FM radio API

Introduction

chumbradiod is a small daemon application that hosts information about a Chumby radio over HTTP, and also allows for real time configuration of the FM radio parameters.

Status Usage

chumby:/# service_control chumbradiod start

You should then be able to access the status of the chumby radio by opening any web browser to the page

http://ip:8081/radio/status.xml

. To get debugging information, you need to first convince the controlpanel that chumbradiod is actually running. To do this, run

echo 1 > /var/services/chumbradiod/pids

, and then just run

chumbradiod

.

Status Response

You will receive an XML response giving the current FM radio status...

• Example 1 (device found)

<radio found="1" tuned="1" station="104.7" stereo="0" signal="20" signal_max="256" volume="15" volume_max="15" seek_threshold="20" seek_threshold_max="255" spacing="200" band="US/Europe">
    <station freq="90.70"/>
    <station freq="94.10"/>
    <station freq="94.90"/>
    <station freq="95.70"/>
    <station freq="96.50"/>
    <station freq="102.10"/>
    <station freq="102.90"/>
    <station freq="103.70"/>
</radio>

• Example 2 (device found, RDS enabled)

<radio found="1" tuned="1" station="105.3" stereo="1" signal="105" signal_max="256" seek_threshold="0" seek_threshold_max="255"
spacing="200" band="US/Europe" callsign="KCNL" programservice="RADIO   " ptycode="Rock" radiotext0=" SAVE YOUR RADIO DOT ORG" radiotext1=""
juliandate="0" hour="0" minute="0" localtime="0:00">
    <station freq="105.30"/>
    <station freq="105.50"/>
    <station freq="105.70"/>
    <station freq="106.50"/>
    <station freq="107.50"/>
</radio>

• Example 3 (device not found)

<radio found="0"/>

Configuration Usage

You can also configure the radio using an HTTP query string

http://ip:8081/radio/configure

There are several commands available...

• Set radio station

http://ip:8081/radio/configure?station=94.9

• Seek radio up

http://ip:8081/radio/configure?seek_up=1

• Seek radio down

http://ip:8081/radio/configure?seek_down=1

• Enable RDS support in status messages. Note this will cause chumbradiod to use about 2% more CPU.

http://ip:8081/radio/configure?rds=1

• Set seeking strength. You probably want this to be very low.

http://ip:8081/radio/configure?seek_strength=20

• Refresh the list of available stations

http://ip:8081/radio/configure?rescan=1

• Turn on the radio and begin playing through the speakers

http://ip:8081/radio/configure?power=1

• Set the country, which defines tuning frequency ranges. Note you'll probably want to issue a rescan at the same time.

http://ip:8081/radio/configure?country=usa

http://ip:8081/radio/configure?country=japan

http://ip:8081/radio/configure?country=china

• Lock the configuration interface with key 12345. Note that once locked, you'll need to specify the same "key" every time you issue a "configure" request. Unlock by sending the key, along with "lock=0".

http://ip:8081/radio/configure?key=12345&lock=1

You may set multiple options at once. The last option part will take affect.

• Configure multiple options

http://ip:8081/radio/configure?station=94.9&power=1

Configuration Response

You will receive a response in the form of XML, notifying the result of each configuration command...

• example 1 [all success]

<result-list>
  <result command="station" status="success"/>
  <result command="power" status="success"/>
</result-list>

• example 2 [partial success, partial failure]

<result-list>
  <result command="station" status="failure"/>
  <result command="power" status="success"/>
</result-list>

Note that you will only receive a result for commands you have sent in the query string.