In this document, we will discuss various features LEDI. We will explain how to set it up and operate it. From here on, we will assume you have a completely assembled LEDI. We also assume you have an Android phone that can be used to communicate with LEDI.
Most features of LEDI can be controlled via Android App, LEDI Manager. It gives you the ability to interact with it without much fuss, and gives you intuitive control over electronics circuit you’ve assembled.
First download the App from Google Play:
Power up LEDI
Simply turn the power switch to the "on" position. Also, make sure the power supply voltage switch is set to "5v".
When it’s first powered up, LEDI will go into a clock mode. The clock starts at "00:00", since LEDI does not keep track of time when it’s powered off. Once powered on, however, it will constantly keep accurate time across various operating modes. Also in addition to HH:MM clock digits, you will see the binary indicator ticking every second.
First, make sure Bluetooth radio is turned on in Settings.
Everytime LEDI’s power is reset, the bluetooth module will go into discoverable mode. Other bluetooth devices can easily scan and pair with LEDI. You will first need to pair LEDI with your Android device.
Let’s first "bond" with LEDI using an Android phone. Go to:
Settings -> Wireless Settings -> Bluetooth Settings
Hit scan for devices. Your device should show up and it will be called either
Select the device and you will get a bluetooth pairing request. Use the passcode 1234 to establish the pairing.
LEDIManager Android App
We have written an Android app specifically designed to work with LEDI. This app is the main controller for LEDI which allows it to communicate with the "world".
LEDIManager sends various notifications from your Android phone to LEDI. It maintains stable connection to LEDI and allows user to interact with LEDI wirelessly.
The current list of LEDIManager features:
- Gmail, sms, call, alarm notifications supported
- Remotely set current time
- Send arbitrary message from your Android phone
- Virtual interface that allows you to "draw" on LEDI wirelessly
When you start the app
Your app will look like this:
First search for your LEDI and bond with it, by pressing the "Search" button on the App. If you haven’t already paired against it, it will prompt you for the passcode for pairing. (Remember 1234 to pair)
Once the search is done, select your LEDI. After your device is selected, it will bring you back to the main screen.
Press the large button on top that says "service off". It’s a toggle button that will turn green when the connection is properly established. If successful, your screen will look like this, and LEDI will greet you with a chime.
You can send simple messages to LEDI from a text box on the bottom of the screen, and then hitting "Send". This will scroll your text across LEDI.
Other Android Apps
There are slew of available Android Apps that just works with LEDI. Almost all of them are free. For example, I’ve tested:
LEDI uses Bluetooth module that understands SPP (Serial Port Profile). What this basically means is that it’s compatible with lots of bluetooth-enabled software out there.
Talk to it
Try downloading BlueTerm from the App store on your phone. I found it to be the simplest one to use when I was testing LEDI.
- Open the App
- Hit settings button on your phone
- Tap "Connect device"
- Tap "Scan for devices"
- Your LEDI will show up as one of the devices as "linvor" or "LEDI_XXX"
- It will say "Connected to <your_device>"
- Type something on the terminal
- Hit "enter" on your virtual keyboard
If everything went right, you will see the message you just typed scroll across LEDI.
There are 2 slide switches on the board. With the barrel jack faced down, the slide switch left of it is "on/off" switch. The slide switch to the right of the barrel jack is the "3v/5v" toggle switch. Slide the power switch up to turn the power on and supply regulated 5 volts to the circuit.
The power circuit supplies either 5v or 3.3v of clean DC. There are access headers to either
- source power from other external voltage source (upto 9VDC)
- supply power to other circuits (5 or 3.3v)
We’ve taken the power schematics from Sparkfun‘s breadboard power supply.
You can source power from an external battery through the connector shown in the picture:
Or you can supply regulated power to other circuits through these pins on the PCB:
For example, I am powering the Arduino via the power output pins: