Components on opposite side of the ErgoDox PCB

[snowe]

What do I need to do if I need to put the components (Teensy, I/O Expander, etc) on the opposite side of the pcb. I want to make a switch plate that doesn't have cutouts for each of the components, and I still want the usb port to be on the right hand side. Will I just need to modify the firmware or is it even possible at all?

[jacobolus]

Should work okay. You probably have to either reverse all the diodes or else swap the rows/columns in your firmware though. Also, the USB cable is pretty much stuck on the side with the teensy.

[snowe]

Ok so keeping the Teensy on the right side is possible, but I might need to reverse a ton of stuff. I just really don't want to mess this up, though that's not likely. I knew that the usb was stuck on the side with the teensy, I just wanted to make sure to keep the teensy on the right side, while still getting a plate on top.

[jacobolus]

No, I think if you want it on the back the teensy will have to go on the left side. (Or you can probably use patch wires to get the right teensy pins connected to the right holes if you want, instead of soldering it directly to the switch PCB.)

Before you try this, you’ll want to make sure you understand how the circuit works, and make sure you know which trace goes where.

[vivalarevolución]

I want to do the same thing and I plan to just buy all the electronic components for the Ergodox and take it from there.  Make it easy on my self.

[Grendel]

What do I need to do if I need to put the components (Teensy, I/O Expander, etc) on the opposite side of the pcb. I want to make a switch plate that doesn't have cutouts for each of the components, and I still want the usb port to be on the right hand side. Will I just need to modify the firmware or is it even possible at all?

Just load all the components as per instructions except the switches and diodes, then flip the boards (swaps left and right) and load the switches on the backside. Load the diodes on the component side or use through-hole diodes in the switches. This will mirror the key layout, so you will have to compensate for this in the firmware.

[snowe]

What do I need to do if I need to put the components (Teensy, I/O Expander, etc) on the opposite side of the pcb. I want to make a switch plate that doesn't have cutouts for each of the components, and I still want the usb port to be on the right hand side. Will I just need to modify the firmware or is it even possible at all?

Just load all the components as per instructions except the switches and diodes, then flip the boards (swaps left and right) and load the switches on the backside. Load the diodes on the component side or use through-hole diodes in the switches. This will mirror the key layout, so you will have to compensate for this in the firmware.

I know I can do that, but that will switch the usb to the left side. I would prefer to keep it right side. If it's not possible that's fine, but I would prefer it that way.

[Grendel]

Not possible since the USB connector is not reversible. You would have to keep it on the side the switches are on if you keep the Teensy on the right hand.

[jacobolus]

As I said, if you want you could just glue the Teensy onto the underside of the PCB and use little patch wires to connect the proper pins with the proper holes. Pretty annoying and hacky though.

Why does it matter so much that the USB cable is on the right side?

[MOZ]

The only issue with mounting the components to the bottom side is the USB port, if you want to keep it on the right, you might have to let go off the micro-USB all together and hardwire a cable.

[Grendel]

Tru dat. You could  leave out the USB connector and connect the USB cable directly to the Teensy. Be aware that in the original schematic the Teensy 5V pin is not connected to the PCB 5V trace (the PCB gets its 5V from the separate USB connector), you will have to add a patch-wire to make that connection. Else the other half of the ErgoDox will not get power. The boards from mechanicalkeyboards.com have this fixed, the boards from massdrop don't (IIRC.)

[snowe]

Not possible since the USB connector is not reversible. You would have to keep it on the side the switches are on if you keep the Teensy on the right hand.

Hmm. I'm a little confused by what you mean. Why is the usb connector not reversible? Can't I just switch the ID and D- wires and the 5v and Ground wires (respectively)? Or are are there more connectors that I'm not seeing here? (I don't have the electronics yet, they got delivered to the wrong address, but I do have everything except those and the cables)

As I said, if you want you could just glue the Teensy onto the underside of the PCB and use little patch wires to connect the proper pins with the proper holes. Pretty annoying and hacky though.

Why does it matter so much that the USB cable is on the right side?

I like it for the aesthetic. All of my cables on my desk go to the right, so I think I would prefer it. And I'm custom building a case so I'm pretty dedicated to the looks so far.

The only issue with mounting the components to the bottom side is the USB port, if you want to keep it on the right, you might have to let go off the micro-USB all together and hardwire a cable.

What are the exact issues with mounting the mini-USB on the bottom? I'm looking at the pcb and it looks like I should be able to switch certain wires coming from the teensy and going into the usb plated through holes. I'm also referring to this image

Tru dat. You could  leave out the USB connector and connect the USB cable directly to the Teensy. Be aware that in the original schematic the Teensy 5V pin is not connected to the PCB 5V trace (the PCB gets its 5V from the separate USB connector), you will have to add a patch-wire to make that connection. Else the other half of the ErgoDox will not get power. The boards from mechanicalkeyboards.com have this fixed, the boards from massdrop don't (IIRC.)

I got the PCBs from MK, and upon inspection the trace from the 5V annular ring for the USB section is going to the VCC ring on the Teensy section. I am starting to see why this won't work, mostly because of the power thing. So if I flipped the Teensy to the opposite side the VCC ring would be laid out with the Ground ring and that's not going to work is it?  Though it doesn't look like the ground from the Teensy is going anywhere. Why is that?

If I don't flip the Teensy, but instead leave it in the same orientation but place it on the bottom so all the ports still align it should work though. Are there any cons to that?

[jacobolus]

If I don't flip the Teensy, but instead leave it in the same orientation but place it on the bottom so all the ports still align it should work though. Are there any cons to that?

I think that should work. Though the USB connector might get in the way. Try it out and let us know how it goes.

[Melvang]

I do want to add one thing.  You do have to use the pads on the PCB for the USB wires to connect the Teensy.  I don't remember what the reason is but if you just try and plug directly into the teensy the keyboard won't work.  At least thats what I recall.  I could be wrong on this though but I really don't think so.

[Grendel]

Not possible since the USB connector is not reversible. You would have to keep it on the side the switches are on if you keep the Teensy on the right hand.

Hmm. I'm a little confused by what you mean. Why is the usb connector not reversible? Can't I just switch the ID and D- wires and the 5v and Ground wires (respectively)? Or are are there more connectors that I'm not seeing here? (I don't have the electronics yet, they got delivered to the wrong address, but I do have everything except those and the cables)

The reason is that the 5V,  GND and ID pins not only connect to the pads where the wires gets soldered in but also the the PCB GND plane and 5V trace. If you solder the connector to the "wrong" side of the PCB, 5V will be applied to the GND plane (and thus 5V to the ID pin) and GND to the 5V trace. Bad things will happen... W/o cutting traces and adding patch wires, the USB connector has to be on the top of the PCB if the Teensy is on the right hand and on the bottom of the PCB if the Teensy is on the left hand.

I got the PCBs from MK, [..]Though it doesn't look like the ground from the Teensy is going anywhere. Why is that?

It's connected to the GND plane on the other side Just checked, on these boards the 5V problem is indeed fixed.

If I don't flip the Teensy, but instead leave it in the same orientation but place it on the bottom so all the ports still align it should work though. Are there any cons to that?

Only that you can't access the reset switch anymore. But the reset pad is exposed, you can easily bridge GND and RESET w/ a metal object like a screwdriver. Also mind the clearance of the USB connector, if you solder the Teensy too close to the PCB you can't insert a regular USB mini cable anymore (USB plugs shell needs 2mm or so additional clearance from the board.)

[snowe]

Thanks jacobolus, it looks like I'll need to leave clearance for the usb connector anyway, but the standoffs should be just long enough to do so.

The reason is that the 5V,  GND and ID pins not only connect to the pads where the wires gets soldered in but also the the PCB GND plane and 5V trace. If you solder the connector to the "wrong" side of the PCB, 5V will be applied to the GND plane (and thus 5V to the ID pin) and GND to the 5V trace. Bad things will happen... W/o cutting traces and adding patch wires, the USB connector has to be on the top of the PCB if the Teensy is on the right hand and on the bottom of the PCB if the Teensy is on the left hand.

It's connected to the GND plane on the other side Just checked, on these boards the 5V problem is indeed fixed.

Only that you can't access the reset switch anymore. But the reset pad is exposed, you can easily bridge GND and RESET w/ a metal object like a screwdriver. Also mind the clearance of the USB connector, if you solder the Teensy too close to the PCB you can't insert a regular USB mini cable anymore (USB plugs shell needs 2mm or so additional clearance from the board.)

Ahh I thought that these pins:

More

weren't to be soldered to the female usb plug, but they are. Wish I had the rest of the electronics to be able to see this stuff. I'm probably asking questions too early. I'm just excited to get this started.

I did not realize that the GND was connected to the entire board. After looking at the schematic and PCB I see it now.

And I should be able to access the switch from the side, there's a good several millimeters of space to insert something flat to hit the switch. Which pad is the reset pad? I don't see it on the schematic and there are like 8 pads on the back of the teensy and I can't find the schematic for it. And thank you for the heads up on the clearance for the usb cable. I don't think I would have thought about that before soldering.

I do want to add one thing.  You do have to use the pads on the PCB for the USB wires to connect the Teensy.  I don't remember what the reason is but if you just try and plug directly into the teensy the keyboard won't work.  At least thats what I recall.  I could be wrong on this though but I really don't think so.

I'm looking and trying to figure out why that would be. I found this on the Deskthority wiki http://deskthority.net/wiki/ErgoDox#Electronics

The USB cable could also be routed directly to the Teensy 2.0. On early revisions of the PCB (Massdrop), an additional wire would also have to be connected from Teensy pin VCC to the pad marked "5V" near the plug's position. The latest revision of the PCB would not require an additional wire.

if that is what you are talking about then I should be good, because I can see that the 5v trace does make it to the Teensy. At least I'm hoping so. I can test with a multimeter.

Thanks for all the help guys! This is such a great community. I can't wait to get the electronics so I can actually begin putting the Dox together.

[Grendel]

Which pad is the reset pad? I don't see it on the schematic and there are like 8 pads on the back of the teensy and I can't find the schematic for it.

Look at the backside of the Teensy, short edge -- it's labeled RST

[snowe]

Ah I thought you  meant a flat pad, not a through hole.