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EJA M v1.0 - Bill of Materials

A project log for 2021 HDP Dream Team: EJA

Learn more about Team EJA's intelligent buoy, and how their solution will help the global fight against ghost gear.

Leonardo WardLeonardo Ward 09/24/2021 at 15:510 Comments

This log presents the bill of materials of our new PCB EJA M v1.0. This new PCB will replace our intelligent buoy (Buoy A v1.0 and Buoy B v1.0), and our Onboard Gateway v1.0.

Full Version

To create an intelligent buoy we need to solder the complete PCB EJA M v1.0. The following table contains all the components and their current price (obtained at the moment of writing this log, it might change in the future).

PCB Components

NameQuantityPrice
PCB1$0.50 
47 µF ±20% 6.3V Ceramic Capacitor 08051$0.35
10 µF ±10% 6.3V Ceramic Capacitor 08054$0.12
12 pF ±5% 50V Ceramic Capacitor 08051$0.10
680 pF ±10% 25V Ceramic Capacitor 08051$0.10
47 pF ±5% 16V Ceramic Capacitor 08053$0.10
100 µF ±20% 6.3V Ceramic Capacitor 12101$0.96
0.1 µF ±10% 50V Ceramic Capacitor 08053$0.10
4.7 uF ±10% 6.3V Ceramic Capacitor 08051$0.12
1 µF ±10% 16V Ceramic Capacitor 08054$0.16
2.2 µF ±10% 10V Ceramic Capacitor 08051$0.12
220 µF Tantalum Capacitors 10V 29171$0.99
0.033 µF ±10% 50V Ceramic Capacitor 08051$0.10
Orange 601nm LED - Discrete 2.1V 08051$0.30
Green 520nm LED - Discrete 3.2V 08052$0.18
TVS Diode 15V Clamp 5A (8/20µs) SOT-23-61$0.49
Red 630nm LED - Discrete 1.9V 08051$0.18
Yellow 590nm LED - Discrete 2V 08051$0.29
1 Signal Line Ferrite Bead 0805 300mA 350mOhm2$0.11
USB-C USB 3.2 Gen 2 Receptacle Connector1$2.44
Battery Retainer Coin, 20.0mm 1 Cell PC Pin1$0.29
U.FL (UMCC) Connector Receptacle2$1.22
Battery Holder (Open) 18650 1 Cell PC Pin1$4.17
2 Position Terminal Block Horizontal1$0.84
2.2 µH Inductor 15 A 7mOhm Max1$0.95
5.5 µH Inductor 10 A 10.3mOhm1$4.15
Bipolar (BJT) Transistor NPN 30V 600mA SOT-23-33$0.18
1 MOhms ±1% 0.125W Chip Resistor 08052$0.10
90.9 kOhms ±1% 0.125W Chip Resistor 08051$0.10
620 Ohms ±5% 0.125W Chip Resistor 08055$0.10
5.1 KOhms ±1% 0.125W Chip Resistor 08053$0.10
49.9 KOhms ±1% 0.125W Chip Resistor 08051$0.10
825 kOhms ±0.5% 0.125W Chip Resistor 08051$0.11
182 kOhms ±1% 0.25W Chip Resistor 08051$0.10
1.2 kOhms ±5% 0.125W Chip Resistor 08051$0.10
6.49 kOhms ±1% 0.125W Chip Resistor 08051$0.10
27 Ohms ±1% 0.125W Chip Resistor 08052$0.10
10 kOhms ±1% 0.125W Chip Resistor 080510$0.10
1 kOhms ±1% 0.125W Chip Resistor 08051$0.10
1.8 MOhms ±1% 0.125W Chip Resistor 08051$0.10
390 kOhms ±1% 0.125W Chip Resistor 08051$0.10
806 kOhms ±1% 0.125W Chip Resistor 08051$0.10
2 MOhms ±1% 0.125W Chip Resistor 08051$0.10
180 kOhms ±0.5% 0.1W Chip Resistor 08051$0.10
0 Ohms Jumper 0.125W Chip Resistor 08052$0.10
ATGM332D-5N31 GNSS Series GPS+BDS 12.2x16x2.4mm1$5.81
Buck-Boost Switching Regulator 1.8V 1 Output 3A1$10.09
TP4056 ESOP-8 Battery Management1$0.1595
ESP32-WROOM-32D (4MB)1$4.08
FTDI USB Bridge, USB to I²C/UART USB 2.0 I²C, UART Interface 28-TSSOP1$1.99
TPS61030PWPR Boost Switching Regulator IC Positive Adjustable 1.8V 1 Output 3.6A (Switch)1$3.13
RFM95W-915S2-ND LoRa Transceiver Module 915MHz1$13.44
DS3231M+TRL Real Time Clock I²C, 2-Wire Serial1$8.23
Power Supply On/Off Controller Push Button1$5.76
Connector Header Through Hole 40 position (2.54mm)1$0.57

External Components

NameQuantityPrice
SERVOMOTOR RC 5V HIGH TORQUE1$9.95 
CR2032 Lithium Coin Cell Battery1$0.95
18650 Lithium-Ion 3.7V Battery Rechargeable 3.4Ah1$11.99
ADXL343 - Triple-Axis Accelerometer1$5.95

The overall price of the full PCB is $108.39.

Comparing the price to our previous PCB designs we have:

DesignBuoy A v1.0Buoy B v1.0EJA M v1.0 (Full)
Features- ESP32
- LoRa
- GPS
- Servo Motor
- Real Time Clock
- DC Motor
- 4G (LTE)
- ESP32
- LoRa
- GPS
- Servo Motor
- Real Time Clock
- DC Motor
- ESP32
- LoRa
- GPS
- Servo Motor
- Real Time Clock
- Battery Charger
- Battery Level Indicator
- Accelerometer
Price$201.01$131.02$108.39

Reduced Version

To create an Onboard Gateway we can use the PCB EJA M v1.0 with less components than the full version. The following table contains the required components and their current price (obtained at the moment of writing this log, it might change in the future).

PCB Components

NameQuantityPrice
PCB1$0.50 
47 µF ±20% 6.3V Ceramic Capacitor 08051$0.35
10 µF ±10% 6.3V Ceramic Capacitor 08053$0.12
12 pF ±5% 50V Ceramic Capacitor 08051$0.10
680 pF ±10% 25V Ceramic Capacitor 08051$0.10
47 pF ±5% 16V Ceramic Capacitor 08053$0.10
100 µF ±20% 6.3V Ceramic Capacitor 12101$0.96
0.1 µF ±10% 50V Ceramic Capacitor 08052$0.10
4.7 uF ±10% 6.3V Ceramic Capacitor 08051$0.12
1 µF ±10% 16V Ceramic Capacitor 08054$0.16
0.033 µF ±10% 50V Ceramic Capacitor 08051$0.10
Orange 601nm LED - Discrete 2.1V 08051$0.30
Green 520nm LED - Discrete 3.2V 08052$0.18
TVS Diode 15V Clamp 5A (8/20µs) SOT-23-61$0.49
Red 630nm LED - Discrete 1.9V 08051$0.18
Yellow 590nm LED - Discrete 2V 08051$0.29
1 Signal Line Ferrite Bead 0805 300mA 350mOhm2$0.11
USB-C USB 3.2 Gen 2 Receptacle Connector1$2.44
Battery Retainer Coin, 20.0mm 1 Cell PC Pin1$0.29
U.FL (UMCC) Connector Receptacle1$1.22
Battery Holder (Open) 18650 1 Cell PC Pin1$4.17
2 Position Terminal Block Horizontal1$0.84
2.2 µH Inductor 15 A 7mOhm Max1$0.95
Bipolar (BJT) Transistor NPN 30V 600mA SOT-23-32$0.18
1 MOhms ±1% 0.125W Chip Resistor 08051$0.10
90.9 kOhms ±1% 0.125W Chip Resistor 08051$0.10
620 Ohms ±5% 0.125W Chip Resistor 08055$0.10
5.1 KOhms ±1% 0.125W Chip Resistor 08053$0.10
49.9 KOhms ±1% 0.125W Chip Resistor 08051$0.10
825 kOhms ±0.5% 0.125W Chip Resistor 08051$0.11
182 kOhms ±1% 0.25W Chip Resistor 08051$0.10
1.2 kOhms ±5% 0.125W Chip Resistor 08051$0.10
6.49 kOhms ±1% 0.125W Chip Resistor 08051$0.10
27 Ohms ±1% 0.125W Chip Resistor 08052$0.10
10 kOhms ±1% 0.125W Chip Resistor 08059$0.10
806 kOhms ±1% 0.125W Chip Resistor 08051$0.10
2 MOhms ±1% 0.125W Chip Resistor 08051$0.10
0 Ohms Jumper 0.125W Chip Resistor 08052$0.10
Buck-Boost Switching Regulator 1.8V 1 Output 3A1$10.09
TP4056 ESOP-8 Battery Management1$0.1595
ESP32-WROOM-32D (4MB)1$4.08
FTDI USB Bridge, USB to I²C/UART USB 2.0 I²C, UART Interface 28-TSSOP1$1.99
RFM95W-915S2-ND LoRa Transceiver Module 915MHz1$13.44
DS3231M+TRL Real Time Clock I²C, 2-Wire Serial1$8.23
Power Supply On/Off Controller Push Button1$5.76
Connector Header Through Hole 40 position (2.54mm)1$0.57

External Components

NameQuantityPrice
CR2032 Lithium Coin Cell Battery1$0.95
18650 Lithium-Ion 3.7V Battery Rechargeable 3.4Ah1$11.99

The overall price of the full PCB is $76.07.

Comparing the price to our previous PCB design we have:

DesignOnboard Gateway v1.0EJA M v1.0 (Reduced)
Features- ESP32
- LoRa
- Battery Charger
- ESP32
- LoRa
- Battery Charger
- Real Time Clock
- Battery Level Indicator
Price$84.34$76.07

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