Wow! A 12V DC motor, a hardy air compressor, a pressure transducer, an LCD screen with an LED backlight, a multi-purpose LED flashlight, and a human interface to set the desired pressure setting... all for about $30?! Again, wow! Oh yeah, it also comes with a handy carry bag!
Mini air compressor's listed features. Image courtesy of Amazon.
This mini air compressor, by Suaoki, to my surprise, is actually quite heavy (1.8 pounds). Sure, its housing is made of plastic—high-quality plastic, by the way— but, given the purpose of this device (generating and pumping high-pressure air) and knowing that it uses a DC motor, the fact that it weighs a lot suggests that it is comprised of robust and high-quality internal parts. We shall soon find out! But first, let's first review its technical specifications:
- Power input: 12VDC
- Maximum pressure: 100psi
- Maximum current: 10A
- Inflating from 0 to 35psi: 6.5 mins
- Pressure gauge display: Reading is PSI, Bar, kPa
- Working temperature: -10°C to +65°C
- Three-mode lighting (flashlight): 7x LEDs
- 4x white: used for illumination
- 3x red: flashes for warning, or SOS
- Accessories: 2 adaptors for inflatables
- Electrical cable length: 2950±100mm / 9.7±0.3 feet
- Air hose length: 470±50mm / 1.5±0.2 feet
- Net weight: 0.85 kg / 1.8 pounds
- Dimensions: 180.5 x 158 x 67.5mm / 7.1 x 6.2 x 2.7 inches
Mini air compressor—all four sides.
Mini air compressor and carry bag.
We Begin the Disassembly
After removing about eight screws and unpopping some plastic pieces, I was able to "look under the hood" to see all the internal components. I was very pleasantly surprised to see a large metal—not plastic—motor, two rather heavy-duty metal—again, not plastic—gears, and a metal piston rod that drives the air compressor. I also spotted two PCBs, a pressure transducer for measuring the air pressure, and two robust buttons. Now I know why this device is as heavy as it is.
Major internal components
Continuing the Disassembly
After the removal of a few more screws and after some pulling, a little pushing, and some wiggling, I was able to separate the plastic housing from the internal components (see the figure below).
Internal components separated from the plastic housing.
- The pressure transducer, used for monitoring the air pressure, has no visible markings.
- The DC motor has markings but nothing discernible.
- The two robust buttons have markings of: SW-3-2 5A/40A 250V.
- We'll discuss the two PCBs and the LED flashlight in more detail below.
The figure below identifies many of the components on the PCB dedicated to the LCD display.
- All the intelligence of this system—"the secret sauce"—has been locked away by use of epoxy.
- The Atmel IC (ATMEL602) is an I2C serial EEPROM memory device.
- The three buttons correspond with the "M", "+" and "-" external buttons.
- The elastomeric connector—also known as a Zebra connector—is used for electrically connecting the LCD screen to the PCB.
- The LCD's backlighting LED is actually quite bright! Let's see if you can find it in the figure below... let there be light!!
There's not too much involved with the design of the other PCB. It includes a few general purpose diodes (M7), and some NPN (J3Y) and PNP (2TY) transistors and current limiting resistors for controlling the red and white LEDs.
The relay/switch—rated at 10A/6A 250VAC—is used for turning ON/OFF the DC motor.
LED and motor control PCB
The seven LEDs consist of four white LEDs and three red LEDs. While the white LEDs are either ON or OFF, the red LEDs have two modes: a slow flash, or an SOS flash.
Red and white LEDs.
This is a solidly-built and, what appears to be (based on the robust internal components) a highly-reliable mini air compressor. Again, I'm super surprised at its low asking price, given all its features and its tight fit-and-finish assembly and appearance.