Radio events (how?)

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.

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

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.

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.

Sanoski wrote:

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

Emulation?