 | | RE: Custom Firmware, IR Problems, and Dead RCXs (long)
|
| Hi all, Just a couple a quick comments on this thread - I'm a firmware design engineer who's done lots of work with IrDA. I don't, however, have any experience with the internals of the RCX or the IR Tower, other than owning them and reading this (...) (23 years ago, 27-May-01, to lugnet.robotics)
| | | | | RE: Custom Firmware, IR Problems, and Dead RCXs (long)
|
| (...) You are right, but the RCX and the tower are right at the hairy edge. The additional 50R impedance will leave the near mode essentially unchanged and I'll sacrifice on the high range. Start with the tower. If you use a 9V battery, the IR (...) (23 years ago, 28-May-01, to lugnet.robotics)
| | | | | RE: Custom Firmware, IR Problems, and Dead RCXs
|
| Ralph, Thank you for painting a much clearer picture of the internal design of the IR Tower. I agree with your observations, but have a question: Is the processor in the IR Tower controllable (i.e. downloadable, like the RCX)? If it is, then there's (...) (23 years ago, 28-May-01, to lugnet.robotics)
| | | | | Re: Custom Firmware, IR Problems, and Dead RCXs (long)
|
| (...) For what it's worth, it's not actually that bad. I don't know the specs on the NPN transistor, but I suspect 1.14A would kill it almost instantaneously. One important factor you've left out of this equation is the 9V battery itself. We often (...) (23 years ago, 29-May-01, to lugnet.robotics)
| | | | | Re: Custom Firmware, IR Problems, and Dead RCXs
|
| (...) Actually, it's the computer itself that determines the duty cycle. This does mean that you could change the duty cycle, but you should be aware that it would be at the expense of noise immunity and would require a higher sampling rate from the (...) (23 years ago, 29-May-01, to lugnet.robotics)
| | | | | RE: Custom Firmware, IR Problems, and Dead RCXs
|
| (...) Ummm, that doesn't make sense. You know where the midpoint is by knowing the baud rate, and hence the bit width. The only time you need to sample at the beginning of the bit time is to look for a start bit. This is all very basic asynchronous (...) (23 years ago, 29-May-01, to lugnet.robotics)
| | | | | RE: Custom Firmware, IR Problems, and Dead RCXs
|
| (...) <snip> (...) <snipped more> Well, no. The RCX receiver is a standard IR unit tuned to the carrier frequency. when I look a the signal on my scope, I get a nice square-shaped wave that is the same as the data byte (with start and stop bits) (...) (23 years ago, 29-May-01, to lugnet.robotics)
| | | | | Re: Custom Firmware, IR Problems, and Dead RCXs
|
| (...) Gee, could you tell I don't have a block diagram of the innards of the RCX? 95% of the work I've done with microcontrollers has been based on the MC68HC705J1A, J2A and K1 series (mainly because that's what I have the development tools for). (...) (23 years ago, 30-May-01, to lugnet.robotics)
| |
