Circuit Overlay Modules

idbruceidbruce Posts: 6,134
edited 2020-08-22 - 21:59:23 in General Discussion
Hello Everyone

Let me begin this thread by saying that all input from Parallax is welcome, especially concerning design.

This thread is an offshoot of "Just A Thought Concerning The Circuit Overlay Boards (Product ID: 32999)", which is a thread that I created several months ago, and it can be found here: forums.parallax.com/discussion/171280/just-a-thought-concerning-the-circuit-overlay-boards-product-id-32999. In this thread, I suggested adding a third set of interconnected holes on three sides of the Circuit Overlay Boards (Product ID: 32999), to enable the ability to stack them, and thus making them modular. The Circuit Overlay Boards are compatible with the Propeller Activity Board, the Propeller Board of Education, and the BASIC Stamp Board of Education, which are all good boards for prototyping, as I am sure that most of us know, so modular overlay boards could only enhance their usefulness. In a completely different thread, VonSzarvas recommended the Circuit Overlay Boards to me, after which, I decided to purchase a few, and then told him the following:
@VonSzarvas - Thank you for pointing me in a good direction. If necessary, I can have a board made with the same form factor as the overlay boards. At this point, it is certainly the best way for me to go. SD card ready, wireless programming ready, documentation available, etc... And I can make it look very professional by having a board made with the same form factor as the overlays. No one will know the difference by opening the enclosure, unless they are an EE. It will make my product more expensive, but it will have functionality. :)

Ever since this reply and the forementioned thread, I have been bouncing the idea of creating "custom" overlay boards, with the same form factor as the Parallax Circuit Overlay Boards (Product ID: 32999). Since Parallax has not released the design files for the Circuit Overlay Boards, I took it upon myself to find the exact necessary hole locations for the headers, by digging into the design files of the Propeller Activity Board WX. With these hole locations, I now have the necessary information to create "custom" overlay boards, for the Propeller Activity Board, the Propeller Board of Education, and the BASIC Stamp Board of Education, which would be modular and stackable.

It is my intent to create a template in EAGLE, for making custom overlay boards, which would provide modularity and stackability. When I am finished, I will post the template here. I am not that familiar with DipTrace or KiCad, and it would be nice if someone could create templates for those interfaces. After the templates have been made and posted here, this thread could provide a home for custom overlays, which would be very useful to the Parallax forum community.

My initial intent is to create two custom overlays, one will be for the DS3231N real time clock and the other for the DRV8825 stepper driver. These custom overlays will be based upon popular and proven designs, and when I am finished designing them, having them made, and testing them, I will post them here also. However, I would really love a custom overlay based upon Parallax's RN-42 Bluetooth Module (#30086), but I don't think I could accomplish this task, unless a board house put the components on for me.

When used in a stacking scenario, three sides of a custom overlay will be blocked by the necessary stacking headers, which means that all external connections (servo ports, VIN, LCD, buttons, LEDs, etc) must escape through the fourth side of the board, using ninety degree headers.

The product page for the Circuit Overlay Boards (Product ID: 32999) https://parallax.com/product/32999 states the following dimensions for the product:
Dimensions: 2.2 x 1.5 in

With the header holes being so close to the edges of the board, the pads on one of my layouts was way too cramped, so I checked the dimensions, and according to my measurements, the actual size is 2.2 x 1.54. However this discrepancy could be due to board dimesional tolerances (I wish Parallax would verify this). Whatever the case, I will have to design a custom pad in EAGLE for this template, because the pads from the header library extend off the board (WOW those holes are so close to the edges :) ).

For anyone interested in helping with DipTrace or NiCad templates, or just want to hoard information, I will now provide the pad locations, based upon EAGLE's coordinate layout, which isn't hard to translate into the other interfaces. These pad locations match the pad locations for the header pins of the Propeller Activity Board WX (I also wish Parallax could verify these locations). These locations do not provide any information pertaining to the various breadboards or the outlying interconnects of the Circuit Overlay Boards (Product ID: 32999), they are only for the headers of the Propeller Activity Board, the Propeller Board of Education, and the BASIC Stamp Board of Education. The outlying internconnects for a custom overlay would simply be pads placed 0.10 inches away from the header pads. These pad locations should match the appropriate pad locations on the Circuit Overlay Boards (Product ID: 32999) and I of course, I wish Parallax would verify this :) .
The following pad locations were derived from the Propeller Activity Board
design files and the location of these pads are based upon EAGLE coordinates.

13 Pin Header (3.3V &5.0V)
X=0.285 Y=2.05
X=0.385 Y=2.05
X=0.485 Y=2.05
X=0.585 Y=2.05
X=0.685 Y=2.05
X=0.785 Y=2.05
X=0.885 Y=2.05
X=0.985 Y=2.05
X=1.085 Y=2.05
X=1.185 Y=2.05
X=1.285 Y=2.05
X=1.385 Y=2.05
X=1.485 Y=2.05

16 Pin Header (I/O Pins)
X=0.15 Y=1.85
X=0.15 Y=1.75
X=0.15 Y=1.65
X=0.15 Y=1.55
X=0.15 Y=1.45
X=0.15 Y=1.35
X=0.15 Y=1.25
X=0.15 Y=1.15
X=0.15 Y=1.05
X=0.15 Y=0.95
X=0.15 Y=0.85
X=0.15 Y=0.75
X=0.15 Y=0.65
X=0.15 Y=0.55
X=0.15 Y=0.45
X=0.15 Y=0.35

13 Pin Header (GND, D/A, & A/D)
X=0.285 Y=0.150
X=0.385 Y=0.150
X=0.485 Y=0.150
X=0.585 Y=0.150
X=0.685 Y=0.150
X=0.785 Y=0.150
X=0.885 Y=0.150
X=0.985 Y=0.150
X=1.085 Y=0.150
X=1.185 Y=0.150
X=1.285 Y=0.150
X=1.385 Y=0.150
X=1.485 Y=0.150

All input is welcome :)

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Comments

  • idbruceidbruce Posts: 6,134
    edited 2020-09-06 - 03:26:39
    Reservered for various templates, programs, and libraries.
    _______________________________________________

    Updated 09/01/2020

    Template Package #1: Overlay Templates.zip - This folder contains both a bare bones schematic and board for EAGLE 7.7.0. It is intended to be a starter package for overlay boards, which plug into the headers which surround breadboards, on several Parallax prototyping boards, and they are intended to be stackable. Of course you can alter the size of the board, but the original intended size is 1.595 (in.) X 2.260 (in.).

    Program Package #1: Overlay.zip - This folder contain a Windows program which creates the schematic and board mentioned above, but it allows you to name and store new overlay templates, without a bunch of hassle.

    #This program has been temporaroly deleted.
    _______________________________________________
  • JonnyMacJonnyMac Posts: 6,939
    edited 2020-08-22 - 17:35:25
    I did a PAB overlay for a client that never went anywhere. I did build a few, and they did work, so I know the connector placement is correct. You're welcome to rip this apart and compare it to your own layout.

    I used DipTrace. In case that's not useful I attached a screen shot with critical dimensions/locations.
    1920 x 1040 - 135K
  • Thanks JonnyMac
  • Thanks JonnyMac

    During comparison, I noticed I pasted and posted inaccurate hole locations for the ground header. I will have to update now.
  • Our centers are in perfect agreement and I have updated the hole locations in the first post.
  • That was a HUGE waste of time.... I was trying to model an overlay template according to Parallax's board dimensions. Parallax used DipTrace and I wanted to use EAGLE. The available libraries for pad and header layouts in EAGLE did not allow me to remain within the dimensions. So I fiddled around with creating custom pads and headers.... BLAH BLAH BLAH...... After more than a couple hours into it, I decide to take a second look at the overlay boards and the Propeller Activity Board WX, and see what was the downside of increasing the board dimensions by several thousandths of an inch. My conclusion.... Not a single darn thing!!!!! WOW!!! I feel pretty stupid at this point.

    I am not certain how it will affect other Plug-Ins, but for now, my main target is the Propeller Activity Board WX, so I am going to just increase the template size a wee bit.
  • Alrighty Then....

    As mentioned earlier, the product page for the Circuit Overlay Boards (Product ID: 32999) https://parallax.com/product/32999 states the following dimensions for the product: 2.2 x 1.5 in

    When measured, the actual dimensions are: 2.2 x 1.54

    After adding extra space to the board and unless someone advises me otherwise, the main template and module templates for EAGLE will be: 2.26 X 1.595

    So I have added about 1/32 of an inch to each side of board, which I don't see as a major complication, but I have been wrong maybe once or twice :)

    Additonally, I have come to the conclusion that when I provide module templates, I intend to leave I/O traces unconnected, so that others can choose the I/O pins they want to use, but I will provide instructions and perhaps diagrams of what needs to be connected to I/O pins.
  • idbruceidbruce Posts: 6,134
    edited 2020-08-26 - 13:25:23
    Something else....
    Additonally, I have come to the conclusion that when I provide module templates, I intend to leave I/O traces unconnected, so that others can choose the I/O pins they want to use, but I will provide instructions and perhaps diagrams of what needs to be connected to I/O pins.

    Let me begin by saying that this thread stems from an ongoing project. In that project, I will need to utilize all of the available pins on the Propeller Activity Board WX. I will not be able to utilize all of the options available from every IC and I do not intend to document or provide instructions for these various options. Anything that I provide will be the absolute bare minimum for my needs, unless it is extremely easy for me to do otherwise :)
  • I must say that for the first time, I am truly disappointed with EAGLE CAD. Their pad and header libraries leave a lot to be desired :(
  • Clock LoopClock Loop Posts: 1,900
    edited 2020-08-26 - 17:19:48
    Many pcb/schematic design programs leave much to be desired when it comes to their libraries.

    I just accept that getting good with making your own custom schematic symbols and pcb footprints is inevitable.

    I regularly use the free pcb software at 4pcb.com by advanced circuits, however, you cannot get the gerber files from this program until you make a minimum 4 pcb prototype order with them.


    https://www.4pcb.com/pcb-prototype-2-4-layer-boards-specials.html
    I do the 33 each, 4 pcbs (which is around 150$ shipped, 2 layer with specific pcb restrictions)
    They also have a bare bones option, I have not tried that.

    https://www.4pcb.com/free-pcb-layout-software/

    Their part creation tutorials, and the part creation process and creation of custom user libraries are not that hard.
    Easier than many other programs I have used.

    Just edit a part that already exists in their library, and save it to a new name, along with saving the schematic to a new name and the pcb footprint to a new name, and you can save them all to your own libraries located in your own custom folder for future use/saving. Once you save them all to a new name and your own library, you can edit the schematic, footprint, and save them.
  • idbruceidbruce Posts: 6,134
    edited 2020-08-26 - 18:02:32
    Thanks for the heads up Clock Loop, however I do not have the time or the inclination to learn a different interface. Overall I am quite happy with EAGLE and I have design packages and symbols in the past, but I am talking pads and headers WOW They definitely need better than what they have available. Ever since they were taken over by Autodesk, I thought it would have become much serious software.

    EDIT: I am just ranting and whining :)
  • For PCB layout and schematics I use "Sprint Layout 6.0" from ABACOM out of Germany. Cost is about $70 dollars. Unlimited size and number of holes, etc Super easy to learn. I was designing PCBs in 30 minutes, about the time it took to install and read the introduction and command bar / side bar icons & syntax.

    Decent library and easy-to-design your own Custom parts. It does full Gerber files - multi-layer, solder mask, upper and lower copper and silk screen. Never been disappointed in the results, there may be a few features that Eagle and DipTrace have - but nothing that would be a show stopper.
  • Just looked this one up, and don't see any mention of schematics. Is it a separate program?
  • I’m quite impressed with KICAD. I know you dont want to learn another program, but you are where I was a few months ago, and I’m glad I made the switch. It has made me look far better than I deserve and the library is pretty comprehensive. Basically, if *I* can make decent boards with it, *anyone* can! Lol.

    Since it spits out gerbers, you can shop around. Some of the overseas pcb shops are so cheap as to be nearly free. Example: 5 ea of 100mm by 100mm 2-layer FR4 with ENIG are five bucks. Total. (And then you add $18 for DHL shipping. Oy...)
  • I've been using JLCPCB (Hong Kong) lately -- nice boards, great price, quick delivery.
  • I have been kind of quiet pertaining to this thread, but I am taking it all very seriously. I have spent a lot of time thinking, researching, and toying around with this overlay plan.

    Earlier I stated that I was only intending to complete an overlay for the ICs DS3231SN RTC and the DRV8825 Stepper Driver, but I have decided to also pursue an overlay for the RN42-I/RM Bluetooth Module.

    In my final plan, all three of these overlays will be neatly stacked one on top of the other.

    I am still getting organized and trying to determine my best course of action, but I am working on it :)

    My main conrcern at this point, pertains to powering the Propeller Activity Board WX, because I am trying to avoid the use of multiple power supplies, when combining the Propeller Activity Board WX and the DRV8825 module. The Propeller Activity Board WX Guide states that the board can be supplied 6~24 VDC, although a maximum of 15 VDC is recommended (what kind of nonsense is this). Will it handle the 24 VDC or won't it? :) The DRV8825 design that I am basing the overlay upon, has an input voltage requirement of 8.2~45 VDC. So 24 VDC might be good enough for my needs, if the Propeller Activity Board WX can sustain that input. My plan is to power the Propeller Activity Board WX with 24 VDC and then obtain VIN from one of the servo port headers for supplying power to DRV8825 motor drive circuits of the overlay. The servo port VIN rail of Revision C of the Propeller Activity Board WX should be able to supply somewhere between 1.85 and 3.0 amps, before shutting down, which should be good enough for a decent sized NEMA 17 stepper motor.
  • idbruceidbruce Posts: 6,134
    edited 2020-08-30 - 14:12:50
    I started my post at about 3:00AM and it is now 8:55AM, and I deleted my original content.

    My thoughts at this point are:

    1. Provide a base project for overlays, which people can copy and use to create their own custom overlays, which will go in the second post of this thread.

    2. Begin an Eagle library with parts that I use for creating my own custom overlays, which can and will be ammended to include other useful footprints that may be added by me or others. This library would also be accessible from the second post of this thread.

    3. I have been working all morning long, creating a Windows program called "Overlay". This program takes the base templates of the board and schematic, assigns it a project name, and stores it at a location of the users choosing. Basically it is ready for a user to just type in a project name and select a storing location. This program eliminates copying, pasting, and renaming a blank project, just to get started with an overlay. I will say that it is in BETA state and I will post more about it in the following thread. However, when I have double checked the the measurements, on the board, and perhaps make some improvements for the headers or schematic, I will also post this program in the second post of this thread.

    I will now prepare everything for my next post, which will pertain and contain the BETA program "Overlay".
  • idbruceidbruce Posts: 6,134
    edited 2020-09-05 - 22:22:24
    Please allow me to introduce "Overlay". It is a Windows dialog program which was built and runs on Windows 7, and should be backward and forwards compatible, in case you are running XP or Windows 10.

    Basically the program just creates a fast and easy way to begin a new overlay project. These overlay projects should be compatible with several of Parallax's boards, which contain a breadboard, surrounded by headers. In essence, it creates a bare bones project, having a schematic and a board. The schematic contains six headers, which are (4) thirteen pin headers and (2) sixteen pin headers. The board is designed to be in close proportion to Parallax's overlay board and the headers have all been placed on the board, in their proper locations (but stills needs to be checked for error).

    So without further delay.....

    Here is the main interface...
    overlay.png

    Here is the interface with a project name and a location where the project will be stored...
    project.png

    After pressing the "Create Overlay Project" button, a new folder is created in the selected location...
    my%20overlays.png

    In the project folder, a project schematic and a project board is written...
    project%20folder.png

    Here is a picture of the schematic that was written to the project folder.....
    schematic.png

    And here is a picture of the board that was written to the project folder.....
    board.png

    At this point, parts are ready to be added to the schematic.

    For those that may be interested in testing and looking at the BETA program, I have attached it below.

    #### The program has been temporarily deleted. When uploaded again, it will be in post #2 of this thread.
    1024 x 746 - 49K
    407 x 272 - 7K
    407 x 272 - 7K
    1024 x 746 - 43K
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  • PublisonPublison Posts: 11,661
    edited 2020-08-30 - 15:56:07
    Neat Project Bruce!

    Is the template in metric grid?
  • No I did not, but I can easily add that selection :)
  • idbruceidbruce Posts: 6,134
    edited 2020-08-30 - 15:45:04
    Publison

    What is the benefit of creating a metric template? Isn't it a simple matter of just switching the grid over when you start placing components on the schematic, as well as placing components and putting traces on the board?

    EDIT: Oh I know, snapping to the header pins
    EDIT: On second thought, that should still work
  • idbruceidbruce Posts: 6,134
    edited 2020-08-30 - 15:56:08
    Now I wonder if Parallax used the metric system when designing the Propeller Activity Board WX

    EDIT: However, headers have a 0.10 in. spacing, whereas 2.54 mm seems off the wall :)
  • I will have to put it on my to do list to investigate.
  • idbruce wrote: »
    Publison

    What is the benefit of creating a metric template? Isn't it a simple matter of just switching the grid over when you start placing components on the schematic, as well as placing components and putting traces on the board?

    EDIT: Oh I know, snapping to the header pins
    EDIT: On second thought, that should still work

    If I use .005 grid it snaps to center. Have not used Eagle in a while. I tend to use .025 grid.
  • idbruceidbruce Posts: 6,134
    edited 2020-08-30 - 16:11:43
    BIG "IF" others were to create similar templates, in the varying platforms available, I could add these templates to my program, and then the user could select templates according to the platform they are using :)
  • I sure hope this thread picks up some momentum, because it certainly would be nice to have a hundred or so modules to choose from :)
  • PublisonPublison Posts: 11,661
    edited 2020-08-30 - 20:32:20
    Diptrace board template based on Jon's Diptrace upload. I do not have schematic yet.

    Grids are on .0125"
  • Referring to the Overlay program that was discussed several posts above, today I discovered that I will indeed need to change those headers, because the drc is listing numerous errors. The templates in that program will requiring updating and need to be changed.
  • It has been such a long time since I have messed around with EAGLE. It seems that I have to learn it all again :(
  • I have now altered the headers, added more wire nets, and rechecked the positioning of the headers. New templates have been created and the Overlay program has been updated to include these new templates. Both the new templates and the updated program have been added to post #2 of this thread.
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