Building custom parts library


I can not find any proper step to step guide for building custom parts such as relay, sensors etc. Is there any video tutorial which is well described the procedures?

Please let me know.
Note that I tried with Adobe Illustrator to create svg using the layers but didn’t work. I have very little knowledge in inkscape. Please enlighten me.

-Dr. Duaigee Felcon

These two tutorials apply to current Fritzing versions (most of the others are for older fritzing versions)

This Inkscape plugin makes making schematics easier (and is described in my tutorial set)

If you run in to problems post the svg or preferably the .fzpz file of the part that doesn’t work here and one of us will look it over and point out the problems.



You are always the pathfinder where I stuck… man. I will let you know.

I also need another thing to know is creating varient.

Suppose a relay model named “X” has 4 pins and a relay model “X_p” uses 3 pins with all same measurements. I want keep it in varient. Either an user can pick X or X_p from same relay model while he is trying to use it.

I am very good in Eagle cad software though I am using fritzing from the begging of my pcb desiging history. So Here I want to harness every possible things I can learn & help people.

Making this a variant can cause problems. Fritzing will swap the 4 pin version for the 3 pin version which in turn (if there are connections in the sketch) will break, because a connection no longer has a definition in the new part. That said, this will work by leaving the family definition in the fzp properties the same and changing the variant fields between the two parts:

   <property name="variant">variant 1</property>
   <property name="family">Line sensor</property>


   <property name="variant">variant 2</property>
   <property name="family">Line sensor</property>

where the first variant has 3pins and the second 4 pins, will work and swap but as noted will break if the missing pin has a connection (it will cause a red rectangle in the sketch indicating a missing connection definition.)


Using the variant property is the generic method. For the described case, I would probably add a “model” property name to the 2 parts. That will also allow swapping between them. As Peter says, different pin numbers can cause problems when swapping, if the part is already being used in the sketch. When initially placed though, picking the model (or variant) in Inspector to use works just fine.

For additional variations, more properties can be added. For maximum voltage, current rating, or anything else that distinguishes them. Inspector will allow swapping between any that have the same property name and different values. That is the limitation. You can only swap between parts that have the same property. If only one part in the family has a “max_temperature” property, there is no way to swap based on temperature. That does not mean that all of the parts have to have the same properties. If one part has properties A, B, C, and another in the same family has properties, B, C, D, E, then you can swap based on the values of B and C. As long as (one of) the values is different.

@vanepp & @microMerlin for the help