I was just perusing the Electric Imp GitHub repos, and saw code for Vanessa…and went straight to the reference designs. Nice work Tom! (and everyone else). The place where I work is also a conference center, and we have 16 conference rooms. While we have electronic signage at various places for visitors, each room has a sign, and unfortunately, it is paper, and our facilities manager prints it out every day. I’ve considered setting up monitors, but I couldn’t justify the cost over a single piece of paper.
Vanessa however, might be the perfect solution! Pervasive Displays has a 10.2" epaper display - http://www.pervasivedisplays.com/products/102 that should be large enough to do what I need. Can the reference design handle all of the Pervasive Display screens? If I get the boards printed and built, do I need anything besides the screen and LiPo?
I just ordered 20 boards from SeeedStudio. I’ll likely be willing to sell most of those, though probably just the unbuilt boards. I haven’t put the BOM through DigiKey yet, so I dont know what the components will cost. Looks like a fairly difficult build.
I was just looking at the differences in FPC connectors for the displays. Aside from that, are there any other things that would need to be changed on Vanessa to run the 10.2" displays?
Was just talking to some folks at Pervasive about this - it seems the displays over 2.7" do not have a SPI interface like Vanessa uses; they have a parallel interface instead.
I’ve ordered the 2" and 2.7" displays, and my boards and parts should arrive soon… it will be an interesting build. If you get any more info on the larger displays, let me know.
My boards arrived from SeeedStudio… in TWO WEEKS!. If you haven’t looked at Seeed when ordering boards, especially small quantities, I would encourage you to. You can order as few as 5 boards. I don’t think that this board is hand solderable, so I might be building a reflow oven.
Looks nice. I agree that hand-soldering that would be a challenge, particularly with the fine pitch on the right. I’ve reflowed a few PCBs in a skillet on the stove top, that may be another option if you don’t have a reflow oven handy.
How about a skillet as a board preheater, and then toss them in the oven? I’m sure you want to handle the board as little as possible to avoid moving components. I think I may need to pick up that cheap manual toaster oven at Costco today…My Imped thermocouple temp monitor should work nicely for keep track of things.
If you’re going to reflow them in the oven, I’d do the pre-heat in there too. I just do the whole reflow in the skillet though. 3 minutes on medium to preheat the skillet and board, then high until the solder is all melted, then turn off to let it cool slowly.
I’m a novice at this epaper or e-ink technology. It seems like you build an array and then send it over to the epaper hardware. For a small display it would be OK, but for a large display like 10 inches, would the Imp have enough memory to build the array? It seems like that would be a lot of bytes.
Are you allowed to send the serial data in packets or does it all have to go at one time?
That’s why I like to build the reference designs… I learn loads about the Imp doing so… and lots of other things. I believe the Vanessa uses this for additional memory.
You could practice with bare boards or some other donor assembly. I am not sure if the size of the board matters a lot as I’d guess the thermal time constant of the oven itself is a major factor (guessing, not sure).
Almost certainly full power would be required during ramp to preheat and during ramp to reflow. Also, you have to remove the board from the oven for it to cool fast enough or else keep some kind of fan handy to blow air into the oven with.
ePaper displays and most of the components have arrived from DigiKey… I’m going to take a crack at hand soldering first. I picked up a manual toaster oven at Costco today so hopefully that does the trick. I forgot to order solder paste, so the oven might wait for that. I assume I can load a little solder onto a pad by hand though?
You will probably do really well hand soldering. You can also reflow it after hand soldering if for some reason you need to pretty it up. Loading solder onto a pad will probably work in some ways but I don’t know how one would get the components to stay put. Hopefully you have solder wick, good solder and a good iron. good luck!
So far so good. I started with the GPIO expander, which looked to be one of the harder components, and I think its good to go. I used the drag soldering technique I’ve seen. I ordered HASL boards this time, and having a little solder on the board is REALLY nice. My Ambers were ENIG, and I had to put solder on each pad.
Thanks to all of you who offered reflow advice. I bought a manual Oster convection oven, and I am using it with my thermocouple temp monitor. So far so good. First attempt was to remove an Imp module from a Smartmaker breakout, and then reflowed everything I had hand soldered on my first Vanessa board. Even though I didn’t notice anything during reflow, after cooling and inspection I can see that a few parts that had been slightly crooked are now straight, so I am going to call that a success. As soon as Mouser gets the rest of my components here, we will have Imp - ePaper!
@tom My boards from SeeedStudio don’t have the cutout where the display cable comes through the board. I’m trying to sort out if that is Seeed or just wasn’t in the gerber…
Is that data in the impee-vanessa-slotholes.txt file? They did get the slots for the USB connector…
Took two tries, but I’ve got a working Vanessa! Woohoo! That is not an easy build. And yes, I know… I need to clean the flux residue off a little more.
