Building an IR Remote Control for Senior Design Project

[frogdogbb]

I am trying to figure out the best way to build an IR remote control. I was going to use momentary switches on the remote and need 18 switches. The remote is going to eventually control a preamplifier I am building for a senior design project which is still a few semsters away. I figure it is never too early to get started. I have know good working schematics that I have built for most of the analog devices I am going to use. The hard thing for me is implementing the LCD display and the remote is going to be tough. I have found a number of encoders/decoders of varing styles but I am unsure what would be the easiest for my application. I would need the following buttons: Volume-up-dn, Treb-up-dn, Bass-up-dn, Tone defeat, Bal--left-right, Low-up-dn, Mid-up-dn, High-up-dn, Mute, Sub-up-dn. I also intend to provide the same switches at the unit for manual adjustment. Each switch or output from the decoder will drive digital pots on the respective boards and output the level to a LCD display. I need some help getting started with the remote first what scheme to use...
Thanks,
Ben K

 

[berkeman]

I believe that there are several IR comm standards that are used for various kinds of remote controls. There is also an audio component comm standard, but I don't know if it extends to IR control of the audio components. Could you please list the various IR comm standards that you are considering, along with their modulation frequencies and other differences?

What are you considering using for the circuitry in your IR remote TX unit? Are you going to use a low power CPLD, or a micropower uC, or some other scheme? There are probably IR TX modules available -- can you use one of those, or are you supposed to build the whole project from scratch? What is your target battery life for the TX remote? Are you going to use a 9V or a couple of AAA batteries? Can you make the keypad switches more complicated in order to extend the battery life? (like using DPST at each switch position, where the 2nd pole is used to turn on the power supply circuit, and the power supply turns itself off after a brief amount of time with no more button pushes...).

 

[frogdogbb]

Those are all good questions, I am not sure what direction I want to go since I am just getting started. There are no design guidelines it is all up to me to pick the project and devlop it. I have found companies like http://www.holtek.com.tw/english/ that make various IC's encoders decoders but I am not sure how to choose what I need...

 

[berkeman]

Since your end application is audio, I would start by researching the comm standards that the high-end audio industry uses. They at least have one for inter-component digital communication, and I'd bet they've adopted some standard for IR remote control too. Once you understand those standards, you can look at what modules are available, and decide if you want to roll your own circuit instead, or leverage off of some existing modules.

 

[dlgoff]

Just a note here. Beckeman said "There are probably IR TX modules available -- can you use one of those, or are you supposed to build the whole project from scratch?", which got me to thinking. Once you are out of school, (at least this is what I've learned since) you don't always have the time or company money to design every detail. And why re-invent the wheel? Integrating existing modules works fine and your job becomes understanding these modules inorder to hook them up together and packaging (making it look cool).

Don

 

[frogdogbb]

There are no restrictions on the project since I have to design lots of other things I would rather the remote be as simple as possible. If I can find a encoder chip and decoder chip that will do what I want that would be great. I even considered the idea of using a universal remote control and a learning decoder to make it work. I found some interesting IC at http://www.linxtechnologies.com/ind...onductor&subcategory=remote-control-ic_series
The problem is the 18 different functions I am thinking I will contact the manufacturer for using these for my application.