Physical Layout for Solderless Projects
Here's how to perform physical layout using RTM's free Layout app. Visualize your Project before ordering parts. Know layout details and even build steps in advance.
The Physical Layout Problem
Without exception, every builder runs into the same new-project barrier. Where to position items in a physical container space?
To jump this hurdle, we need a components floor plan that shows;
- The size of the container Platform or Chassis
- Size and location of major components
- Access for Input, Output and Power
- Implied Wire-Routing thru remaining space
Without a plan, we might make costly mistakes and waste time. With it, we can move forward with confidence.
Free Layout Software
I needed layout plans for projects on this website. Drawing them by hand would be a pain. I ended up writing a free Windows application called RTM_Layout. Its easy to learn and use. Registered users can grab a copy and be crafting decent layouts within an hour!
An overview of the software is found on this page.
Let's Perform Physical Layout
Using RTM_Layout, our first step is estimate container size. The application defaults to 10 by 8 inch. You can change size any time.
Next we add rectangular 'Blocks' to represent major components such as; Breadboards, MCU boards, Power Supplies, etc. In RTM_Layout, Blocks have preset dimensions and perhaps an image.
There's also a Blank Block that can represent any component. Set Blank Block dimensions to correct real-world size. If you don't know the dimensions, use calipers. You might also find that info online or perhaps ask at RTM Forums.
With all major components added, you can play what-if. Move them around your container space. Try different arrangements. You might even save arrangements with different file names. Eventually, you run into the next hurdle...
How to Recognize a Proper Layout
How can you tell if your current layout is any good? Here's some suggestions to check against your design;
- Got room for needed components? If not, resize your Platform.
- Are Input-Signals close to Output-Signals? Keep apart as best you can.
- Are noise-sensitive Analog wires routed near noisy Digital wires? Keep well separated!
- Are wire routing distances for Signals too long? Make short as possible!
- Is there adequate space for needed wire paths? If not, consider rearrangement or resizing Platform (see previous bullet item).
- Are Temperature sensitive devices near Heat generating ones? Keep far apart as possible!
Visualize Signals in used Circuit Space
RTM_Layout provides an optional feature especially for Solderless projects. It can display allocated Breadboard circuit-space containing Bus Signals such as; I2C, SPI, Digital, Analog, Power and more.
This helps you visualize used Breadboard real estate before committing to a layout! The same facility shows Signal connections needed on Breadboards and other Components such as MCU boards.
Connections (perhaps I should say Connectors) show as Blank colored rectangles. Allocated areas show as dashed-line colored rectangles with Signal ID text. This helps you identify areas for connectors VS. areas allocated for Breadboard circuitry. See next image...
When you move or rotate any Block, Signal areas and connectors follow accordingly. Its easy to see the resulting impact on wire routing!
The next image is an RTM_Layout Snapshot. It shows Signal allocated-areas and connectors. I annotated a bit to indicate wire routes. Note how short these routes are.
You are not required to use or set up Signals. Its there if you need it.
Visualize Build Steps
Okay, our Layout is looking pretty good. But another consideration is Build-Order. What components mount to the Platform first, second and so on? Assembling in the wrong order may result in trashing one or more components!
For example, Runtime Micro's Experimenter Project cements Ground-Plane sheets first. Next, Barrier Strips are attached with screws. Now its easy to line up Breadboards (using temporary spacers) to cement each an equal distance from its neighbor Barrier strip.
Doing those steps out of order would be a problem. Obviously, I can't cement Breadboards and then cement Ground-Planes. And I can't do the spacer trick to accurately position Breadboards unless Barriers are already mounted.
Well, RTM_Layout makes it easy to visualize these Build Order steps. It displays your Layout as it will appear after each completed step. All that's required is assign a Build-Order value (1 thru 9) for each Component. Then you can quickly dial-up Build-Order views (using menu or Function keys). Those views would appear similar to the following animation.
However, you are not required to use or set up Build-Order properties. Its there if you need it.
Documenting your Project
A hard copy of your Layout Diagram could bolster project documentation. RTM_Layout print size is based on Zoom. At 100%, it prints very close to actual size. At smaller Zooms, printouts can be cut and pasted in a notebook.
Another RTM_Layout feature is Snapshots. Use these jpeg files in WP documents or Web pages. All Layout Diagram images used at Runtime Micro we're created by RTM_Layout (several on this page).
Finally, RTM_Layout provides a simple parts-list type Report. Send to printer or export to Excel, PDF, Word.
We've seen how physical layout diagrams help to;
- determine adequate container Platform or Chassis size
- choose Component arrangements with short Signal routes
- avoid or minimize Noise and Temperature problems
- ensure there's enough Breadboard real-estate for Signals and circuitry
- visualize the overall project including Bus Signals and external connections
- visualize a step-by-step Build Order
- add to Project Documentation
Have fun imagining your next Project using RTM_Layout. You'll find it on the DOWNLOAD section of this website.