Day 12: Learning by breaking

Until 3pm today I was busy running errands and fulfilling other responsibilities. That put me in the mood to tear up stuff. I have a whole bunch of electronic products lying around the house that have been decommissioned because of this or that reason, and all I had to do was pick one.

I chose my Sharp robotic vacuum cleaner. In 3–4 short months it had started to produce a lot more noise than Mei and I found acceptable (since we run it mainly at night), and its battery life was down to about ten minutes, so we shoved it aside. Today it met its un-maker.

I took a lot of pictures throughout the process and took some notes (scroll down to see).

Here’s what I learned by tearing apart the Sharp robotic vacuum cleaner

Tidiness is the order of the day

Wires that run through the body are always bundled together with heat shrink tubing or some fabric tape. As they wind through the inside of the product (ie. its enclosure), they are held in place by thoughtfully placed ribs that are created during the plastic moulding process

Unused holes

Not all holes in the JST clip are used. Quite a number have more holes than are utilised. Probably to do with keeping inventory small by reusing parts for other products, either in the contract manufacturer’s factory or the brand’s own factory.

So many (custom) parts!

There are easily 20 specially moulded plastic components that I found in the product, from as big to the product’s plastic enclosure (two halves) to something as small as a black strip that holds another slim, transparent plastic light-diffusing strip in place. Preparing for production must have cost millions just for tooling, considering how metal moulds for injection-moulding typically costs upwards of $20,000 SGD each.

This is why entrepreneurs, especially those indoctrinated by Silicon Valley’s ideas, mostly remain in the realm of software. When I was in Founder Institute in Singapore, my cohort consisted of 95 percent software founders and only 5 percent working on hardware. It is an expensive game!

Designed with assembly in mind

Rod that holds another component in place goes through two through-holes in the moulded plastic enclosure. One has slightly wider diameter than the other. During assembly, the rod easily enters one half, then through the component being held (in this case, the rod holds the wheel hub), and finally enters the tight-fitting hole. Assembly worker then just needs to hammer to fix the component firmly in place.

Also, all connections to motherboard PCB are done along peripheral of the board for organisational leanness. Also easier for assembly worker to tell which JST socket attaches to which peripheral PCB.

As I noticed little things like this I pictured an assembly line worker doing one or two specialised task before handing it off to another worker downstream. Workers are not stupid, but if you have seen the internals of a large product like the robotic vacuum, you would realise that it can get confusing fast. Consistency in assembly from components is critical to the product’s proper functioning. There are so many tiny electronic components on each PCB and so many connections from one board to another and to other parts that one minor mistake can have mission-failure level consequences. Debugging hardware is like finding a needle in a needlestack!

I also think that this might be the section in the long process from idea to the customer’s hands that most entrepreneurs on Kickstarter overlook, factoring too little money for little (but lethal) mistakes. There is very little margin for error for hardware entrepreneurs.

A few questions I have for hardware pros

• What is this component? (black with three legs and half dome)

I found three of these in the product — one perched atop with a plastic prism above it, and two at the front of the robot along the bumper. They are definitely sensors of some kind. Probably not ultrasonic since there were 6 of those already. Help me out if you know!

• What can I use the various PCBs (including the motherboard holding the processor) for now that I have torn them out? Can they be reused wholly? Or should I attempt to desolder the valuable components and throw out the rest of the board?

• I threw away the charging device before today’s teardown. Is it still possible to use the lithium ion battery salvaged from the bot?

That’s it for today’s post. Off to watch Zootopia!