We are huge fans of Shenzhen. One of the main reasons is the Hua Qiang Bei district. It is a compact area (5 square blocks) of buildings that are stuffed with shops and stalls selling all measure of electronics from components to computers. Navigating this Willie Wonka'esque array of electronics shops/stalls was overwhelming so we came up with a system. This system allows us to navigate the district reliably and return to shops we like without getting lost. This sounds like a simple task, however the scale of the area means that this was no mean feat. We're posting all the details here and hopefully others might find it helpful when exploring.
All the details (including a google map layer can be found here):
- Easy to solder. (only 15 components)
- Great tool to help make your own boards.
- Open source design. (CC-BY-SA)
More Details (HERE)
We use these servos for all sorts of things. From the trigger on our 'internet connected kettle', to the striker on our 'bell of notification'. They are easy to interface with an Arduino, not too expensive, and rugged. Given how much we rely on them we thought it was a perfect candidate for our first product teardown.
Interested in more teardowns? 'About Teardowns'
.:Summary:.Product: Standard Servo
Made By: Spring RC
Made In: Shenzhen, China
.:Taking Apart:.To take the servo apart remove the four screws found on the bottom. This allows the top and bottom plastic housing to slip off revealing the gear train on top and the circuit board on the bottom. The PCB and motor requires some convincing to be removed. Finally if you want to fully disassemble the servo you need to remove some hot glue that holds the potentiometer in place..:What's Inside:.The servo is assembled from three plastic housings; a gear train (explored in more depth below), a PCB with motor and potentiometer (explored in more detail below). Plus two red rubber rings, which give the servo it's unique red stripe appearance..:Interesting Bits:.Gear TrainThe gear train has 5 gears (2 single and 3 double). These go from the motor (metal 10 teeth) --> first double gear (60 teeth to 11 teeth) --> second double (49 teeth to 11 teeth) --> third double (35 teeth to 13 teeth) --> output gear (42 teeth). These combine for a total gear reduction of 274.75:1.PCBThe PCB is single sided and easy to read. The large chip is a servo decoder (KC2462). This takes input from the signal line (white wire) and compares it to the position of the servo (given by the potentiometer). The chip then produces a control output based on the error between the two values. The output signal is fed to 4 transistors (Q1-4) which are configured in an h-bridge (this allows the motor to be driven either direction). This simple closed loop system causes the servo to always be moving towards the desired position. (We'll delve deeper into how this PCB works and the parts used in a future post).:Sources, Helpful Links, Mentioned Products:.How a servo works (wikipedia)How an H-bridge works (wikipedia)Standard Servo (oomlout.co.uk)TeenyTurner Precision Screwdriver (oomlout.co.uk)
(want to take a closer look, all images are available on Flickr Servo Teardown Photos (CC-BY-SA))
When making a decision to stock a product we often take it apart. In the past we've told ourselves this is to inspect build quality but recently we've realized this was just a cover. We like knowing what's inside something, taking it apart and figuring out how it does what it's designed to do. We thought (hoped) that others may have the same feelings so decided to start documenting these inspections. Below you will find a list of what we've taken apart. (will be updated as we publish more teardowns).
It's an open secret that Shenzhen (China) is the center of the consumer electronics world. It's a treasure trove of electronics manufacturers, markets and know how. However it can be a daunting place to explore, which is why we're super excited about the hacker workshop being put on by Dangerous Prototypes.
It's a three day intro to the city with some pretty amazing elements.
A tour of the electronics markets in Huaqiangbei.
Time with some of Shenzhen's local hackers.
What promises to be a truly great (2 day) soldering class at Shenzhen's "Cell Phone Repair School".
We'll be attending and if you can find any excuse recommend you do too.
Full details (Shenzhen Hacker Camp Mini Site)
(apologies for the over use of 'amazing' and great' we're just really excited)