Pet Tracking Device Design

Thought for 31 sec

flux

Yes — multiple cells in-line along the collar is a much better architecture.

Recommended battery topology:

Use parallel cells: 1S2P or 1S3P, not series.
That keeps the pack at the same safe single-cell Li-ion voltage range for the existing charger/SIM800L design.
It increases capacity while allowing cells to be placed end-to-end around the collar curve.
Each cell should have protection/fusing or a protected pack design, because parallel Li-ion cells need safe balancing and fault protection.

Runtime impact:

1× 3500 mAh cell: ~20.8 mA average available for 7 days — borderline.
2× 3500 mAh in parallel: ~41.7 mA average available — much safer.
3× 3500 mAh in parallel: ~62.5 mA average available — strong margin.
With the earlier conservative estimate around 20.6 mA average, 2 cells should comfortably meet 7 days, assuming decent cellular/GPS signal and proper sleep firmware.

Design recommendation:

Use 1S2P 18650 cells as the baseline.
Keep 5-minute location updates as default.
Keep SIM800L/GPS sleep modes mandatory.
Mechanically, distribute the cells along the collar and connect them with flexible wiring or a rigid-flex harness; do not rely on the PCB itself to bend sharply around cylindrical cells.

I still can’t save this into the project because your access is comment-only, but the electrical direction is now clear: 1S2P 18650 pack + 5-minute reporting is the practical baseline.

Use 1S2P baseline

Explain pack wiring

Add protection details

Optimize power design

Check manufacturability

please explain what J1 does.

geeckball

@copilot please explain what J1 does.

copilot

The component J1 in your schematic is described as a connector from JST Sales America Inc. It has two pins:

Pin 1 (Pin_1): This pin is connected to the VBAT net, which typically supplies power to components.
Pin 2 (Pin_2): This pin is connected to the ground (GND) net.

Given the use of J connectors, this likely serves as a battery or power input connector for your pet tracker design, connecting an external battery or power source to power the circuit. The specific type of JST connector isn't detailed here, but this family of connectors is often used in battery connections due to their secure locks and durability. If you need more detailed information about the specific JST part, you might need to refer to the datasheet or component documentation.

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please explain what U2 does.

guyan

@copilot please explain what U2 does.

copilot

Certainly! Let's analyze the details provided:

Component Overview

Designator: U2
MPN: NEO-6M-GPS
Manufacturer: U-blox
License: CC BY 4.0
Pins:

CFG_GPS0/SCK: Pin 16
EXTINT0: Pin 4
GND: Pins 10, 12, 13, and 24
MISO/CFG_COM1: Pin 15
MOSI/CFG_COM0: Pin 14
RF_IN: Pin 11
RSVD_17: Pin 17
RSVD_8: Pin 8
RXD1: Pin 21
SCL2: Pin 19
SDA2: Pin 18
SS_N: Pin 2
TIMEPULSE: Pin 3
TXD1: Pin 20
USB_DM: Pin 5
USB_DP: Pin 6
V_BCKP: Pin 22
VCC: Pin 23
VCC_RF: Pin 9
VDDUSB: Pin 7

NEO-6M-GPS Module

The NEO-6M-GPS from U-blox is a standalone GPS receiver module that is used for acquiring and tracking GPS satellite signals, and it provides location information, such as latitude, longitude, and altitude. Here's a summary of its key functionalities and usage:

GPS Signal Reception:
- RF_IN (Pin 11): This pin is connected to the GPS antenna to receive signals from GPS satellites.
- VCC_RF (Pin 9): Provides power for the RF signal processing internal to the module.
Power Pins:
- VCC (Pin 23): Main power input for the module.
- GND (Pins 10, 12, 13, and 24): Ground connections.
- VDDUSB (Pin 7): Power input for USB connectivity.
- V_BCKP (Pin 22): Backup power supply for RTC and module configuration retention.
Communication Interfaces:
- UART:
  - TXD1 (Pin 20): Transmits data to a microcontroller $e.g., location data$ .
  - RXD1 (Pin 21): Receives configuration commands from a microcontroller.
- I2C:
  - SDA2 (Pin 18): Serial data line.
  - SCL2 (Pin 19): Serial clock line.
- SPI:
  - SCK (Pin 16): Serial clock.
  - MISO (Pin 15): Master In Slave Out.
  - MOSI (Pin 14): Master Out Slave In.
  - SS_N (Pin 2): Slave select.
USB Interface:
- USB_DM (Pin 5): Negative USB data line.
- USB_DP (Pin 6): Positive USB data line.
Control and Status Pins:
- EXTINT0 (Pin 4): External interrupt input, used for waking up the module.
- TIMEPULSE (Pin 3): Provides a time pulse output $e.g., 1PPS - 1 pulse per second$ .
- CFG_GPS0/SCK (Pin 16): Configuration and clock pin.

Key Functions of U2 in the Pet Tracker:

Location Tracking: U2 is responsible for receiving GPS signals and determining the current location of the pet.
Data Communication: It communicates the location data to the STM32 $U4$ via UART $TXD1 and RXD1 pins$ . This data might then be processed or forwarded to the SIM800L $U1$ to be sent over a network.

This module plays a critical role in ensuring that the pet tracker can accurately determine and relay the pet's location.

If you need more specific information on how to interface with this module or about its internal workings, please let me know!

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please explain what U2 does.

ziondido

@copilot please explain what U2 does.

copilot

Absolutely! The component U2 in your project is a NEO-6M-GPS module manufactured by U-blox. Here's a breakdown of what this module does and its role in your pet tracker design:

NEO-6M-GPS Module Key Features:

GPS Reception: The NEO-6M-GPS is a GPS receiver module that provides location data to the microcontroller by receiving signals from GPS satellites.
UART Communication: It communicates with the STM32L4 microcontroller via a UART interface.
Integrated Antenna: The module can support an external antenna through the RF_IN pin for improved signal reception.
Backup Power: It can use a backup battery to maintain the time and satellite data, allowing for quicker fixes.

Pin Description:

VCC (Pin 23): Main power supply input.
GND (Pins 10, 12, 13, 24): Ground connections.
TXD1 (Pin 20): Transmit Data for UART communication.
RXD1 (Pin 21): Receive Data for UART communication.
RF_IN (Pin 11): Input for the external antenna.
VBCKP (Pin 22): Backup battery input for faster acquisition.

Connection in the Project:

Power Supply:
- Connect U2:VCC to [Net 25](@design 25) (3.3V rail).
- Connect U2:GND to @design net.
UART Communication with STM32L4:
- Connect U2:TXD1 to STM32L4:PA3 via [Net 13](@design 13) (GPS_TX).
- Connect U2:RXD1 to STM32L4:PA2 via [Net 5](@design 5) (GPS_RX).
Backup Battery:
- Connect U2:VBCKP to BT1, and make sure it also has the proper ground connection.

This module is essential for your pet tracker design, providing the location data that the STM32L4 microcontroller will process and send to the server through the SIM800L module.

If you need more specific details or have any particular questions about how to integrate or configure the NEO-6M-GPS module, please let me know!

Someone is typing...

Check that none of the unconnected pins require pull-up or pull-down resistors t...

ziondido

@copilot Check that none of the unconnected pins require pull-up or pull-down resistors to ensure proper function.

copilot

Let's review the design to identify unconnected pins that might require pull-up or pull-down resistors for proper functioning. We'll specifically look at the STM32L4 MCU and any peripheral devices connected to it.

STM32L4 Microcontroller STM32L442KCU6

PA0 – PA15: Ensure no floating pins, as they can cause erratic behavior.
PB0 – PB7: Same considerations as PA pins.
PC14, PC15: Typically used for oscillator; ensure they're handled appropriately.
PH3: General-purpose I/O pin.

Connections

PA2, PA3, PA9, PA10, PA13, PA14: Connected as GPS_RX, GPS_TX, SIM_RX, SIM_TX, SWDIO, SWCLK (no pull-up or pull-down needed as they are connected to other components).

Peripherals

NEO-6M GPS: Check for any configuration pins that might need pull-up/pull-down.
SIM800L: Ensure pins like RST, TXD, RXD are managed correctly.
24AA32A-I/ST: EEPROM, check SDA and SCL lines.

Steps:

Unconnected pins on STM32L4: Verify no floating input pins. Add pull-ups or pull-downs if necessary.
GPS Module: Ensure no configuration pins like CFG_GPS0/SCK are left floating.
SIM800L: Check RST, TXD, RXD, and other control pins.
EEPROM (SDA, SCL): Typically, I²C lines need pull-up resistors.

Let's identify specific signals and confirm the appropriate pull-ups or pull-downs:

STM32L4:
- PA0 through PA15 and PB0 through PB7: Unused GPIOs should either be configured as analog mode or have pull-up/down resistors in place.
- NRST: Already managed.
GPS Module (NEO-6M):
- CFG_GPS0/SCK: Needs to be checked.
- Other pins seem connected as per the schematic.
SIM800L:
- RST: Needs to confirm proper handling (connected to SIM_RST net).
EEPROM (24AA32A-I/ST):
- SDA and SCL: Typically require 10k pull-up resistors for proper operation.

Let's summarize the required connections:

STM32 Unconnected GPIOs (Hypothetical):

PA0, PA1, PA4-PA8, PA11-PA12, PA15, PB0-PB7: Consider configuring as analog mode or with pull-up/pull-down resistors if left unused.

GPS Module:

Connect CFG_GPS0/SCK to GND or VCC (based on configuration).

SIM800L:

RST (Reset pin): Connected properly to SIM_RST net.

EEPROM:

Connect SDA to 3V3 via 10k pull-up resistor.
Connect SCL to 3V3 via 10k pull-up resistor.

For exact implementation in your schematic on Flux, you can add resistors or simply configure the unused pins accordingly.

If you need, I can help you design the specific connections. Do you want to review or add these resistors to your flux project?

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explain this project.

hadiel

@copilot explain this project.

copilot

This project is a Pet Tracker Reference Design that uses an STM32L4 microcontroller to track a pet's location and communicate with a network via a SIM800L module. Here's a breakdown of how the main components work together:

Key Components:

Microcontroller (U4: STM32L442KCU6): This is the brain of the tracker, responsible for processing and controlling all functions. It interfaces with the GPS and cellular modules.
GPS Module (U2: NEO-6M-GPS): Provides location data to the microcontroller via a UART interface.
SIM Module (U1: SIM800L): Enables cellular communication, allowing the pet tracker's location data to be sent to a server.
Power Regulation (U5: AP2112K-3.3TRG1): Provides 3.3V to the rest of the circuit from the main power source.
Battery Management (IC1: MCP73831T-2ACI/OT): Manages the charging of the battery $BT1$ .

Connections:

Power Supply:
- The system can be powered via USB $J3$ or from a battery $BT1$ .
- The 3.3V regulator provides a stable voltage supply to components that require it.
Communication:
- The STM32 MCU communicates with the GPS module using UART. Connect $U4$ (PA2) to $U2$ (RXD1) and $U4$ (PA3) to $U2$ (TXD1).
- The SIM800L module is connected to the STM32 via UART for communication. Connect $U4$ (PA10) to $U1$ (TXD) (Net 15) and $U4$ (PA9) to $U1$ (RXD).
Peripherals:
- An EEPROM (U3: 24AA32A-I/ST) is connected to store data, interfaced via I2C with the STM32.
- LEDs (LED1 and LED2) are used for indicating the status of the system. They are connected to suitable GPIO pins on the STM32.

Additional Information:

Ground (GND): Common ground connections for the entire circuit to ensure all components are at the same reference voltage.
There are some nets used for connections, such as the reset line for the MCU and SIM module, provided there are appropriate lines like Net 16 (for SIM_RST).

This design combines location tracking capability with communication functionality to ensure the pet's location can be reliably transmitted to a server, providing real-time tracking. If you need further details on specific sections, feel free to ask!

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please explain what U5 does.

geeckball

@copilot please explain what U5 does.

copilot

The component U5 in your project is an AP2112K-3.3TRG1, which is a low dropout (LDO) linear voltage regulator manufactured by Diodes Incorporated. It provides a regulated output voltage of 3.3V. Here are some details about its functionality:

Input Voltage $V_{IN}$: The input voltage range typically needs to be higher than the regulated output voltage, considering the dropout voltage. For the AP2112, the dropout voltage is quite low, allowing for efficient regulation.
Output Voltage $V_{OUT}$: Provides a steady 3.3V output, which is used in your project to power various 3.3V components.
Enable Pin $EN$: The regulator will only output 3.3V when this pin is driven high. It allows the regulator to be enabled or disabled to save power when regulation is not needed.
Ground $GND$: Provides a reference point for the regulator and relates to the system ground.

This component plays a crucial role in managing power for the circuits by ensuring a consistent 3.3V output for stable device operation. It's connected to several components in your schematic that require a 3.3V supply.

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how much does this project cost

alejovicente

@copilot how much does this project cost

copilot

To estimate the cost of your project, we need to sum up the prices of all the components used in the design. Based on the available list of part numbers in your project, here are the main components with their approximate prices:

SIM800L: $8.29
NEO-6M-GPS: (Price not listed)
TYPE-C-31-M-12: $0.16
AP2112K-3.3TRG1: $0.08 (average)
24AA32A-I/ST: $0.50 (average)
FTSH-105-01-L-DV-007-K: $2.68
ML414H IV01E: $1.43 (average)
STM32L442KCU6: $5.97 (average)
MCP73831T-2ACI/OT: $0.71 (average)

For parts without a listed price, you might need to get quotes directly from suppliers or consider using placeholders for an estimate. Let's sum up the cost for the parts with the prices mentioned:

\text{Total Estimated Cost} = 8.29 + 0.16 + 0.08 + 0.50 + 2.68 + 1.43 + 5.97 + 0.71 = \$19.82

Keep in mind that this is a rough estimate and doesn't include additional costs like shipping, taxes, and potential component substitutions due to stock availability. If you need precise costing, you should check with distributors for the current pricing and availability.

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create a high level mermaid block diagram of U4. Include key component's manufac...

mamduuuuuu

@copilot create a high level mermaid block diagram of U4. Include key component's manufacturer part number in each block whenever possible.

copilot

Sure, here's a high-level Mermaid block diagram for the STM32L442KCU6 (U4).

Diagram

sher516362

show

ystar

explain full connection

Someone is typing...

list all the parts used in this schematics along with its designator

geeckball

@copilot list all the parts used in this schematics along with its designator

copilot

Here's a list of all the parts used in the schematic along with their designators:

GPS Module: U2 $\text{(NEO-6M-GPS)}$
GSM Module: U1 $\text{(SIM800L)}$
MCU: U4 $\text{(STM32L442KCU6)}$
EEPROM: U3 $\text{(24AA32A-I/ST)}$
Voltage Regulator: U5 $\text{(AP2112K-3.3TRG1)}$
Battery Charger: IC1 $\text{(MCP73831T-2ACI/OT)}$
Inductor: L1 $\text{(22 µH)}$
Capacitors:
- C1 $\text{(10 µF)}$
- C2 $\text{(10 µF)}$
- C3 $\text{(4.7 µF)}$
- C4 $\text{(4.7 µF)}$
- C5 $\text{(1 µF)}$
Resistors:
- R1 $\text{(1 kΩ)}$
- R2 $\text{(1 kΩ)}$
- R3 $\text{(22 Ω)}$
- R4 $\text{(5 kΩ)}$
- R5 $\text{(5 kΩ)}$
- R6 $\text{(2 kΩ)}$
- R7 $\text{(1 kΩ)}$
- R8 $\text{(10 kΩ)}$
LEDs:
- LED1
- LED2
Diode: D1
Battery: [BT1](ML414H IV01E) $\text{(ML414H IV01E)}$
Connectors:
- [J1](JST Sales America Inc.)
- J2
- J3 $\text{(TYPE-C-31-M-12)}$
- J4 $\text{(FTSH-105-01-L-DV-007-K)}$

If you need more information about any specific part, feel free to ask!

Someone is typing...

please explain what L1 does.

nimaflux

@copilot please explain what L1 does.

copilot

In your circuit,

L1

is an inductor with an inductance of 22 µH. Inductors are passive components that store energy in a magnetic field when an electric current flows through them. They are commonly used in various applications, such as filtering, energy storage, and impedance matching.

In your project,

L1

is likely being used for filtering purposes. Based on your project description, it seems connected to the RF input of the NEO-6M-GPS module. This could mean it is being used as part of an RF matching network to filter out unwanted signals and ensure that only the desired frequency components are allowed to pass to the GPS module.

If you have more specific questions about its function or need further assistance with it in the context of your design, feel free to ask!

Someone is typing...

VUSB

STM_RST

SWCLK

VBAT

3V3

SIM_TX

SWDIO

VBAT

Resistance

5KΩ

Resistance

5KΩ

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Project Name

Pet Tracker Device

Description

This is a Pet Tracker Reference Design based on STM32L4. Tracker connects with network by SIM800L module connected to the STM. Also MCU connected to the GPS by uart and send data to server #STM32 #GPS #G4 #G3 #LTE #IoT #Tracker #smartHomeDevices #referenceDesign #edge-computing #edgeComputing #stm #template #referenceDesign

Properties

License

creativecommons.org/licenses/by/4.0/

Pricing & Availability

Distributor	Qty 1
Digi-Key	$8.52–$9.78
LCSC	$13.91
Mouser	$8.23

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vasyl / Pet Tracker Device

Schematic