diff --git a/hardware/BBB/145-BBB-hardware.html b/hardware/BBB/145-BBB-hardware.html
index ac59dcd3..bad622aa 100644
--- a/hardware/BBB/145-BBB-hardware.html
+++ b/hardware/BBB/145-BBB-hardware.html
@@ -101,10 +101,10 @@ voltage ten times in rapid succession for each input message and output the mean
var container = $('', {style:"margin:0; padding:4px; padding-left 10px;"});
var row = $('').appendTo(container);
var breakpointField = $('').appendTo(row);
- var inputValueField = $('',
- {disabled:"", class:"node-input-breakpoint-input-value", type:"text", style:"margin-left:5px; margin-right:2px; width:36%;"}).appendTo(breakpointField);
+ var inputValueField = $('',
+ {disabled:"", class:"node-input-breakpoint-input-value", type:"text", style:"margin-left:5px; margin-right:2px; width:36%;"}).appendTo(breakpointField);
if (breakpoint.mutable) {
- inputValueField.removeAttr("disabled");
+ inputValueField.removeAttr("disabled");
}
breakpointField.append(" => ");
var outputValueField = $('',
@@ -126,17 +126,17 @@ voltage ten times in rapid succession for each input message and output the mean
mutableFlag.attr("mutable", "false");
}
if (insert === true) {
- var last = $("#node-input-breakpoint-container").children().last();
- var prev = last.prev();
- inputValueField.val((Number(last.find(".node-input-breakpoint-input-value").val()) +
- Number(prev.find(".node-input-breakpoint-input-value").val()))/2);
- outputValueField.val((Number(last.find(".node-input-breakpoint-output-value").val()) +
- Number(prev.find(".node-input-breakpoint-output-value").val()))/2);
- last.before(container);
+ var last = $("#node-input-breakpoint-container").children().last();
+ var prev = last.prev();
+ inputValueField.val((Number(last.find(".node-input-breakpoint-input-value").val()) +
+ Number(prev.find(".node-input-breakpoint-input-value").val()))/2);
+ outputValueField.val((Number(last.find(".node-input-breakpoint-output-value").val()) +
+ Number(prev.find(".node-input-breakpoint-output-value").val()))/2);
+ last.before(container);
} else {
- inputValueField.val(breakpoint.input);
- outputValueField.val(breakpoint.output);
- $("#node-input-breakpoint-container").append(container);
+ inputValueField.val(breakpoint.input);
+ outputValueField.val(breakpoint.output);
+ $("#node-input-breakpoint-container").append(container);
}
}
diff --git a/hardware/BBB/145-BBB-hardware.js b/hardware/BBB/145-BBB-hardware.js
index 966198c7..9f18c82b 100644
--- a/hardware/BBB/145-BBB-hardware.js
+++ b/hardware/BBB/145-BBB-hardware.js
@@ -35,46 +35,46 @@ function AnalogInputNode(n) {
this.breakpoints = n.breakpoints;
this.averaging = n.averaging;
if (this.averaging) {
- this.averages = 10;
+ this.averages = 10;
} else {
- this.averages = 1;
+ this.averages = 1;
}
// Define 'node' to allow us to access 'this' from within callbacks
var node = this;
- // Variables used for input averaging
- var sum; // accumulates the input readings to be averaged
- var count; // keep track of the number of measurements made
-
+ // Variables used for input averaging
+ var sum; // accumulates the input readings to be averaged
+ var count; // keep track of the number of measurements made
+
// The callback function for analogRead. Accumulates the required number of
// measurements, then divides the total number, applies output scaling and
// sends the result
var analogReadCallback = function (x) {
- sum = sum + x.value;
- count = count - 1;
- if (count > 0) {
- bonescript.analogRead(node.pin, analogReadCallback);
- } else {
- var msg = {};
- msg.topic = node.topic;
- sum = sum/node.averages;
- // i is the index of the first breakpoint where the 'input' value is strictly
- // greater than the measurement (note: a measurement can never be == 1)
- var i = node.breakpoints.map(function (breakpoint) { return sum >= breakpoint.input; }).indexOf(false);
- msg.payload = node.breakpoints[i-1].output + (node.breakpoints[i].output - node.breakpoints[i-1].output) *
- (sum - node.breakpoints[i-1].input)/(node.breakpoints[i].input - node.breakpoints[i-1].input);
- node.send(msg);
+ sum = sum + x.value;
+ count = count - 1;
+ if (count > 0) {
+ bonescript.analogRead(node.pin, analogReadCallback);
+ } else {
+ var msg = {};
+ msg.topic = node.topic;
+ sum = sum/node.averages;
+ // i is the index of the first breakpoint where the 'input' value is strictly
+ // greater than the measurement (note: a measurement can never be == 1)
+ var i = node.breakpoints.map(function (breakpoint) { return sum >= breakpoint.input; }).indexOf(false);
+ msg.payload = node.breakpoints[i-1].output + (node.breakpoints[i].output - node.breakpoints[i-1].output) *
+ (sum - node.breakpoints[i-1].input)/(node.breakpoints[i].input - node.breakpoints[i-1].input);
+ node.send(msg);
}
};
// If we have a valid pin, set the input event handler to Bonescript's analogRead
if (["P9_39", "P9_40", "P9_37", "P9_38", "P9_33", "P9_36", "P9_35"].indexOf(node.pin) >= 0) {
node.on("input", function (msg) {
- sum = 0;
- count = node.averages;
- bonescript.analogRead(node.pin, analogReadCallback);
- });
+ sum = 0;
+ count = node.averages;
+ bonescript.analogRead(node.pin, analogReadCallback);
+ });
} else {
node.error("Unconfigured input pin");
}
diff --git a/hardware/BBB/README.md b/hardware/BBB/README.md
new file mode 100644
index 00000000..a08281c3
--- /dev/null
+++ b/hardware/BBB/README.md
@@ -0,0 +1,106 @@
+# BBB-hardware
+
+Node-RED nodes for interfacing with hardware inputs and outputs on the BeagleBone Black.
+Uses the bonescript library provided with the BBB, available through NPM and on Github
+at
+
+## Installation and Requirements
+
+The BBB should be running with the as-supplied device tree compiled into the kernel. This
+code is not currently aware of dynamically loaded device tree overlays, and in particular
+the list of pins presented for each node is based on the default. You might be lucky though...
+
+You need to be root to use bonescript, an error message will be logged if you are not.
+
+This code has been tested with the latest node-RED from github as of 2014-02-27T20:00
+using bonescript 0.2.4 running under node v0.8.22 on Angström
+Linux 3.8.13. The BBB was reflashed with the 2013.09.04 image, updated using opkg upgrade.
+
+Note that you do not need to add bonescript to node-RED's global context (in settings.js) to
+use these nodes, but no harm should arise if you do.
+
+Currently there are no checks against assigning the same pin to multiple nodes. Don't do it!
+
+## Available Nodes
+
+More nodes will be added as time is available, but the list at present is:
+
+### analogue-in
+
+Uses the on-chip ADC to measure a voltage between 0V and +1.8V on any one of the 7
+dedicated input pins. A message input is used to trigger an ADC conversion, or
+alternatively a single message can trigger a rapid 'burst' of 10 conversions
+which are averaged together to reduce the noise (which can be a problem, especially
+with high source impedances).
+
+Linear scaling can be applied to the measurement result. Linearity correction can
+be applied using a piecewise-linear approach, useful for linearising transducers such
+as thermistors or LDRs.
+
+Useful for conversion rates up to about 50 samples/sec.
+
+### discrete-in
+
+Reads a GPIO pin, and generates a message when it changes state: either in both
+directions or just rising or just falling edges only. A debounce algorithm may be
+applied, useful if the input is connected to a pushbutton.
+
+One pin state is denoted as 'active', and the node accumulates the total time in this
+state. A message with this total is output periodically, controlled by an internal
+timer. The total can be cleared or set to an arbitrary value by an input message
+who's topic copntains 'load'.
+
+Useful for energy monitoring, e.g. logging boiler on time.
+
+### pulse-in
+
+Counts input pulses at a GPIO pin. The count can be advanced by either the rising edge
+of the pulse, or by both edges. Two outputs are provided:
+
+1. The current total number of pulses
+2. The current pulse rate (pulses/second)
+
+Separate scaling factors are applied to each output. Output messages are generated
+at regular intervals, controlled by an internal timer. The count can be cleared
+or set to an arbitrary value by an input message who's topic copntains 'load'.
+
+Useful for energy monitoring, e.g. electricty meter pulse outputs.
+
+The 'instantaneous' pulse rate is derived from either the time between the last two
+pulses, or the time since the last pulse, whichever is larger. This gives a rapid
+dynamic response to changes in electricty use, for example.
+
+Recommended maximum pulse rate 20 pulses/second - but it did work OK at 500 Hz!
+
+### discrete-out
+
+Sets a GPIO pin to the state specified by the input message payload: 0/1 or true/false.
+The pin can either follow the input state or be an inverted copy. Alternatively, in toggle
+mode each input message (whatever its topic & payload) will toggle the pin between
+the two states.
+
+You can specify the state to be set at startup, prior to the arrival of the first message.
+
+The node generates an output message with payload 1 or 0 each time it changes state.
+The user LEDs are available to the discrete-out node
+
+### pulse-out
+
+Pulses a GPIO pin when a message arrives. The pulse time is set in the property editor,
+but can be overridden by a time value in an input message (topic containing 'time').
+
+The can be set to generate high pulses (normally low) or vice-versa. It may also be
+set as retriggerable or not.
+
+The node generates an output message with payload 1 or 0 each time it changes state.
+The user LEDs are available to the pulse-out node
+
+## Author
+
+BBB-hardware was written by
+
+* Max Hadley [@MRHadley](http://twitter.com/MRHadley)
+
+## Copyright and license
+
+Copyright 2014 M R Hadley, made available under [the Apache 2.0 license](LICENSE).