My quest for a cheap LCD for Neato XV!

[jpccusa]

I can smooth each pad, but I do not know how I make sure they are not shorted. Multimeter, or...?

[mfortuna]

Smoothing out the pads will make shorts very easy to find. If you see a short run the iron tip between the pads at it will be removed. A magnifier could help you see any issues.

[jpccusa]

I see. A short, in this case, would be where the solder connected two or more pads. Got it!

[glnc222]

The LCD board cable to the main system board (not the panel cable on the LCD board) is surface mount soldered and lacks a proper strain relief. It can be yanked when opening the case etc. Some sellers would add epoxy over the LCD side as a strain relief for safety.
Also important to unhook the suspension springs before separating top and bottom of the case to avoid accidents.
Many LCD's had to be replaced from damaging the main board cable attachment working on the robots. Very hard to repair without surface mount soldering machines or other special tools and skills.

[jpccusa]

I need to order the Adafruit adapter next, correct?

I just want to make sure that I indeed need to buy the Adafruit board... or can it be wired directly from the unsoldered pads to the new LCD screen?

[glnc222]

As far as I know, a "breakout board" is used to mount something like an IC with pins intended for a PC board, with solder pads provided for other attachments -- when the IC is not going on a ready made board for it, as in prototyping or tempororary, jury rigs. A socket can also be used instead of an IC with through-hole pins, for maximum flexibility. I suppose they could also be used just to organize mating of two cables with multiple lines, instead of an inline connector of some sort.
[edit] As explained later post in this case the board mounts a cable plug socket to facilitate attachment with closely packed lines, similar to IC applications.

[Tris]

I used a breakout board so that I could use a proper 0.5mm pitch ZIF connector for the LCD ribbon.
If you try to solder directly to the LCD's tiny ribbon contacts then you will probably ruin it!

[jpccusa]

I used a breakout board so that I could use a proper 0.5mm pitch ZIF connector for the LCD ribbon.
If you try to solder directly to the LCD's tiny ribbon contacts then you will probably ruin it!

Got it... Breakout board ordered.

Tris, regarding the display showing backwards, is there anything I can do differently or is that the way your hack must work?

[Tris]

If you can't reprogram the LCD to flip the image like Fuzzylogic's method, then the LCD must be physically flipped over.

Unfortunately, that LCD was the only one I could find that would both fit and function in the XV.

[jpccusa]

I got everything that I need to continue. I have a few questions:

1) Do I need to solder each tiny connectors to the corresponding pad in the Adafruit board?
(board looks distorted because the picture was taken through a magnifying glass)

2) Tris, I noticed you cut your Adafruit board. Do you recommend me doing that, and if so, did you use a rotary tool with a cutting wheel?

Thanks again for the walk-through.

[glnc222]

PC board material cuts easily by hand with a hack saw, for fine teeth, and other hand saws with thin blades, coping saw etc. Power tools can be harder to control but each to his own. Commonly cut when using prototyping perfboard.

[Tris]

1. Yes, solder all of the pins, including the two big "anchor" pads at the ends. I hope you have a steady hand!

2. I cut my board down so that it was a better fit in the Neato's case. I used a fine blade hacksaw and then filed off the rough edges.

[jpccusa]

I will try the hacksaw method. Thanks.

I'll definitely need steady hands. Holy smokes!

[jpccusa]

I did it!

Cutting the board was pretty easy like you guys said.



Soldering the tiny connectors was not easy. Many times I thought I ruined it (and maybe I did, time will tell). It does not look professional, but I hope it does the job.


Now for the next step I will need a little more of hand-holding. I need to wire the holes from the Adafruit board straight to the Neato board pads. Can someone correlate the hole numbers in the Adafruit board to the Neato pads using this image that Tris provided?

[jpccusa]

I took a stab at it how I think the wiring would go.

I still can't figure out what connects to the Neato board pads D0 to D7, OSC1, and V1 to V3. Are holes 9 to 16 connected to D0 to D7 in that corresponding order?

[Tris]

Here you go, based on photos and info supplied...

Connect together the following sets of pins on the Adafruit PCB to reduce the number of wires between boards:
1,2,4,6,7,8,9,10,21,22,23,24 >>> GND
3,17,18,19,20,26 >>> VDD
11,12,13,14,15 >>> SDA (use any one of the five SDA pads on the Neato UI board)

In the end you should have 10 wires going from the Neato UI board to the Adafruit board:
VDD, GND, /RES, SDA, SCLK, VOUT, V4, V3, V2, V1

[jpccusa]

Awesome. Thanks again, Tris.

Here is the visual representation of what you said:


I will start making those group connections on the Adafruit board.

The LCD screen is ready (flipped) so it should be fast after these connections are done.

[Tris]

You have made one mistake - the green wire should not connect to "D1 SA1", connect it to either D2, D3, D4, D5 or D6.

BTW, the small hole you have used as pin 1 does connect through to the "square" hole, so use that one to make life easier.

[jpccusa]

This has been one of the most difficult projects I have ever attempted. I underestimated the minute size of all connections. Not even magnifying glasses were enough to show enough detail. I used macro lenses on my iphone, took pictures, then expanded on the phone screen. Over, and over, and over again, until I was satisfied with the job. It took me a whole day to finish, but I did.






(Tris, see here that I used D2 to connect the green wire)

Having said that, I am sad to report that replacing the screen did not solve my problem and I am still getting a blank screen.
Perhaps the /Res connection is causing the problem. I was left with very little pad as I partially destroyed it once lifting the old screen, although I was able to solder the blue wire to it.

[Tris]

The ZIF connector you have used requires the ribbon contacts to be facing upwards, away from the board. The pinouts I gave you take this into account.

Which way up is the ribbon from the LCD plugged into your adapter board?