Today I introduce to you an FM radio module with which I actually wanted to play with its serial interface. This did not work (in my case), and so the receiver module still has its home in a cardboard box.
If you want to take 24 minutes for a video, I recommend this link.
Here the approximately 8 Euro candidate: in addition you need either your earphone output (3.5 "jack) or in my case 2 speakers, max 4 ohms, 3 watts. Do you plug in an earphone, so that has priority over the speakers.
The module has no on / off switch, so thinks of a switch. The small display (2.6 x 1.9 cm) shows the frequencies sufficiently large.
When buying, pay attention to the version of the module: different modules are offered in different shops.
The 2x M8 hexagon nuts I tightened hand-tight, after I had previously solved with a knife and ruler the necessary speaker and display sections. With the soldering iron I stowed the components inside the box.
In my case, the control of TX / RX should not be. Hope you have more success if necessary. Serial commands here. It would be great to be able to handle the frequency selection via the browser or via the mobile phone.
Datasheets and help with the serial commands can be found below the video from above. Here folds the tab below the video description and follows to Dropbox filing.
At icstation you will find more housing-ideas.
You can search for radio stations and store radio function.
As far as a nice bad weather project. In the further course still product details and operating tips.
Product parameters- Output power: 500 mW (drive headphones), 3W x 2 (driving the speaker)
- Frequency range: 50Hz-18KHz
- Receiving frequency range:
- Close the campus radio 87.0MHz-108.0MHz,
- Open campus radio 76.0MHz-108.0MHz
- Equivalent noise: =30dB
- Supply voltage: 3.0V-5.5V
1. Power
The corresponding module port (PCB board labeling) -, +, respectively, then the power supply (battery) negative electrode and a positive electrode, a battery or other power source is recommended power supply. You can not use switching power supply without a filter (such as mobile phone chargers, and other switching power supply), or interfere with the power generated will affect the normal operation of the module. This module normal operating voltage of 3.0-5.5V, be careful not to exceed the supply voltage range.
2. Antenna
FM_ANT port used to connect FM antenna for better reception FM signal, they recommend an external 75 cm length of the rod antenna.
3. headphone / speaker output
The module comes with 3 Watt x 2 channel audio amplifier, speakers to access the speaker ports is recommended 4 Ohm / 3 Watt speakers. Such as plug in your headphones, audio is automatically switched to the headset channel speaker channels automatically shut down.
4. Volume control
Turn the VOL encoder to adjust the volume, while the LCD screen shows the volume series.
5. frequency regulation
FRE rotation encoder, receiving frequency, while the LCD screen displays the current frequency down short, encoder handle press to mute / un-mute switch.
6. Mute
Press VOL knob down mute / un-mute
7. Auto mute switch
Press down FRE knob turned on or off automatic mute function, LCD display captions ON Enables automatic squelch, OFF means turn off the automatic squelch.
8. Automatic squelch threshold (Threshold) Adjustment (automatic mute switch opens effective)
Press FRE knob down, into the automatic squelch threshold adjustment interface, the user can use specific actions to adjust the automatic squelch threshold, adjustment range is 0-20, the higher the value, the more limited the door, the more likely weak signal Mute. On the contrary the opposite.
9. access the serial port (not serial control without contact)
TTL level serial port module reserve control interface, TTL serial communication module of the need to connect UART_RX, UART_TX and GND Module (PCB corresponding to the location, there is marked), you can use an external MCU (microcontroller) or PC serial port to send commands associated control module Features.
Note: Due to computer serial port level is not a TTL level, when connected to a computer connected to RS323 communication required to TTL level electrical switching device paperback or use USB to TTL level serial port module to communicate with the module. Because serial command control module requires some computer expertise, but not buyers please do not try.
Termite Download for PC: https://www.compuphase.com/software_termite.htm
10. User Set
This module can be set whether the backlight state to listen to campus radio band, set as follows according to the user's application. Power-off state long press the VOL knob down electrical power LCD display showing open campus radio C0 C1 represents closed campus radio band, set to take effect after the restart. By setting the backlight state is off state press FRE knob key to turn the display backlight. Always indicate B1, B0 denotes a backlight turned off 20 seconds after the restart to take effect. Repeat this step to change the setting to switch the state. The factory is set to not open unified campus radio band, backlight turns off 20 seconds without operation.
Note: The factory default setting is Off campus radio, the backlight automatically turns off no operating 20S, Off Auto Squelch. Users set their own depending on the circumstances.
This module squelch adjustment method:
This module uses DSP digital squelch, the flexibility to use software to control the squelch threshold (threshold). When squelch threshold is 0-20 levels, the lower the number the lower the squelch threshold, the more likely to listen to the radio signal with the background noise, the higher the number, the higher the noise threshold, the output noise is higher than the set value, the automatic static Noise open, so that the output is muted. So when adjusting the squelch threshold, according to the case, if you want to hear the weak signal squelch threshold go down, if you want to hear a strong signal, number to increase.
Note that the mute function is not the signal to remove background noise, but the noise level is determined by the signal exceeds the threshold value to control the output muted.
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