It is possible to create custom sketches to use with Breakout. See the readme file in Breakout/custom_examples/ and the rfid_example2.html file in the same directory.

There is also work in progress on a one-wire firmata sketch. See the thread here on the Breakout github page: http://github.com/firmata/arduino/issues/10

Also see this post on the firmata dev list: http://sourceforge.net/mailarchive/message.php?msg_id=30238158. It describes how to create a sketch to communicate with Breakout.

Keep in mind that by using a custom sketch you will not be able to use the Breakout IO objects (unless you specifically implement support for them in your sketch… which is difficult), you will only be able to send and receive sysex and string messages.

You only get Pin change events for inputs (such as buttons, potentiometers, etc). You should use an input (potentiometer) to drive an action, not an output (led). What you need to do is listen for a change event on the Potentiometer (or better yet use a triggerPoint filter – see Breakout/examples/filters/triggerpoint.html). When the threshold is crossed on the rising edge (transition of 0 -> 1 when using triggerpoint filter), set pin 13 to HIGH and do something on your website, when the threshold is crossed on the falling edge, set pin 13 to LOW. The triggerpoint filter is helpful in eliminating jitter that you can observe when using an analog input.

This is possible using the pin state query. You need to request the pin state from the Arduino and you will need to do this by polling:

arduino.addEventListener(IOBoardEvent.PIN_STATE_RESPONSE, onPinStateResponse);
// check pin state every second
setInterval(function () {
arduino.queryPinState(arduino.getDigitalPin(13));
}, 1000);

function onPinStateResponse(event) {
// note here that you use the state rather than the value property
console.log(“pin state = ” + event.pin.state);
}

However, the challenge is writing a Firmata sketch that will do what you want. If this is the only action you need to do for you’re application, there is an easier way. See Breakout/custom_examples/simple_json.html and the accompanying Firmata sketch in Breakout/custom_examples/sketches/SimpleFirmataJSON. Upload the sketch to your arduino, start Breakout Server and open simple_json.html in your browser. This demonstrates how to use a custom sketch to send a JSON string to the arduino and then simply handle it as you would any other JSON string. In your case you wouldn’t want to listen for the SYSTEM_RESET event and reset the counter since this would reset the counter when the browser is refreshed, but other than that this should enable you to do what you are looking to do and is much easier than trying to modify AdvancedFirmata or StandardFirmata.