I'm working on a project which I have to connect several pins on the parallel port to a NI SensorDAQ. This project requires the device to receive and send digital signal via the parallel port. I have the parallel port wire cutup and am using only some of the pins and have them connect the SensorDAQ via it's Screw terminal connector.
I want to transition from proprietary hardware to the Arduino. My number one concern is: can I fry my Arduino if I connect a parallel port pin between a PC and Arduino's Analog/Digital input pins?
Ifthis is safe, then what's the best way to connect the two; if not, are there any setup I can perform to make the connection?
MorganS:
So long as you have a 5V Arduino, yes you can connect it directly.
Should the input wires (from PC via parallel port) be connected to the digital or the analog input? I also worry about grounding. The UNO has a ground on the digital's side. So I assume that's where I connect the parallel port's ground wire? Would resisters help if I'm really worried about the voltage?
What are the actual voltages that device produces? All that's mentioned in that brochure is a +5V line. If it's a 5V device, then no problem to connect directly to a 5V Arduino.
Resistors may help if you know what voltage the device produces, and if that's higher than the voltage the Arduino can handle, so you know which resistors to use how.
Analog pins A0-A6 are digital pins with analog input capability. Assuming this parallel port produces a regular digital signal, you should read it as digital.
I’m trying to supplant that device with the Arduino, so my new setup will be
PC <— Parallel Port Wires —> Arduino <— some other hardware
Ultimately I’d like the connection to go both ways: the Arduino receive/send signal from and to the PC. Right now, I’d like the Arduino to read signal via the Parallel Port wires (from PC). From your comment I assume the digital ports can handle a 5V input?
“Analog pins A0-A6 are digital pins with analog input capability.”
Does that mean A0-A6 can accept both analog and digital input?
dants:
Should the input wires (from PC via parallel port) be connected to the digital or the analog input? I also worry about grounding. The UNO has a ground on the digital's side. So I assume that's where I connect the parallel port's ground wire? Would resisters help if I'm really worried about the voltage?
Thank you =]
Yes.
Yes. Connect the ground.
Resistors are not necessary for a regular PC parallel port. The standard says it is 5V TTL. For input-only a 1k or 10k resistor between each pin on the PC and each pin on the Arduino will protect against anything short of a lightning strike. But if you are outputting from the Arduino to the PC, a lower value like 1k or less may be required.
That's the point. If it's trying to drive a low-impedance input through a 10K resistor, the low impedance "wins" and just drags around its end of the 10K wherever it wants. Because the Arduino can't drive any more than 5V into its end of the 10K then it can't do much.
I expect however that the PC inputs are high impedance and 10K will work. But I've never experimented with parallel ports myself.
dants:
I’m trying to supplant that device with the Arduino, so my new setup will be
PC <— Parallel Port Wires —> Arduino <— some other hardware
Ultimately I’d like the connection to go both ways: the Arduino receive/send signal from and to the PC. Right now, I’d like the Arduino to read signal via the Parallel Port wires (from PC). From your comment I assume the digital ports can handle a 5V input?
“Analog pins A0-A6 are digital pins with analog input capability.”
Does that mean A0-A6 can accept both analog and digital input?
Thank you
I would really like to see a schematic of how you are wiring to the parallel port pins. Are you sending/receiving the whole 8 data bits? How will the PC program know when to switch from send to receive? Or will there be separate PC programs that do this?
Are you knowledgeable about the timing requirements for the parallel port operation?
MorganS:
That's the point. If it's trying to drive a low-impedance input through a 10K resistor, the low impedance "wins" and just drags around its end of the 10K wherever it wants. Because the Arduino can't drive any more than 5V into its end of the 10K then it can't do much.
I expect however that the PC inputs are high impedance and 10K will work. But I've never experimented with parallel ports myself.
Please excuse my lack of related background =[ . Let me try to summaries your suggestion, and please point out where am I getting this wrong.
So the parallel port outputs a 5V TTL, and because the digital ports on the Arduino can take 5V, no resistor needed from PC to Arduino.
For output from Arduino to PC, a low value (e.g. 1K or less) resistor might be required between the Arduino and the PC?
Paul_KD7HB:
I would really like to see a schematic of how you are wiring to the parallel port pins. Are you sending/receiving the whole 8 data bits? How will the PC program know when to switch from send to receive? Or will there be separate PC programs that do this?
Are you knowledgeable about the timing requirements for the parallel port operation?
Paul
I'm only outputting (from PC) using two data pins, and receiving using three pins. Currently I'm using another proprietary software for managing send and receive. The software is used for presenting Psycho-Neuro behavioral experiments.
I'm not knowledgeable in timing requirements for the parallel port operation. I'm just assuming the software takes care of such thing.
I just took a look at Fritzing for drawing schematics. But it doesn't seem to have any PC components/ports. Do you have any suggestions? I have never drawn a schematic before.
dants:
So the parallel port outputs a 5V TTL, and because the digital ports on the Arduino can take 5V, no resistor needed from PC to Arduino.
When I connected to parallel in the 90's, the data pins drained current. They did not source it but IIRC some control lines did.
It took a while and a long distance call to a EE friend to get that right.
The specifications of the Vernier SensorDAQ are to be found here.
It looks to me as though it is a 'badge engineered' version of a National Instruments product, something like their USB-6008, maybe modified to allow plug in connection of Verniers range of sensors.
dants:
I'm working on a project which I have to connect several pins on the parallel port to a NI SensorDAQ. This project requires the device to receive and send digital signal via the parallel port. I have the parallel port wire cutup and am using only some of the pins and have them connect the SensorDAQ via it's Screw terminal connector.
Someone might have gotten the impression that the Sensor box is currently interfaced to a parallel port.
