Help: Arduino controlling slide projector

Hello. I'm need to control a Hasselblad PCP80 slide projector with arduino. I wan't to use a 6 pin DIN connector on the projector (for remote-control)

It shouldn't be a complicated task I think, but I don't know much about electronics, so can someone please guide me in the right direction. What components would i need... and so on.

Thanks...

Click-clunk. A real slide projector - fantastic!

Richards suggestion of reed relays is ideal because they only draw 15mA so they can be driven directly from an Arduino output. However I would put a diode across the coils to snub any voltage spikes from the inductive load. The end of the diode with a stripe goes to the Arduino output and the other end to ground with one end of the coil. Almost any diode will do, something like an 1N4001 would be fine.

Also, any other ‘ordinary’ relay is likely to require a transistor to drive it without overloading the output.

I agree that small low coil current 5vdc relays are a nice solution. First however you need to determine if the command pins on that connector pinout need to be switched to ground pin or to the +24vdc pin to activate. I think the easy way to test is to just power up the projector with nothing plugged into that connector. Then carefully measure for voltage on one of the command pins with the other meter lead on the ground pin. If you measure a voltage, then connecting the command pin to ground with a switch or relay contact is the method to activate the command (note the limit on how long to activate the command), if you measure 0 volts between the ground pin and a command pin then momentary connection from the command pin to the +24vdc pin is the way to activate the command.

Lefty

Your correct RC, I missed that. However my method would have worked. :D

Thanks a lot, that is very helpful.

Will this relay do the job?

http://elektronik-lavpris.dk/product_info.php?products_id=88810

this relay has an integrated diode. Does that mean i don't need to put a diode across the coils? ( as Si suggested)

Thanks

Nija: Thanks a lot, that is very helpful.

Will this relay do the job?

http://elektronik-lavpris.dk/product_info.php?products_id=88810

this relay has an integrated diode. Does that mean i don't need to put a diode across the coils? ( as Si suggested)

Thanks

Then you don't need an external diode, however when there are internal diodes across the coil you must connect the coil terminals with the proper voltage polarity or the internal diode will short out your power source when switched on.

Lefty

Great

Yes a bit expensive... but I will only need a few. And this one can be driven directly from an Arduino output too?

Thanks

Thanks again your help is much appreciated!

Another question: There is another control connection on the projector

I would like to be able to turn the lamp on/off, but I have no idea what this pulse stuff means? Any idea how to control the lamp with the arduino?

Don't worry I won't hold you responsible for anything :-)

Yes but the instructions says lamp off: pulse + 11-20 V so it probably wouldn't be a good idea to connect it to the 24V pin...

It probably will turn it off, but maybe it will stay this way forever :-)

It's quite an expensive projector, so I guess I'd better not mess with this then.