Picaxe AXE171 User manual

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AXE171 PICAXE-14 Audio Kit © Revolution Education Ltd 2015 v1.1 May be copied for educational use. 1
AXE171 PICAXE-14 Audio Kit
The AXE171 is a small PICAXE-14M2 project designed to connect to the SPE035 MP3 player module.
Both kits are provided within the PICAXE-14 Audio kit.
The SPE035 Serial MP3 player consists of a small MP3 player module mounted on a PCB with serial
connector, test switches and 8 ohm speaker. It provides a simple and low cost way to add MP3 tune
playback to any PICAXE project.
The MP3 audio files (music, speech etc.) are copied onto a microSD card (not included) which is then
inserted into the MP3 player. A simple 3 wire connection to the PICAXE project then allows playback
and control of the audio tunes.
AXE171 Features：
1. PICAXE-14M2 Microcontroller
2. Two LED outputs and two spare outputs e.g. for Serial LCD or Servo
3. Push switch and LDR light sensor
4. MP3 player interface
SPE035 Features：
1. Supports MP3 files with all most common file sampling frequencies (kHz):
i. 8 / 11.025 / 12 / 16 / 22.05 / 24 / 32 / 44.1 / 48
2. High quality playback on 8 ohm speaker (included) with 90dB dynamic range
3. PCB pads for alternate stereo line out audio connection
4. Supported file format: MP3 / WAV
5. Supports 1GB to 32GB microSD card (FAT16 or FAT32)
6. 30 volume settings (1= mute, 30 = full volume)
7. 6 equalizer settings (0=Normal, 1=Pop, 2=Rock, 3=Jazz, 4=Classic, 5=Bass)
8. TTL serial control playback mode, at 9600 baud rate (PICAXE serout at T9600_8)
9. Power supply can be 3.3 to 5.2V DC
10. On board switches for playback testing
For the full datasheet see www.picaxe.com/docs/axe171.pdf

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1.1 AXE171 Kit Contents
1 PCB AXE171 pcb
1 SW1 SEN030 6mm push switch
2 R1,6 RES-330 330 resistor (orange orange brown gold)
3 R2,3,5 RES-10K 10k resistor (brown black orange gold)
1 R4 RES-22K 22k resistor (red red orange gold)
1 C1 CAP001 100nF capacitor
1 IC1 ICH014 14 pin IC socket
1 IC1 AXE017M2 PICAXE-14M2 (pin 1 placed next to C1)
1 LDR SEN002 LDR
2 L1-2 LED001 5mm red LED (long leg +)
1 H1 CON043 5 pin r/a socket
1 CON1 CON039 3.5mm download socket
1 CON2 BAT016 4.5V battery clip

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1.2 AXE171 Assembly
Note –Before assembly decide whether you may prefer to solder the LEDs, LDR, switch (and also the
SPE035 speaker) on the reverse side of the PCB (therefore soldering these component pins on the top
side of the board). This is often useful when mounting the PCB through a cardboard model. The PCB
supplied is a high quality plated through PCB with solder pads on both sides.
1. Solder the resistors in position R1-R6 and the capacitor in position C1.
2. Solder the switch in position SW1
3. Solder the 5 pin right angle socket (H1) and the 3.5mm download socket (CON1) in position.
Make sure this download socket ’snaps’ flat on the PCB.
4. Solder the 14 pin IC socket in position, noting the pin 1 notch is to the bottom of the board.
5. Solder the LEDs and LDR to the board. You may wish to leave these with long legs or to
solder them on the reverse of the PCB. Make sure the LEDs are correctly aligned with the
marking on the PCB, long leg through the hole marked +.
6. Solder the battery clip to the board. You may choose to thread the two wires through the
large hole first to make a more durable connection (see photo above). Make sure the red
(RED) and black (BLK) wires are the correct way around.
Insert the PICAXE-14M2 into the socket. Note that pin 1 (notched end of chip) is placed next to the
capacitor at the bottom of the PCB so that the chip is ‘upside down’ (see photo above).
The board is designed to be used with a 4.5V (3xAA) battery pack. Do NOT use a 9V PP3 battery.
The additional holes and pads on the PCB are not required at this stage and so can be ignored.

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2.0 SPE035 Kit Contents
1 PCB SPE035 pcb
3 SW1-3 SEN030 6mm push switch
1 R1 RES-1K 1k resistor (brown black red gold)
1 C1 CAP001 100nF capacitor
1 H1 CON042 5 pin r/a header
1 SPK1 SPE015 8 ohm PCB mount speaker
2 MP3 socket CON050 8 way 2.54mm sockets (optional)
1 MP3 player SPE033 DFPlayer Mini (or similar clone)

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2.1 SPE035 Assembly
Solder the 1k resistor in position R1 and capacitor in position C1.
Solder the three switches in positions SW1 to SW3
Solder the MP3 module in the appropriate position A or B (see note 1.1 above). The module
may be soldered directly onto the board or the optional 8 way connectors supplied may be
used (if you wish to be able to remove the module from the PCB in the future).
On the 5 way connector carefully push hard on the corner of the first pin (e.g. with a coin) so
that the short end slides through the plastic holder, therefore making the short end longer.
Do this for all 5 pins. Place the longer end through the PCB in position H1 and solder in
position. The connector is adjusted and used like this so it lies closer to the top of the PCB.
Solder the speaker wires into positions SPK1 and SPK2. There are 3 different solder pad
positions to allow for different speaker sizes and shapes. If you wish to use a different size of
speaker it should be an ‘8 ohm’ type. The speaker can be connected either way round.

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3.0 Loading MP3 files onto your micro SD card (not included)
IMPORTANT –Note the microSD card socket on the top of the MP3 module is a ‘push to eject’ style
socket (so you must press the card inwards slightly to eject it). If you simply pull hard on the card
without ejecting it you may cause physical damage to the socket and/or module!
MP3 music/speech files may be copied onto the card using a mobile phone, tablet or computer (a
separate SD card adapter may be required to insert the microSD card into a computer). MicroSD
cards from 1GB to 32GB are supported. Many people may already have a surplus micro SD card from
an old mobile phone which will be ideal.
The music filenames must have filenames starting with 0001.mp3, 0002.mp3, 0003.mp3 etc. and be
saved in a subfolder called \MP3 on the microSD card.
A set of sample MP3 files for testing may be downloaded from
www.picaxe.com/downloads/mp3.zip
So the MP3/WAV files copied onto the microSD card should:
Use a filename that starts with 4 numeric characters e.g. 0001.mp3, 0002.wav
Use a filename that starts with numbers between 0001.mp3 and 0255.mp3
End with .mp3 or .wav
Be saved within a folder called \MP3 on the microSD card
Be unprotected files - DRM ‘copyright protected’ music files are not supported
Once the music and speech files have been copied onto the micro SD card carefully and gently insert
the card into the socket on the MP3 module.

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3.1 Step by step guide to copying MP3 files on to the SD card:
If using an old recycled microSD card it is best to ‘Quick Format’ it before use.
Step 1.
Insert the microSD card into
the computer (an adapter
may be required), right click
over the microSD card drive
and select ‘Format…’
Step 2.
Make sure ‘Quick Format’ Is
selected.
Double check that it is
definitely the microSD card
drive that is selected (as
formatting permanently
deletes all data)
Click Start
Step 3.
Once formatting is complete
create a new folder called
MP3 on the microSD card
Step 4.
Copy the MP3 files into the
\MP3 sub folder. It is best to
copy the files one at a time
in order (see notes in 2.0)

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3.2 Testing the MP3 files (using the on-board switches).
1. Make sure the microSD card containing MP3 files has been inserted into the MP3 player.
2. Connect power (4.5V battery box) to the AXE171 battery clip.
3. Press the left play (>) switch, the first tune found will then play.
4. A short press of the centre (>> / +) switch will move to the next track.
5. A short press of the right (<< / -) switch will move to the previous track.
6. A long press of the centre (>> / +) switch will increase the volume.
7. A long press of the right (<< / -) switch will decrease the volume.
Note that, as with most MP3 players, the next/previous track push buttons operate on the FAT file
system sort, not the alphabetical filename sort. So the next/previous track played will be according to
the order that the files were originally saved onto the card, not via an alphabetical sort of the
filenames currently on the card. Use a search engine search as Google to find a ‘FAT filename sorter’
utility program if the push switch playback order is essential and must be amended.
When playback is controlled by serial commands from a PICAXE chip the files are called directly by
filename number, so the sort order on the microSD card is then not important.

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4.0 Example PICAXE programs
PICAXE-14M2 Input / Output Connections
B.0 Programming
B.1 Spare - Serial LCD or Servo (optional)
B.2 Top LED
B.3 Spare - Serial LCD or Servo (optional)
B.4 TX to MP3 player
B.5 Bottom LED
C.0 Push switch
C.1 Spare
C.2 BUSY from MP3 player
C.3 RX from MP3 player
C.4 LDR
Examples are provided for Blockly, Flowchart and BASIC programming options.
To view the included samples files within ‘PICAXE Editor 6’ use the File>Open Samples menu and
select ‘AXE171 – PICAXE 14 Audio Kit’

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4.1 Switching the LEDs on and off
4.1.0 What is an LED?
A Light Emitting Diode (LED) is an electronic component that
gives out light when current passes through it. An LED is a special
type of diode. A diode is a component that only allows current to
flow in one direction.
Therefore when using a diode, it must always be connected the
correct way around.
The positive (anode) leg of an LED is longer than the negative (cathode) leg (shown by the bar on the
symbol). The negative leg also has a flat edge on the plastic casing of the LED.
4.1.1 What are LEDs used for?
LEDs are mainly used as indicator lights. Red and green LEDs are commonly used on electronic
appliances like televisions to show if they are switched on or in 'standby' mode. LEDs are available in
many different colours, including red, yellow, green and blue. Special 'ultrabright' LEDs are used in
safety warning devices such as the 'flashing lights' used on bicycles. Infra-red LEDs produce infra-red
light that cannot be seen by the human eye but can be used in devices such as video remote-
controls.
4.1.2 Using LEDs.
LEDs only require a small amount of current to work, which makes them
much more efficient than bulbs (this means, for instance, that if powered
by batteries the LEDs will light for a much longer time than a bulb would).
If too much current is passed through an LED it will be damaged, and so
LEDs are normally used together with a 'series' resistor that protects the
LED from too much current.
The value of the resistor required depends on the battery voltage used. For a 4.5V battery pack a
330R resistor can be used, and for a 3V battery pack a 120R resistor is appropriate.
4.1.3 Connecting the LED to a PICAXE microcontroller
Because the LED only requires a small amount of current to operate, it can be directly connected
between the microcontroller output pin and 0V (with the series protection resistor).