Radio events (how?)

[Sanoski]

This is might seem like a weird question. I'm curious how the radio
works in my new car. I have a 2008 Scion. On the steering wheel are
buttons to control the radio: up, down, and mode. Pressing mode merely
allows you to set the audio preferences. The up and down are obvious.
Press up changes the stations. But it only scans through your presets.
It only seeks if you hold down the one of the corresponding keys. This
is kind of annoying. I'd rather it do the exact opposite. When you
press it it immediately seeks to open stations, and if you hold it
down then it'll scan your presets. It's probably possible to change it
somehow. If only I knew how it was implemented.

I called Toyota, and the guy is gonna send me a circuit diagram. But I
still need some ideas. If you have any feel free to shoot them my way.
How would you approach such a problem? How would you figure out how
it's implemented?

 

[[email protected]]

This is might seem like a weird question. I'm curious how the radio
works in my new car. I have a 2008 Scion. On the steering wheel are
buttons to control the radio: up, down, and mode. Pressing mode merely
allows you to set the audio preferences. The up and down are obvious.
Press up changes the stations. But it only scans through your presets.
It only seeks if you hold down the one of the corresponding keys. This
is kind of annoying. I'd rather it do the exact opposite. When you
press it it immediately seeks to open stations, and if you hold it
down then it'll scan your presets. It's probably possible to change it
somehow. If only I knew how it was implemented.

I called Toyota, and the guy is gonna send me a circuit diagram. But I
still need some ideas. If you have any feel free to shoot them my way.
How would you approach such a problem? How would you figure out how
it's implemented?

I would assume it's implemented in the firmware of the radio, inside
the radio itself.
I guess it could be dedicated logic, but my guess is the overall
complexity points to some
sort of processor running a firmware. As for changing it... doubt it
would be easy.

If I'm understanding the behavior right though, you might be able to
make something to put
inline between the button and the radio that would "record" your
action and then "play back"
the opposite. Ie, if you push the button quickly, it simulates a push
long enough to cause a
frequency scan; if you hold the button down, it simulates a quick push
to cause a channel scan.

But this might introduce an annoying delay in operation. And if the
meaning of the buttons is different in different operating modes, this
could also cause problems as your gizmo wouldn't know the state of the
radio.

As for how to do it... could probably do something with timer ICs, but
realistically, a little microcontroller.

 

[pipedown]

I would assume it's implemented in the firmware of the radio, inside
the radio itself.
I guess it could be dedicated logic, but my guess is the overall
complexity points to some
sort of processor running a firmware. As for changing it... doubt it
would be easy.

If I'm understanding the behavior right though, you might be able to
make something to put
inline between the button and the radio that would "record" your
action and then "play back"
the opposite. Ie, if you push the button quickly, it simulates a push
long enough to cause a
frequency scan; if you hold the button down, it simulates a quick push
to cause a channel scan.

But this might introduce an annoying delay in operation. And if the
meaning of the buttons is different in different operating modes, this
could also cause problems as your gizmo wouldn't know the state of the
radio.

As for how to do it... could probably do something with timer ICs, but
realistically, a little microcontroller.

That wiring diagram will show you how its physically connected and if it
includes names for the signal wires might also give you some clues to the
actual technology used. You're probably hoping there is a direct wire
between the radio and control pod to which you can swap wires or something.
Unlikely but possible.

In an 08 car many controls operate on the car's CAN bus. Broadly speaking
this is sort of like a USB bus but any device can be a host or client. The
control pod transmits control codes onto the bus and the radio interprets
them as required. In theory, you could reprogram the radio firmware to do
other things with the input but the software and code you would need to do
that are Toyota property and unlikely to ever see the public domain.

If the wiring diagram agrees that the control pod is a local microprocessor
controlled CAN bus device then you may want to do a little research on the
protocol and maybe buy a PC based CAN bus reader/monitor (not a handheld
unit, too limited) to view the activity on the bus. Mostly people think of
CAN bus in terms of replacing the functions of the ECC (engine control
computer) but it is much more broadly implemented depending on the model and
manufacturer and may interact with any or every electronic action the car
can do.

 

[Rich Grise]

This is might seem like a weird question. I'm curious how the radio
works in my new car. I have a 2008 Scion. On the steering wheel are
buttons to control the radio: up, down, and mode. Pressing mode merely
allows you to set the audio preferences. The up and down are obvious.
Press up changes the stations. But it only scans through your presets.
It only seeks if you hold down the one of the corresponding keys. This
is kind of annoying. I'd rather it do the exact opposite. When you
press it it immediately seeks to open stations, and if you hold it
down then it'll scan your presets. It's probably possible to change it
somehow. If only I knew how it was implemented.

I called Toyota, and the guy is gonna send me a circuit diagram. But I
still need some ideas. If you have any feel free to shoot them my way.
How would you approach such a problem? How would you figure out how
it's implemented?

I used to fix car stuff. It's a f***ing nightmare. Modifying a car
radio would be even worse.

Let it go. Toss the radio and buy one that operates the way you want
it to, at your local audio accessories store; assuming you can even
get the factory one out of the dash.

Good Luck!
Rich

 

[Sanoski]

Thanks a lot, everyone. It's probably not worth all the effort.
Besides satisfying curiosity, and overcoming a challenge, it really
wouldn't help me with anything. I suppose buying a new radio is an
option. However, if I were to change the stereo, then the steering
wheel buttons wouldn't work at all. That would create a whole new
problem. But I think they have kits for stuff like that. Yea, it's
definitely sounding like more trouble than it's worth.

 

[Newsgroups]

The Scion's radio is set up so you can connect an iPod to it. This is
very nice, as you can select songs from the dashboard and get the
Artist, Album, Song Title on the LCD screen.

However it is very poorly implemented in terms of human interface. I
have >1200 songs in my iPod, and find it very hard to select among them
while driving. You have to take your eyes off the road to read the LCD
display, when trying to select a different Artist or Playlist or Album.
It would have been easy to arrive at a way to use the buttons to
better effect (for example, a button that cycles to the next Album, next
Artist - rather than cramming all selections onto the far right knob.

I do like the volume/song selection buttons on the steering wheel, though.

The Scion's radio is good... but needs some tweaks. I hope they make a
SW upgrade.

 

[pipedown]

All that iPod marketing is getting to me. What about those who do not have
Apple brand music playing devices?

 

[[email protected]]

All that iPod marketing is getting to me. What about those who do not have
Apple brand music playing devices?

Emulation?