JTK – Notes and Ramblings Things we have found …

Back in April I mentioned adding some Roku remote control. At this point I’m thinking more javascript than Python.

Roku has a good External Control Protocol reference online.

Sending commands

Unfortunately, the Roku API will not accept Cross Origin Request. This is not an issue if communicating from Node or Python but from the browser using xhr or fetch() you will get CORS errors. When sending POST for button presses you don’t care about the response for a “mode:’no-cors’ ” will work.

let resp = await fetch("http://roku-ip:8060/keypress/play", {method:'POST', mode:'no-cors'})

For the GET for status from the browser one option is a “proxy” add the “Access-Control-Allow-Origin” header. Borrowing the idea from https://medium.com/gitignore/building-a-roku-remote-web-app-1c0db0056be4 we set our Apache web server.

sudo pico /etc/apache2/apache2.conf to edit the config file and add the following lines:

<Location /roku>
    ProxyPass "http://roku-ip:8060/"
    ProxyPassReverse "/" 
    Header add "Access-Control-Allow-Origin" "*"
</Location>

You will need to have several modules loaded in Apache for this to work: headers and proxy_http. This can be done with:

sudo a2enmod proxy_http
sudo a2enmod headers
sudo systemctl restart apache2

Deep Links

A very important link for launching directly into netflix content is https://unogs.com/search/. From this site you can find the contentid for much of the netflix content.

This allows for directly linking to content with something like:

curl -d '' "http://roku-ip:8060/launch/12?contentid=70136120&mediatype=series"

This is a simple POST to the URL with no body.

The folks at unofficial Netflix online Global Search also provide an API.

We get started with the Sparkfun WRL-15031. The hook-up guide is a good place to start. I am using the  IR Controller ESP8266 firmware.

I don’t have PlatformIO installed so I used the standard Arduino IDE. This was my first time with the ESP8266 so I needed to add the ESP8266 Arduino Core. In the current Arduino IDE this can be done by adding https://arduino.esp8266.com/stable/package_esp8266com_index.json to  the File>Preferences>Additional Boards Manager URLs field of the Arduino IDE. Then using the Board Manager from the Tools > Board menu you can install the esp8266 platform.

Once you have the IDE installed and the board set to Generic ESP8266 you need to make sure you have some libraries installed. ESP8266WebServer, ESP8266WiFi and WiFiManager but you may need to install ArduinoJson, Time and IRremoteESP8266.

It’s time to load the sketch, compile and upload.

The key here is to make sure you set the IO pin definitions correctly.

const int pinr1 = 13; // Receiving pin
const int pins1 = 4; // Transmitting preset 1
const int pins2 = 12; // Transmitting preset 2
const int pins3 = 12; // Transmitting preset 3
const int pins4 = 12; // Transmitting preset 4
const int configpin = 0; // Reset Pin
const int ledpin = 5;

I changed getExternalIP = false; and removed the user_id related and Alex integration code. I set ntpServerName to my internal NTP server. I changed the ntp sync time from 5 minutes to 12 hours near the end of the setup() function: setSyncInterval(43200);.

Once the code is compiled and loaded some testing is needed. On the initial run the ESP will be in AP mode with a SSID of IR Controller Configuration. You can connect and set access point info, hostname, static IP, subnet mask, port, default gateway and passcode.

Once you’re able to connect it is time to find some IR codes. There is a bit of good info in the Tasmota IR page. I found Sony DVD player remotes and some of the IR controlled LED votive candles. There is also good info for Samsung and Vizio TVs online. The codes from http://remotecentral.com often need to be manipulated before they are compatible with the ESP IR library. I created a Excel spreadsheet with worksheets for Vizio, Sony and Samsung.

Once we have the codes we can start controlling things from the web. For example:

http://someip:port/msg=msg?code=E0E040BF:SAMSUNG:32&pass=1234&simple=1

will send a power on/off command of 32 bits in SAMSUNG format. After testing a bit of this I created a simple webpage to send a variety of codes.

There is more Arduino IR blaster info at Ken Shirriff’s blog – post 1 and post 2. For more info on Sony codes refer to https://www.sbprojects.net/knowledge/ir/sirc.php and http://www.hifi-remote.com/sony/.

For the record: Toshiba remote: SE-R0047, Vivio Remote unmarked, Sony Remote RMT-B119A, JVC Remote: RM-S212U.

Sometimes it would be nice to have screen start a detached session at start-up. This isn’t complicated. There are two steps. The first is to create a script to be run in the detached session and make it executable. We’ll call it start.sh.

pico start.sh
chmod +x start.sh

The second is to edit /etc/rc.local to have the script run inside screen at start-up. Add the following line before the exit 0 line.

su - pi -c "screen -dm -S pistartup ~/start.sh"

That’s all there is to it. I found notes on this at https://coderwall.com/p/quflrg/run-a-script-on-startup-in-a-detached-screen-on-a-raspberry-pi.

While these updates were made a while ago they weren’t documented. In the original post on the LaCrosse Weather station, rtl_433 sends mqtt data to our openhab server. On github we found a simple means to get rtl_433 to run as a service.

The core is to update /etc/rtl_433/rtl_433.conf. There is a sample file at conf/rtl_433.example.conf. Most important is the output mqtt... line for example:

output mqtt://jtk-openhab,devices=rtl_433/garage[/model]

If the Pi has multiple dongles you will also need to confirm the device line. Then create /etc/systemd/system/rtl_433-mqtt.service:

[Unit]
Description=rtl_433 to MQTT publisher
After=network.target
[Service]
ExecStart=/usr/local/bin/rtl_433
Restart=always
RestartSec=5
[Install]
WantedBy=multi-user.target

Enable the service with systemctl enable rtl_433-mqtt.service.