to understand the life cycle of this product.

• part list : calling out the size, material, manufacturer and function of each part.

• composing a step-by-step guide to disassemble and reassemble this device.

Cheers !

Chris Rand








This simple toy is my subject to teardown. Powered by AAA batteries it involves a rotatory motion and lit LEDs when a button is pushed.

The initial unscrewing yields the inside of the toy.


Taking out the useful part from the casing shows a button, 5 LEDs,small circuitry,a motor and connecting wires.


Exploring each section separately, the lighting component of the toy is shown. Consisting of 5 LEDs connected in a simple circuit.The only use of the circuit board is powering the LEDs,which are soldered to the board with wires.


The Pushbutton type switch is used to operate the toy.These switches complete the flow of electricity when they are pressed. When a pushbutton switch is in the on position, a spring inside the electrical device makes contact with wires that will allow the current to flow. Then, when the switch is pushed down again, the spring inside retracts, and this stops electrical current, deactivating the device.


For the rotary motion, the toy uses a brushed DC motor.


The final layout is shown as,


The tools used in this operation are,



Part-Manufacturing Technique

Head- Making a mould and casting

Body- Making a mould and casting

LED Lights- A semiconductor wafer,multiple wafers are joined to become a semiconductor,Ultrasonic process to clean it.

Electrical components- Include highly detailed intricate processes,although very cheap to make.

The one design choice I like is the simplicity of the button placement. Very child friendly and surprisingly sturdy.