[vincentP]

1) I don’t think it’s a sticky vertical slide, but I’ve changed to a somewhat heavier mechanical pencil.

2) I don’t see any loose wires.

3) Maybe a million tiny squiggles, so overheating could be a culprit.

4) Lots of pen lifts. Lots and lots, so not that timeout anyway.

Thanks.
Back to the drawing board….

[vincentP]

I think the motor / servo is OK.

The axidraw was going along fine and raised the pen on its own while continuing to draw.

[vincentP]

Just putting the documents in the home directory works fine.

Thanks

[vincentP]

Thanks

I’ll get to work figuring out what is the best approach.

If just dropping them in my home directory works, that should be easy.

[vincentP]

I’ve started a hackaday project to document this:

https://hackaday.io/project/19861-axidraw-becomes-axipaint

[vincentP]

OK, Axidraw now paints:

https://www.instagram.com/p/BQanC2albTB/?taken-by=vincentpidone

Thanks for the help, Windell.

[vincentP]

I probably would have recognized it as that, if it weren’t a pin rather than a hole, but note that not all of the holes have crosshairs in that drawing (note the 5v holes), so it seemed safer to ask.

[vincentP]

In looking at at http://www.schmalzhaus.com/EBB/EBB/EBB_v23/EBB_v23_brd.pdf the pins for rows B0 through B7 appeared to me to be  unnumbered (see below). Each of those pins labeled as ground have a “+” sign inside the circle, so I figured that I should check to make sure I was looking at /looking for the right thing. 

So, not having pin numbers to go by there, I used “outboard” to mean the ground and signal pins, and not the (“inboard”) 5v pin. Sorry I didn’t come up with a better description.

What was not clear to me was that B0 through B7 number individual pins, and not the row of three pins as a unit.

My confusion on the schematic was that the pins are numbered RB0 through RB7 rather than B0 through B7. I should have picked up on that.

Anyway, I think your last response takes care of my hardware questions.

I’ll try to get the Python changes made over the weekend and test it out.

Thanks for your help.

[vincentP]

OK, I looked at the schematics and board layout, and my best guess is that the 3.3v signal should come across the two outboard pins on B3 (assuming I tell the software to use that).

The numbering system used in those diagrams is not consistent with what is on the board, if I’m reading it correctly.

Also the labeling ground pins with a “+” sign is not a usage I am familiar with.

So, should I look for a 3v signal across the outboard pins of B3 (if I set up the software properly)?

In other words, which is the “signal pin”?

And, if so, which side should be positive? (The relay coil specifies a positive terminal, but I suspect that it shouldn’t really care.) 

Thanks

[vincentP]

I received my 3.3 volt relay today, and mounted it to a board to connect to the EBB.

If I understand your numbering system, B1 is the bottom three pins, B0 above that, then B2, with B3 on the top.

I expect to take 3.3v off of B3, as the connector that I have that fits that pin spacing won’t easily fit the inner connectors.

To check that I had the relay pins correct, I tried to check by hooking it up to B1, since I know B1 works, as the pen lift operates properly.

Not knowing the polarity ahead of time, I metered the pins and was surprised to find +5V center pin to the rearmost pin and -5v from the center pin to the frontmost pin. I was expecting 3v.

If my 3.3v relay will be happy with 5v, then no problem. I figured I should check first. Am I reading this wrong? 

And, assuming I’ll be using B3, which pins should I use to trigger my relay?

[vincentP]

So, truth be told, I don’t know how much current the closed 9v circuit would draw.

I’m assuming it’s not much, as it’s likely just triggering another relay inside the device (I can probably check this).

EDIT: There is no electrical schematic, but they do show a 24vdc solenoid in the parts list. I could pop the cover and see if that’s where the foot pedal goes, but there isn’t another likely candidate for the switch to trigger. 

EDIT #2: The electrical schematic is under the hood (bless them) and calls for a mechanical relay.

If I can figure out how to post a picture, I’ll include that.

From your perspective, speed isn’t an issue: 500ms should be plenty fast enough. I don’t think I need to worry about timing, but could actually adjust your software to compensate, if that turned out to be necessary.

[vincentP]

Well, it’s not exactly your issue, but you probably know the answer:

All I need to accomplish is to close a switch (that carries 9vdc) when a pin on the EBB board goes high, and open it when it goes low. (as discussed above)

That sounds like a job for a relay.

I see stuff about triggering a 5v relay from a 3v signal, but why introduce extra stuff if there is a simple solution?

I, however, don’t see that simple solution. (I don’t need, or want, ten surface mount relays….)

Please point me in the right direction.

Thanks again.

This is the closest thing that I can find:

http://www.jameco.com/z/TQ2-3V-Panasonic-Electromechanical-Relay-Double-Pole-Double-Throw-1A-3-Volt-64-3Ohm-Through-Hole_761563.html

[vincentP]

So, take it off of B0, B2 or B3, while leaving the pen up/down servo on B1?

That sounds fine.

Thanks again.

[vincentP]

Oops, should have read your references before writing my response.

It looks like everything is there.

Thanks

[vincentP]

Thank you very much.

I was thinking that I could simply hijack the output to the servo, but wasn’t sure just what was sent to it.

Replacing pen up/down with pin on/off would be great, if that gets me 3.3v/0v on the pin.

In that case, all I would need to do would be to convert the 3.3v level to 5v.

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