Need to control Hitachi projectors via 15 pin serial
mikeweezer
Posts: 27
Hi Everyone,
I have an interesting project here. I need to contol the standby / on state of projectors based upon the power state of a 110V power (standard) source. Basically, here is what happens:
1. The outlet power is cut
2. I want to plug in a 5V wall wart that will go into an input pin on the stamp.
3. The stamp will see this voltage change and send code to the projector by serial command to put it in standby.
4. When power returns to the outlet, the stamp will sense the 5V change and send code to the projector to put it back in an "ON" state.
Other information:
- The projectors are Hitachi CP-S310W
- Probably going to use ASCII commands over the serial
- othere possible controls are IR and USB port on the projector
Thanks for any help you can offer in advance!
Mike
I have an interesting project here. I need to contol the standby / on state of projectors based upon the power state of a 110V power (standard) source. Basically, here is what happens:
1. The outlet power is cut
2. I want to plug in a 5V wall wart that will go into an input pin on the stamp.
3. The stamp will see this voltage change and send code to the projector by serial command to put it in standby.
4. When power returns to the outlet, the stamp will sense the 5V change and send code to the projector to put it back in an "ON" state.
Other information:
- The projectors are Hitachi CP-S310W
- Probably going to use ASCII commands over the serial
- othere possible controls are IR and USB port on the projector
Thanks for any help you can offer in advance!
Mike
Comments
Be aware that "unregulated" wall-warts can put out lots more than their rated voltage. This should not be a problem with the BS2 (as long as you keep the 'rated' voltage below 12 volts or so) if you put a 22 Kohm resistor in series with the voltage signal. The BS2 has very nice protection diodes that will limit the signal in that case.
The BS2 does serial RS232 really well. You may need a MAX232 level shifter chip.
The BS2 has limited IR support. Most IR signalling is done with a 'burst' of 38 to 40 Khz, of a certain duration and repeated every so often. The actual duration, definition of a '1' and a '0', and the repeats, are specified by the particular IR protocol and vendor. The BS2 can easily put IR 'bursts' with the FREQOUT command, but only with 1 mSec resolution. I think the BS2sx can put out shorter pulses. The Sony protocol requires 0.6 mSec pulses -- you see the problem.
And it is not really possible for a BS2 to act as a 'USB Master', which I assume is what would connect to your projector. In theory, you could use a BS2 to control a PC, which could act as the 'Master', but that's getting very complicated.
Also, I need to put the stamp and components in a nice enclosure so as to not look so cheap. Any suggestions?
Thanks!