2 layers95 × 65 mm
2 layers41.9 × 55.6 mm
Trace Talk
Sadrita404/Trace-TalkTraceTalk is a Walkie talkie radio pin badge with a custom PCB and an ATMEGA328P (Arduino) microcontroller. Integrated rechargable battery, can be charged using any USB-C cable and USB power supply.
- Size
- 41.9 × 55.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 44
- Nets
- 54
- Pads
- 175
- Tracks, vias
- 261, 36
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 29 Jun 2026
- Updated
- 20 Jul 2026
Overview
Trace Talk is an open-source printed circuit board by Sadrita404, from the Sadrita404/Trace-Talk repository on GitHub, published under the MIT licence. It is a 2-layer board of 41.9 × 55.6 mm with 44 parts on 54 nets, routed with 261 tracks and 36 vias.
It is built around the ATMEGA328P-AU, LM358 and MIC5205-3.3YM5, with the TP4056 among its other parts. Its parts include 13 resistors, 11 capacitors, 5 ICs, 2 diodes and 2 connectors. It belongs with the power and radio and wireless boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
4
ATMEGA328P-AU
TQFP-32(7x7)-40℃~+85℃ 1.8V~5.5V 10bit 1KB 20MHz 23 2KB 32KB 8 Bit AVR Built-in FLASH TQFP-32(7x7) Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
LM358
SOP-8-18V~18V 0℃~+70℃ 1.2MHz 10nA 2 24mA 3V~36V 500uA 50nA 5mV 80dB Built-in compensation SOP-8 Operational Amplifier ROHSMSKSEMIOperational Amplifier
MIC5205-3.3YM5
SOT-23-5-40℃~+85℃@(Ta) 1 150mA 200mV@(50mA) 20V 2uA 3.3V 70dB@(1kHz) Fixed Over Current Protection、Over Temperature Protection Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTECH PUBLICVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
TP4056
ESOP-8-40℃~+85℃ 1 1A 35uA 4.2V 4V~6.5V Charging IC Lithium Battery Support Support 恒流充电、恒压充电、涓流充电、自动再充电、充电终止、可编程充电电流、软启动、欠压锁定 ESOP-8 Battery Management ROHSUMWBattery Management
README
README.md|
|
| Title | Trace Talk |
|---|---|
| Author | Sadrita Neogi |
What's this?
TraceTalk is a walkie-talkie small radio powered by a custom PCB and an ATMEGA328P (Arduino) microcontroller. It features a built-in rechargeable battery that charges with any standard USB-C cable and power brick. I also put together a custom enclosure to keep the PCB safe.
Why I built it ?
From a very starting point, I walkie talkie due to their principle of work like the transmission between two devices without any internet connection and we are able to talk to each other. This made me fascinated, and I also wanted to make one for myself, but in general, the walkie-talkie that we see is balki and heavy so I made it pocket size, slim, walkie-talkie that can be connected via headphone and we can use it.
How to use ?
To use the walkie-talkie, just plug any headphones with a mic into the 3.5mm jack, then flip the switch on the left side of the board and the LED will turn on. Just press and hold the button on the board to transmit your voice, and any nearby walkie-talkies will pick it up and play the audio. No pairing or setup needed.
The battery will lasts for about 4 hours( according to my calculation that I have made by going to the data sheet of each components, and this is what I approximately estimated ) and charges with any USB-C cable and power source. While it's charging, an LED near the USB port will light up, and it'll turn off once the battery is fully charged. Just a heads-up: the headphones you use can affect the audio quality, so you might want to try a few different pairs to see what works best.
Technical Description
This project runs on an ATMEGA328P microcontroller sitting on a custom PCB (TraceTalk). It sends all the audio data through an NRF24L01 radio module. The ATMEGA328P runs at 3.3V and 8MHz, and you can program it right through the Arduino IDE. While you could technically use an external programmer like a USBTinyISP, the Arduino IDE is definitely the easiest and most straightforward way to go.
For the radio, I used the SMD version of the NRF24L01 to keep the board as small as possible. It gets a maximum range of about 100 meters.
The LiPo battery is soldered straight onto the board's battery terminals. I’d recommend picking up a battery with a 100-150mAh capacity—that’s the sweet spot for getting the best results.
| Building Process | ||
|---|---|---|
Final Look
|
▲ Front Side View
|
▲ Back Side View
|
Bill of Materials
| Name | Purpose | Qty | Total (USD) | Link | Distributor |
|---|---|---|---|---|---|
| PCBA SMT Assembly | SMT assembly of all SMD components | 5 | 51.93 | — | JLCPCB |
| PCB Fabrication (Trace Talk) | 2-layer PCB — the board itself | 5 | 2.00 | — | JLCPCB |
| C10,C11,C3 | 100nF 50V X7R ±10% 0805 MLCC | 25 | 0.87 | Link | JLCPCB |
| D1,D2 | Red Water Clear 0805 LED Indication | 22 | 0.31 | Link | JLCPCB |
| J1 | 1A 3.5mm Headphone Jack 30V SMD R/A | 6 | 0.63 | Link | JLCPCB |
| J2 | 0.3mm 1mm 5P Right Angle Top Contact FFC/FPC Connector | 6 | 0.59 | Link | JLCPCB |
| R1,R5,R6 | 330Ω 125mW 150V Thick Film Resistor ±5% 0805 | 25 | 0.07 | Link | JLCPCB |
| R2,R3 | 5.1kΩ 125mW 150V Thick Film Resistor ±1% 0805 | 10 | 0.04 | Link | JLCPCB |
| R10,R4 | 1kΩ 125mW 150V Thick Film Resistor ±1% 0805 | 20 | 0.09 | Link | JLCPCB |
| R11,R12,R13,R7,R8,R9 | 10kΩ 125mW 150V Thick Film Resistor ±1% 0805 | 30 | 0.13 | Link | JLCPCB |
| C1,C2,C4,C5,C6,C8 | 10V 10uF X5R ±10% 0805 MLCC | 40 | 7.11 | Link | JLCPCB |
| SW1 | PCM12SMTR SPDT Surface Mount Vertical Slide Switch | 5 | 6.23 | Link | JLCPCB |
| SW2 | PTS645 Tactile Switches 12V 50mA SMD-4P 6x6mm | 5 | 1.53 | Link | JLCPCB |
| U2 | MIC5205-3.3YM5-TR Fixed 3.3V 150mA Linear LDO SOT-23-5 | 5 | 1.88 | Link | JLCPCB |
| U3 | TP4056X-42-ESOP8 1A 4.2V Lithium Battery Charging IC | 5 | 1.00 | Link | JLCPCB |
| U4 | LM358DR2G 32V Dual Operational Amplifier SOIC-8 | 5 | 0.29 | Link | JLCPCB |
| U5 | ATMEGA328P-AU 8-Bit AVR 20MHz TQFP-32 Microcontroller | 5 | 11.38 | Link | JLCPCB |
| USB1 | USB Type-C Receptacle 16P Female SMD R/A | 5 | 0.92 | Link | JLCPCB |
| X1 | 8MHz 33pF SMD3213-3P Ceramic Resonator | 5 | 1.92 | Link | JLCPCB |
| RG1 | 470kΩ 125mW 150V Thick Film Resistor ±1% 0805 | 5 | 0.02 | Link | JLCPCB |
| C7,C9 | 330nF 50V X7R ±10% 0805 MLCC | 20 | 0.66 | Link | JLCPCB |
| 3.7V 100mAH | To power the circuit | 2 | 0.00 | Link | Self Sourced |
| 3d Print | For the encloser | 1 | 0.00 | Link | #printing-legion |
| Shipping PCB | E- Post (Cheapest) | - | $10.98 | — | JLCPCB |
| Total | $100.58 |
Project Under Hack Club
Parts
44| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 10k | Resistor_SMD:R_0805_2012Metric | R7, R8, R9, R11, R12, R13 |
| 6 | 10uF | Capacitor_SMD:C_0805_2012Metric | C1, C2, C4, C5, C6, C8 |
| 3 | 100nF | Capacitor_SMD:C_0805_2012Metric | C3, C10, C11 |
| 3 | 330 | Resistor_SMD:R_0805_2012Metric | R1, R5, R6 |
| 3 | LOGO | LOGO | G***, G***, G*** |
| 2 | 1k | Resistor_SMD:R_0805_2012Metric | R4, R10 |
| 2 | 330nF | Capacitor_SMD:C_0805_2012Metric | C7, C9 |
| 2 | 5.1k | Resistor_SMD:R_0805_2012Metric | R2, R3 |
| 2 | LED_0805 | LED_SMD:LED_0805_2012Metric | D1, D2 |
| 1 | 470k | Resistor_SMD:R_0805_2012Metric | RG1 |
| 1 | ATmega328P-A | Package_QFP:TQFP-32_7x7mm_P0.8mm | U5 |
| 1 | ICSP | Connector_FFC-FPC:Molex_200528-0050_1x05-1MP_P1.00mm_Horizontal | J2 |
| 1 | Jack 3.5mm | Connector_Audio:Jack_3.5mm_PJ320D_Horizontal | J1 |
| 1 | LM358 | Package_SO:SOP-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | LiPo 100mAh | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | BT1 |
| 1 | MIC5205-3.3YM5 | Package_TO_SOT_SMD:SOT-23-5 | U2 |
| 1 | NRF24L01_Breakout | Custom footprints:NRF24L01_Mini | U1 |
| 1 | Pushbutton | Button_Switch_SMD:SW_SPST_PTS645 | SW2 |
| 1 | Resonator 8MHz | Crystal:Resonator_SMD_Murata_CSTxExxV-3Pin_3.0x1.1mm | X1 |
| 1 | SPDT_PCM12 | Button_Switch_SMD:SW_SPDT_PCM12 | SW1 |
| 1 | TP4056 | Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm | U3 |
| 1 | USB_C 31-M-12 | Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12 | USB1 |
The 42 most common of 44 parts.
Questions
How big is the Trace Talk PCB?
It measures 41.9 × 55.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Trace Talk use?
44 parts, built around the ATMEGA328P-AU, LM358, MIC5205-3.3YM5 and TP4056. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Trace Talk KiCad files?
From the Sadrita404/Trace-Talk repository on GitHub, at the commit this page was made from: the board is PCB/TraceTalk.kicad_pcb and its schematic PCB/TraceTalk.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Trace Talk design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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