RFID based shopping cart

[geethucmohan1992]

edited. deleted

 

[panic mode]

1. URDC shown in power supply unit connected to J2??
yes, you bring external DC power to J2, it's voltage need to be more than 8V, so 9-15VDC will be example of reasonable power source


2. What is J1 in power supply unit? Is it the transformer secondary?
yes, it is connector to bring AC power to the circuit


3. In the reset mechanism whats 100E?
100 Ohm resistor

4. In the reset mechanism whats SW1?
reset push button ("switch" but momentary)

5. Is j3 the buzzer connection?
yes

6. why is there an LED in the power supply unit? What is the name of the same?
LED5 is green (G) LED to indicate that you have power.

7. From where do we get the ground for power supply as well?
all GND symbols are to be connected... they are drawn separately to reduce clutter and crossing of lines / wires.

8. What does the arrows near the microcontroller mean?
which one, there are two microcontrollers and is few dozens of arrows...

9. What is the base1 at pin 20 of microcontroller U2?
i don't know but i guess it is the GND connected to mounting pads so unit base acts as ground for the circuit.

10. Is crystal oscillator available as such for buying?
i think so:
https://www.digikey.com/scripts/dks...cts=0&ptm=0&fid=0&quantity=0&PV139=29&stock=1


11. Why is the battery circuit below LCD2 needed? where is it connected?
to provide power when AC power is no longer available so microcontroller will not power off and loose memory


12. How is the vegetable tray connected?
normally trays are standalone scales which are mounted as part of counter and interfaced to register through RS232 for example. but in this case i see label "To Port 0" which is 8 ch. analog port of the microcontroller U2.


13. Why does it say vegetable tray to port 0?
probably because used scale has analog output(s) too which simplifies interfacing.

14. Rfid card trolley and rfid module shown by an arrow, why is that, what is that?
RFID is "radio frequency identification" and it is used similar to barcode scan to identify product for example (unlike barcode scan, there does not need to be line of sight between tag and reader).

15. how is the rfid module connected?
it is not shown

16. why is rs232 (page 18) needed?
why is RS232 ever needed? to send data from one device to another. this circuit seem to have a need to exchange data with another device (PC, microcontroller, whatever...)



17. why is the transmitter (mo sawr ask transmitter) and reciever (os-rx 02 ask reciever) needed? where is it connected?
where do you see that? it is not on the same page or i don't see it.


18. Motor control ckt is not shown. How is it connected?
it is not shown. only one pin is used but it still could be many things:
- relay to turn on motor if it always runs same way,
- transistor if the motor speed is to be changed using PWM for example,
- PWM driving servo (this can move back and forth using variations in duty cycle).
etc.


19. Driver IC has to be connected. circuit?
driver...? motor driver? sure...


20. which are the stock box parts and the trolley parts?
no clue, i am not going to read some 40 page document for you


21. how is the load cell connected?
depends on a load cell (where is your part number?). most of the load cells are full bridge, but all of them, also some already have integrated interface. usually this is not the case so "naked" load cell without amplifier etc. needs excitation circuit and differential opamp to produce analog output proportional to applied load.


22. How is data send recieved by the computer (centralised billing system)?
seem to be RS232 i(P3.1/TxD, P3.0/RxD)


23. How is the computer connected to the circuit?
see previous point (22).