Kitronik Igloo Safety guide

Igloo: PICAXE wearable module Starter Guide
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Electro-Fashion: Igloo, PICAXE wearable module Starter Guide
Introduction
The Igloo: PICAXE wearable module has been designed specifically for use in E-textiles projects and provides a cost
effective, fun way to learn about electronics and programming in a textiles environment.
The board uses a PICAXE14M2 microcontroller. This is a chip that can be programmed using the free PICAXE
Programming Editor software to respond to various inputs like switches and sensors and control outputs like LEDs or
buzzers.
This guide will provide all the information you need to get started with the Igloo PICAXE wearable module.

Igloo: PICAXE wearable module Starter Guide
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Hardware
The Igloo PICAXE wearable module has 6 I/O pins.
The three on the left (C.4, C.1 and C.0) have pull-down resistors on the board. This means you can attach a switch
between the “+” pad at the top or bottom of the board and any of those inputs and have a switch which goes high
when closed and low when opened.
The three on the right (B.3, B.4 and B.5) have no pull-down resistors so they can be connected to analogue inputs
such as our Light Sensor or a potentiometer.
All six can also be used as outputs if required.
The processor input C.3 is connected to the on-board push switch. The pin is normally low, going high when the
switch is pressed.
The processor pin B.2 is connected to the on-board LED.

Igloo: PICAXE wearable module Starter Guide
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Connections
Name
Description
Additional Features
C.0
I/O pin with 10K pull-down resistor
ADC, Touch, PWM, hPWM
C.1
I/O pin with 10K pull-down resistor
hPWM
C.3
On-board switch with built in pull-
down
C.4
I/O pin with 10K pull-down resistor
Touch, ADC
B.2
White LED with current limit resistor
PWM
B.3
I/O pin with ADC, no pull-down
ADC, Touch
B.4
I/O pin with ADC, no pull-down
ADC, PWM, Touch
B.5
I/O pin with ADC, no pull-down
ADC, Touch, hPWM
“-“
Negative/GND from battery
“+”
Positive voltage from battery
Thermal Reset fuse hold current =
100mA
CONN1
3.5mm Programming Jack
CONN2
Power connector
2mm JST compatible
Electrical Information
Operating Voltage
2.5-5.5V
Max current per pin (sink or source)
20mA
Max current total for all pins
90mA
Max current draw by on-board LED
20mA @5.5V
Max input impedance for ADC pins
20K Ohms
Min input voltage - Logic HIGH
0.8 x Operating Voltage
Max input voltage - Logic LOW
0.2 x Operating Voltage
Glossary of Terms
ADC –Analog Digital Conversion. This means the pin can read in a voltage and provide a number between 0 and 255.
PWM –Pulse Width Modulation. The pin can pulse on and off very quickly and allows the user to vary the length of
the pulses and also the time between pulses. This is useful for dimming LEDs.
hPWM –Hardware Pulse Width Modulation. The same as PWM but it is capable of pulsing much more quickly,
making it good for sending data or dimming LEDs.
Pull-down resistor –A resistor between the pin and 0V/GND. This pulls the pin to 0V when it isn’t being pulled high
by an input. This ensures the pin is always held in a valid logical state.

Igloo: PICAXE wearable module Starter Guide
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Power
There are several ways you can power your Igloo PICAXE wearable module:
1) The simplest way is with a 2xAAA alkaline batteries in a battery cage with JST connector. Zinc carbon or
rechargeable NiMH batteries will not work well as they drop in voltage very quickly, meaning any LEDs
attached will start to dim.
2) Alternatively you can sew a coincell power board with battery to the “+” and “-”pads at the top or bottom of
the board using our conductive thread.
3) Or a 3.7V rechargeable LiPo battery with a 2mm JST connector will also work.
2xAAA Sewable Coincell Rechargeable LiPo
Programming
+ Longer battery life
+ Low cost
+ Slim profile
+ Lightweight
+ Long battery life
+ Slim Profile
- Bulky
- Heavy
- Shorter Battery Life
- Sewing required
- Special charger required
- Higher initial cost

Igloo: PICAXE wearable module Starter Guide
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Important: To program the board you will need a USB PICAXE Programming Cable (available here).
You will also need the correct software. Download the latest version of the PICAXE Programming Editor, our quick
start page has a link.
Install and run the program, then click “New Blockly” in the top left corner to open the Blockly interface.
From here you can browse the available blocks in the categories down the left hand side and arrange them into
programs in the space to the right. Remember to connect to the green “start” block.
Once your code is complete, check the settings at the far left of the screen. Make sure you have the correct COM
port selected from the dropdown menu (it will be the one that says PICAXE USB). Also check you have the correct
chip type selected (PICAXE 14M2).

Igloo: PICAXE wearable module Starter Guide
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Check the programming cable is fully inserted into the Igloo PICAXE wearable module and that the board has a
power supply attached then click the “Program” icon near the top of the screen. A green progress bar will appear at
the bottom right of the screen and it will inform you when the code has successfully been uploaded.
The program shown above can be used to check the set-up and will flash the on-board LED.

Igloo: PICAXE wearable module Starter Guide
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Connecting Components
There are two ways to connect the PICAXE Control Board to your other e-textiles components.
Using Crocodile Clips
The fastest way to do this is by using crocodile leads. It is a good idea to test your circuit this way before sewing it
into a project as it is much easier to make changes if your circuit is incorrect.
To connect an output such as an LED simply use one lead to connect the negative leg of your LED to either of the
negative pads on the PICAXE Control Board, and another lead to connect the positive leg of the LED to the output pin
you wish to use.
Using Conductive thread
Once you are happy with your circuit you can use our conductive thread instead of the crocodile leads. The thread
needs to be wrapped tightly around the metal pads on the E-textiles components several times to give a good
connection. Detailed guides on using conductive thread can be found here.

Igloo: PICAXE wearable module Starter Guide
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Hook-up Guide
Below are some simple circuits with accompanying example code to help get you started. The code has been made
using Blockly for PICAXE, but the circuits will work just as well with BASIC or the flowcharts in PICAXE Programming
Editor.
Switch (momentary) –On-board digital input and output
This example demonstrates how to use the on-board push button switch as a momentary switch to turn the on-
board LED on and off. The LED will come on while the button is held down and turn off when the button is released.
Blink –External Digital Output
This example demonstrates how to use an Igloo PICAXE wearable module to make a sewable E-textiles LED flash on
and off.

Igloo: PICAXE wearable module Starter Guide
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Switch (latching) –External digital input and output
This example demonstrates how to use a sewable push button switch as a latching switch to turn a sewable LED on
and off.
Light Sensor –External Analog Input and digital output
This example demonstrates how to use a sewable light sensor to turn the on-board LED off when it gets dark. The
light sensor is facing downward so if you are sewing this into fabric you need to make a hole for the light sensor to
poke through.
In this example we read the input and check to see if it is over 100. In total darkness the reading will be virtually 0
and under a very bright light the reading will be close to 255.

Igloo: PICAXE wearable module Starter Guide
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Fading LED –Pulse Width Modulation
By rapidly turning the LED on and off we can control the brightness. By altering the amount of time the LED spends
on (the duty) we can fade the LED.
In our example the first segment of the code decreases the duty (pulse length) every millisecond until it reaches 5.
Then the second segment does the reverse and increases it until it reaches its original value of 120.
The graphs below show what a dim PWM signal would look like (left) and a brighter PWM signal (right).