Background:

When hackaday announced the circuit sculpture challenge in august I was very excited. I was already impressed by Mohit Bhoite's sculptures on hackaday and his interview on embedded.fm (ep 314) really encouraged me to give it a try. So what better excuses than a hackaday contest.

Never having made a sculpture before I thought it be wise to do a basic tutorial for one first (the link in the embedded.fm shownotes was very helpful). Trying things for the first time not being challenging enough I thought it would be fun to try this as a date.

On this date we learned the following:

  • Cutting mats are not heat resistant
  • You will need up to 4 hands to complete some connections
  • Double sided tape is not ideal.
  • SMD LEDs like to stick to soldering iron tips
  • Soldering is a fun date activity

Most circuit sculpture tutorials recommend holding parts in place with double sided tape. However the heat of the soldering iron will reduce the stickiness of the tape (to not sticky at all anymore). So the need for a solder-able hold in place method was born.

I like to hobby a lot with soft robotics projects which (for me) are made of silicone. Because silicone is quite heat resistant I came to mind for a jig. When you pour silicone you will almost always have a little left which pools at the bottom of your mixing cup. When it sets eventually it forms a nice round complementary solder pad. Trying to make one of the other designs in from the Instructable on my own worked quite well.

Since you can shape silicone in many ways when you actually pour it in a mold (instead of leaving it in the cup) the idea of making a pattern to hold the brass rods in place started to form. Later the realization came that the air pumps I was using for my soft robotics project could be used to create a suction to keep SMD components in place.

Leading to the project page we are on now. I had a complicated idea for a circuit sculpture in mind for the contest however working on the jig itself became quite interesting and challenging. I also hope that by making this project page I can receive some input from other circuit sculpture builders. Mainly about what parts are often used and difficult to work with without a jig, also for which orientations solder support is appreciated. Plus feedback on the OpenSCAD is also appreciated. I am really curious what people think about the variable naming scheme, since I personally am really fond of it.

OpenSCAD file

Naming scheme for variables is based on parts of a city. Code is now on Github, though it still needs development in order to produce a useful jig.

Variable names above ground
Variable names underground

Keep in mind that the current physical build is far from perfect. The 3D model code is also quite inefficient since it takes both a long time to render as well as to preview. The concept of this jig is great, however there is a lot to improve before it's ready help anyone. But I believe the soft soldering jig can help with circuit sculptures.

to do

  • Make list of components to support
  • Vacuum pump control by foot pedal
  • design multi angle layout
  • figure out how to support parts in Z plane
  • optimize OpenSCAD code
  • Maybe design some manhole covers (plugs to block airflow)

challenges to keep in mind

  • Monitor how silicone reacts to the heat of repeated soldering
  • Calculate airflow requirements
  • OpenSCAD render times are getting too long
  • Keep in mind what you actually want to do with this project page.
    • Keep it somewhat concise.

Silicone used and heat resistance rating:

The silicone used is of shore A15 which is permanently heat resistant to 200C and short term heat resistant to 300C. While these is "high" temperatures soldering is usually done at 350-400C so our application is outside of the specs of the silicone used. There are types of silicone which are more heat resistant they are also higher shore rating (A45 -A60) which makes them unusable. Fortunately silicone does not meld or evaporate when its overheated, it mainly...

Read more »