BM3451 startup level lithium battery protection board

BOM download

PCB_PCB_BM3451 startup level lithium battery protection board_2022-09-23.pdf

PCB_PCB_BM3451 startup level lithium battery protection board_2022-09-23.json

PCB_BM3451 startup level lithium battery protection board_2022-09-23.pcbdoc

Gerber_PCB_BM3451 startup level lithium battery protection board.zip

Schematic_BM3451 startup level lithium battery protection board_2022-09-23.pdf

SCH_BM3451 startup level lithium battery protection board_2022-09-23.json

Sheet_1_2022-09-23.schdoc

61635

SI4825 DSP mechanically tuned digital radio

Introduction: High-sensitivity AM SW FM radio with simple circuit and easy installation. Very suitable for DIY.

Mechanical Tuned AM/FM/SW Radio Receiver
Features
Application
Description
The Si4825 is an entry-level mechanically tuned digital CMOS AM/FM/SW radio receiver IC that integrates
all receiving functions from antenna input to audio output. The Si4825 expands Silicon Labs' family of multiband tuners
that
further . During production, the Si4825 requires

a simple application circuit and eliminates the need for all manual tuning components during production. This receiver consumes very little
power and operates on two AAA batteries, providing the analog radio market with the performance advantages of digital tuning.
Functional block diagram
 Supports global FM band
(64–109 MHz)
 Supports global AM band
(504–1750 kHz)
 Supports shortwave band
(2.3–28.5 MHz)
 No manual calibration required
 Mono audio output
 AM/FM/SW Regional band optional
∎ Enhanced FM/SW band coverage
∎ Automatic frequency control (AFC)
∎ Integrated LDO regulator
∎ 2.0 to 3.6 V supply voltage
∎ Supports wide-band ferrite rod antenna and air
loop antenna
∎ 16 Pin SOIC
 RoHS compliant
 Direct volume control
 Not EN55020 compliant*
*Note: For
consumer , use the Si483x.
∎ Desktop and Portable Radios
∎ Micro/Small Systems
∎ CD/DVD Players
∎ Speakers
∎ Modules
∎ Timer Radios
∎ Mini HiFi
∎ Entertainment Systems

 
 

si4825-a10-datasheet-cn.pdf

Si4825DEMO.pdf

59fc9b23d4b31afda6d7cc637f8de033.mp4

BOM download

PCB_PCB_SI4825 Radio_2022-09-23.pdf

PCB_PCB_SI4825 Radio_2022-09-23.json

Schematic_SI4825 DSP mechanically tuned digital radio_2022-09-23.pdf

SCH_SI4825 DSP mechanical tuning digital radio_2022-09-23.json

Sheet_1_2022-09-23.schdoc

61636

si4844 mechanically tuned digital display full band radio

Introduction: stm32F103C8T6 Arduino For ARM si4844 mechanically tuned digital display full-band radio with super good sensitivity. The shortwave and FM antennas are only 37CM ​​and have basically the same effect as the Tecsun PL600.

   Using ST7565LCD liquid crystal display (screen of a certain Baoan Xinjia). There is no backlight, so a 4020RGB backlight is added to display the colorful backlight. Added DS3231 high-precision clock and DS18B20 temperature display. There is also a Bluetooth TFT card player designed by JL Jerry. Because the buttons are connected in parallel with the radio, there is a conflict. This function does not need to be used. Time setting: Press BASS- VoL- at the same time to enter the setting menu BASS+ year setting 18-60 years can only be increased upwards. The BAND+ month setting also increases by 1-12, the vol+ day setting also increases by 1-31, the bass-hour setting also increases by 0-24, the BAND-minute setting also increases by 0-59, and the VOL-second setting also increases by 0- 59. After setting, press the RGB LED key to save the settings, so that the settings can be accurate to the second. Press SET key to exit setting. I’ll talk about other functions when I have time. Due to PCB space limitations, the AM antenna is too close to the CPU to cause high interference. Improvements will be made in the future (adjusting component locations or adding shielding covers).
   Attached are two boards with PCB proof files. As well as SI4844B20 Chinese manual and official PCB design specification DEMO.
   Program compilation instructions: To build the Arfuino For STM platform, you need to first download the MAPLE firmware for STM32F103C8T6 to support Arduino software. Specifically Baidu. The attachment comes with an Arduino program. Libraries used: Please download in the Arduino software. PU2CLRSI4844, U8G2, DS3231. The program is a bit messy, just a novice.