I am sure everyone of your have done payment through PayTM at a shop. Have you ever noticed there is a device at shop which tell the so and so amount is received when you make the payment?
No need to show that you have made the payment and shopkeeper also need not verify if payment got credited to their account.
A simple idea/solution which PayTM brought to the market. And now a days I have seen PhonePe Sound Box has also came to the market.
As an Engineer I was always wondering how they have build it, what electronics is involved. I was looking for PayTM Sound Box since long to teardown. Luckily I got to know that one of my friend Ravi had it which him and was happy to give me.
From outside PayTM Sound Box looks like this.
On the front panel, you see QR code sticker and both sides holes for sound to come out.
Bottom side, information like product name, model number input power rating, etc. is mentioned. It is BIS certified and INSPIRY China is the company who manufactured it for PAYTM.
Back side you see Micro USB Connector is provided for powering /charging the unit. It has internal battery.
On the side SIM card Slot is given with rubber protective cover.
Once you open the box by unscrewing, 1st thing you will see is a PCB where you see a SIM Card connector, 2PIn connector where single cell lithium cell battery is connected.
Vertical mounted MicroUSB connector, Resent button (just in case there is a hang issue), you can also see clearly two pair of speaker wires which are going to the speakers.
Antenna and GND pads are provided on the PCB. These pads connects to the antenna which is attached to the Enclosure and connects to these pads when the enclosure is closed, see the image below.
Battery is 2000mAh 3.6V Cell which is equivalent to 7.2 Watt-hour of energy when fully charged.
It was easy to remove the plastic which was holding two speakers in the front and on the back side was the main PCB.
You can see all the parts in the images below. Keys are also there with rubber gasket.
Now comes the most interesting part, the electronics hardware.
Other side of the PCB, you can see the Mediatek ARM processor MT6261A which is a GSM Processor is used in the design, it has all multimedia functions like mic, speaker, even SD Card interface(not used in this design). It is actually has all features which are required in a phone.
NOR Flash DS25M4AB-1AIB4 from Dosilicon is used for the firmware and other basic settings.
The RF front end implemented using a sperate chip with marking 5169 / NBANZ /1948N, I wasn’t able to get the datasheet.
External Audio Amplifier is also used Nsiway NS4158B.
On the PCB you can see four keys, two for volume up down and one for power and fourth one for mode.
You also see various test pads on the PCB like for JTAG interface, USB DM, DP, etc.
One RGB LED is also there to indicate various states during operation.
that’s pretty much all on the PCB.
I hope you found this teardown useful and learned something new today!
If you have any questions please ask in the comments section below, I will try to respond as soon as possible.
You can read other teardown blogs and watch teardown videos.
I am currently working as an embedded systems design consultant and helping companies build custom embedded products, develop test automation solution for their PCB or complete product.
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