im new in ionic, right now i'm trying to send a "code" in string.
which the string consist of a few packets data in HEX.
eg. V1-FC03-2ED1-FE01
V1 is the sequence, then after the first - is the first packet "FC03"
the code successfully send to my arduino using serial monitor on pc.
arduino serial monitor
now i want to send it trough BLE using ionic.
i follow the example on github on doing the BLE.
it works if send 1 or 0.
here is the function in ionic codes that going to send to arduino after button pressed
onPowerSwitchChange(event) {
console.log('onPowerSwitchChange');
let value = this.power ? 1 : 0;
let buffer = new Uint8Array([value]).buffer;
console.log('Power Switch Property ' + this.power);
this.ble.write(this.peripheral.id, LIGHTBULB_SERVICE, SWITCH_CHARACTERISTIC, buffer).then(
() => this.setStatus('Light is ' + (this.power ? 'on' : 'off')),
e => this.showAlert('Unexpected Error', 'Error updating power switch')
);
}
here i tried to change
let value = this.power ? 1 : 0;
to
let value = "V1-FC03-2ED1-FE01";
but when compile, got error
Argument of type 'string[]' is not assignable to parameter of type 'ArrayBuffer'. Property 'byteLength' is
missing in type 'string[]'.
L68: let value = "V1-FC03-2ED1-FE01";
L69: let buffer = new Uint8Array([value]).buffer;
L70: console.log('Power Switch Property ' + this.power);
hopefully someone can help me on this problem
Not sure if this will help you as I'm not a programmer by trade... but I wanted to send a "2" as string and it turned out that I had to do it like this:
var data = new Uint8Array(1);
data[0] = 50;
With 50 being the Uint8Array equivalent of 2
Currently I'm trying to read from the BLE in the opposite direction to no effect so please keep us posted as to your progress.
Related
Hi
I'm learning to use websocket client in arduino ESP32 board. I can receive and emit text in this form, ""text"" as i can show here.
socketIO.emit("emitevent", "\"this is a message from the client\"");
or
char* Name = "\"Carlos\"";
webSocket.emit("newEmitEvent", Name);
I would like to charge a variable String to send it but i cant find the way. For example,
String Values;
Values = 00:a3:45;
webSocket.emit("newEmitEvent", Values);
But I can't see how to do it,
Can you help me,
please?
Thanks
I've solved with,
Values += """\"";
Values += 00:a3:45;
Values += "," // if i'm in a loop
Values += "\"";
But, it is a clean solution?
Thanks,
How can I do a function to get the current year with 4 digits using ELM 0.19.1? I have read something but nothing works with 0.19.1.
Signature:
getCurrentYear : Int
Execution:
getCurrentYear => 2020
Edit:
Maybe executing new Date().getFullYear() javascript code?
The simplest way would be to pass the year in via flags when you start the app, since the current year isn't likely to change in the course of the application running. In that case, you can use the snippet of JavaScript you suggested (ellie example):
Elm.Main.init({
node: document.querySelector('main'),
flags: {
year: new Date().getFullYear(),
}
});
module Main exposing (main)
import Browser
import Html exposing (Html, p, text)
type alias Flags =
{ year : Int }
main : Program Flags Model Msg
main =
Browser.element
{ init = \flags -> ( Model flags.year, Cmd.none )
, view = view
, update = update
, subscriptions = \_ -> Sub.none
}
type alias Model =
{ year : Int }
type Msg
= NoOp
update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
case msg of
NoOp ->
( model, Cmd.none )
view : Model -> Html Msg
view model =
p [] [ text "The year is ", text (String.fromInt model.year) ]
Alternatively, you can use Time.now to request the current time, as Robin Zigmond's answer suggests, however that is pointing to Elm 0.18 documentation (for elm-lang/core instead of elm/time). For 0.19, you need both a Time.Posix and a Time.Zone in order to call Time.toYear. You can chain Time.now (a Task producing a Posix value) and Time.here (a Task producing a Zone with the current time zone offset) to retrieve those values in one Cmd. Here's an example (also on ellie)
module Main exposing (main)
import Browser
import Html exposing (Html, p, text)
import Task exposing (Task)
import Time
type alias Flags =
{ year : Int }
main : Program () Model Msg
main =
Browser.element
{ init = \() -> ( Model 0, whatYearIsIt |> Task.perform GotYear )
, view = view
, update = update
, subscriptions = \_ -> Sub.none
}
whatYearIsIt : Task x Int
whatYearIsIt =
Task.map2 Time.toYear Time.here Time.now
type alias Model =
{ year : Int }
type Msg
= GotYear Int
update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
case msg of
GotYear year ->
( { model | year = year }, Cmd.none )
view : Model -> Html Msg
view model =
p [] [ text "The year is ", text (String.fromInt model.year) ]
As I already said in my comment, it's impossible to define a function in Elm that returns the current year. You have to get such information from the Elm runtime system (which is basically JavaScript, but you don't have to write it yourself). This happens via commands, where you tell the runtime system to do something for you. But note that you can't simply retrieve the "return value" of that command and get it back into your Elm code. Instead you have to pass it into a function that can convert it into a "message" (see basic Elm Architecture tutorial here, it's fundamental to understand this before you can do anything with Elm) - this then allows you to store the value in your Model and thereby display it in your app.
These patterns do take some getting your head around, especially if you're not used to pure functional programming - but once you get used to it the benefits are huge, including a near guaranteed absence of runtime errors, and greatly enhanced ability to reason about your code.
For getting the year specifically, it looks like you need this library, which gives you (as now) a Task rather than a Cmd. You can use Task.perform to convert it to a command, which is documented here - in fact it even gives an example that matches your use case quite closely - I'll copy it here for posterity:
import Time -- elm install elm/time
import Task
type Msg
= Click
| Search String
| NewTime Time.Posix
getNewTime : Cmd Msg
getNewTime =
Task.perform NewTime Time.now
You'll have to fill this in to fit your own use case, in particular your own Msg type. But it gives a good basic outline. To get the user's current year, you need to replace the Time.Posix type with Int, and the Time.now command with (Task.map2 Time.toYear Time.here Time.now), as explained by #bdukes in his answer.
Trying to do some Swift stuff. Converting some USB device detection code from Objective-C to Swift. Having a problem with getting the Notification port. IONotificationPortCreate returns a Unmanaged<'IONotificationPort'>! and when the program runs it hangs on line 2 below and I then printed out the description of notify and notifyPort below. I don't know if it's not getting the port or if I'm not getting it out of that Unmanaged <'IONotificationPort'>! correctly or something else is wrong
var notify = IONotificationPortCreate(kIOMasterPortDefault)
var notifyPort = notify.takeRetainedValue() as IONotificationPortRef
Printing description of notify: (Unmanaged<'IONotificationPort'>!) notify = (_value = <no summary available>)
Printing description of notifyPort: (IONotificationPortRef) notifyPort = 0x000000010050e620 {}
Thanks for any help,
Chris
I am having a java program send data to me over a specific socket to my node.js application. I want to be able to obtain all of the data, which is information from a SQlite database, and send it off to something else.
I've found something like the following can work but it seems to be unreliable as data is missing and sometimes it doesn't even show up.
stream.addListener('data', function(data){
buffer.write(data.toString());
});
on a side note, I need the socket to stay open so I can't call the "end" event.
I really don't have any attachment to stream.addListener so i can use something else if it works how i want. Basically what i'm asking is, What is the most effective way to obtain data from a socket using node.js?
P.S. thank you for your time
The data event is not guaranteed to have all the data sent to it in one go. You'll need to build up a buffer over multiple events and watch for delimiters of some kind (newlines, null characters, whatever you feel). Here's an example from a project where I'm parsing data from IRC (converted from CoffeeScript); parseData is the event handler for the data event (e.g. socket.on('data', this.parseData);):
IrcConnection.prototype.parseData = function(data) {
var line, lines, i;
data = data.replace("\r\n", "\n");
this.buffer += data;
lines = this.buffer.split("\n");
this.buffer = "";
/* Put the last line back in the buffer if it was incomplete */
if (lines[lines.length - 1] !== '') {
this.buffer = lines[lines.length - 1];
}
/* Remove the final \n or incomplete line from the array */
lines = lines.splice(0, lines.length - 1);
for (i = 0; i < lines.length; i++) {
line = lines[i];
this.emit('raw', line);
}
};
I'm trying to read weight from Sartorius Weighing Scale model No BS2202S using the following code in C#.net 2.0 on a Windows XP machine:
public string readWeight()
{
string lastError = "";
string weightData = "";
SerialPort port = new SerialPort();
port.PortName = "COM1";
port.BaudRate = 9600;
port.Parity = Parity.Even;
port.DataBits = 7;
port.StopBits = StopBits.One;
port.Handshake = Handshake.RequestToSend;
try {
port.Open();
weightData = port.ReadExisting();
if(weightData == null || weightData.Length == 0) {
lastError = "Unable to read weight. The data returned form weighing machine is empty or null.";
return lastError;
}
}
catch(TimeoutException) {
lastError = "Operation timed out while reading weight";
return lastError;
}
catch(Exception ex) {
lastError = "The following exception occurred while reading data." + Environment.NewLine + ex.Message;
return lastError;
}
finally {
if(port.IsOpen == true) {
port.Close();
port.Dispose();
}
}
return weightData;
}
I'm able to read the weight using Hyperterminal application (supplied with Windows XP) with the same serial port parameters given above for opening the port. But from the above code snippet, I can open the port and each time it is returning empty data.
I tried opening port using the code given this Stack Overflow thread, still it returns empty data.
Kindly assist me.
I know this is probably old now ... but for future reference ...
Look at the handshaking. There is both hardware handshaking and software handshaking. Your problem could be either - so you need to try both.
For hardware handshaking you can try:
mySerialPort.DtrEnable = True
mySerialPort.RtsEnable = True
Note that
mySerialPort.Handshake = Handshake.RequestToSend
I do not think sets the DTR line which some serial devices might require
Software handshaking is also known as XON/XOFF and can be set with
mySerialPort.Handshake = Handshake.XOnXOff
OR
mySerialPort.Handshake = Handshake.RequestToSendXOnXOff
You may still need to enable DTR
When all else fails - dont forget to check all of these combinations of handshaking.
Since someone else will probably have trouble with this in the future, hand shaking is a selectable option.
In most of the balances you will see the options for Software, Hardware 2 char, Hardware 1 char. The default setting for the Sartorius balances is Hardware 2 Char. I usually recommend changing to Software.
Also if it stops working all together it can often be fixed by defaulting the unit using the 9 1 1 parameter. And then resetting the communication settings.
An example of how to change the settings can be found on the manual on this page:
http://www.dataweigh.com/products/sartorius/cpa-analytical-balances/