Circuit Overlay Modules
idbruce
Posts: 6,197
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:
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:
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 .
All input is welcome
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
Comments
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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.
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I used DipTrace. In case that's not useful I attached a screen shot with critical dimensions/locations.
During comparison, I noticed I pasted and posted inaccurate hole locations for the ground header. I will have to update now.
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.
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.
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 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.
EDIT: I am just ranting and whining
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.
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...)
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?
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".
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...
Here is the interface with a project name and a location where the project will be stored...
After pressing the "Create Overlay Project" button, a new folder is created in the selected location...
In the project folder, a project schematic and a project board is written...
Here is a picture of the schematic that was written to the project folder.....
And here is a picture of the board that was written to the project folder.....
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.
Is the template in metric grid?
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
EDIT: However, headers have a 0.10 in. spacing, whereas 2.54 mm seems off the wall
If I use .005 grid it snaps to center. Have not used Eagle in a while. I tend to use .025 grid.
Grids are on .0125"