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  • Author Author: colporteur
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KiCAD 6.0 symbol development question

colporteur

I am moving from generating PCB layouts using Fritzing to KiCAD. It has been something I have been considering for a while. I have been investing some resources (time, money and energy) in learning KiCAD 6. I have just completed the module on constructing your own symbols. This has some appeal to me, I've done some research on the topic and would like to get feedback from member that have some experience with KiCAD.

Here is the scenario. I have recently started using a DR21A01 relay module. I would like to have a symbol to call the module in KiCAD. My first thought is someone must have already done this. It doesn't seem realistic that individuals using KiCAD are constructing a symbol for this module when they need it.

image

The site I purchased the units from has a schematic of the modules. None of the KiCAD symbols sites I have visited has a symbol for such a module. What am I missing? Are my expectation to high? Maybe a reputable site provides the resources to support the product. I tend to buy in markets that have the cheapest price. That doesn't necessarily mean you get all the things you need.  

I'm thinking components like this should have CAD modules that can be incorporated into designs. Yes/No?

Since I have limited experience with KiCAD I hoped those in our E14 community would share their knowledge. I did a search for an IR sensor modules I use often. Again nothing supported in a CAD. Maybe I am looking in the wrong place.

Do all KiCAD users just bang out their own. Seems rather labour intensive.

Chime in with your thoughts. I'm eager to learn.

  • in reply to colporteur

    It might be a very popular module for prototyping on stripboard/perfboard/breadboard, where the 0.1" pitch is useful.

    For a PCB project, there are popular relay footprints already in KiCad, and a transistor and diode and resistor is easily added.

    This relay for example: 5V DPDT Relay is $2.38 so more expensive than the module, but there are similar footprint (datasheet) alternative relays are also available from Aliexpress, which are cheaper than the module by far; this is about $2 for five of them, so $0.40 each:

    image

    The transistor, diode and resistor will be very cheap too.

    In KiCad, the symbol and footprint for G5V-2 matches these relays (many relays will match that footprint, it's fairly standard). There are already single and split symbols for it in KiCad. 

    By doing this, you'll save costs for the PCB version of the project, rather than using the module. Granted you lose the ability to easily unplug the module, but you might be able to find turned-pin sockets that accept the relay (might need the holes widened in the footprint to insert the sockets however). It might be more reliable too, since the relay module is only tethered from one side.

    image

  • in reply to colporteur

    Application defaults and default design rules are different things.

    The ONLY application default I suggest you change is the `N` hotkey. It cycles the grid setting. While very useful in PCB, it creates a lot of problems in Schematic. Since the `M` hotkey (for move) is very popular, it is simply too easy to accidentally hit `N` and not realize it.

    In Schematic, Preferences -> Preferences -> Hotkeys -> filter with "Grid" -> right-click on "Switch to Next Grid" -> select "Unassign Hotkey."

    As for Design Rules, it is a different story. In PCB, File -> Board Setup -> Design Rules is where you configure for the PCB fab you're using.

    In constraints, you'll want to set the minimum clearance and minimum track width to whatever minimum your vendor uses (4mil, 6mil, etc.) The rest of the defaults in this window is generally suitable for most of the popular prototyping houses.

    In Net Classes, you'll want to set the Clearance and Track Width to something slightly larger than the minimums. For example, if the PCB fab has a 4mil clearance and 4 mil trace spec, then I set the Default Net Class to 6mil and 6mil. That way I have assured some margin. (And if I need to go smaller, then I create a new net class and assign those specific nets to it.)

    You should always set your Net Class rules before routing anything. But, if you already started designing the PCB after editing the Net Classes, go to Edit -> Edit Track and Via Properties, select the "Set to net class values" radio button, then click OK.

  • in reply to shabaz

    (can't edit)
    I've placed a bit of info regarding the split symbols at this KiCad 6 blog post (in the section titled Creating Multi-Element Symbols).