Author: Quinn Dunki

Juice Bridge

August 13, 2011

Getting magic smoke into your breadboard with style.

 

I have a basic low-end benchtop supply. It does the job just fine, but is a little light on features. I decided to put together a little bridge between my bench supply and my breadboard that would make development just a little bit nicer. I call it the Juice Bridge.

Here’s the feature set that I wanted in the Juice Bridge:

  • Quick on/off switch for the board, separate from the bench supply
  • Indicator light for when the breadboard is hot
  • Switchable between unregulated supply and regulated 5V
  • A place to patch in an ammeter for measuring the draw of the entire circuit
  • A bunch of reference ground pins for scopes, meters, etc
  • Supply to both sides of the breadboard

Pretty simple, right? Here’s the final product, in all its “glory”.

Here’s the schematic:

...

 

You can also download the eagle schematic file, for a better look.

I wanted this to be something I can use reliably for a long time, so I etched a PCB for it using this process. My layout in Eagle looks like this:

 

Here’s the eagle PCB file if you want to etch your own.

 

Using the aforementioned process, I etched the PCB:

 

From there, it’s just drill, solder, and test!  Here’s the final result.

Here we can see all the major features. On the left is the power LED. It has a jumper above it which can be removed (to disable the LED) when accurate current measurements for the circuit are needed. Above that are four general-purpose ground pins. Above the ground pins is a jumper block which can be removed, and an ammeter can be patched in here. Next to the ammeter jumper is a switch which selects full power from the bench supply, or regulated 5V. The twisted pair going into the board is from the bench supply. The big rocker switch is the quick-access power toggle for the breadboard. It's a light-touch switch, and is placed in the most physically stable area of the board for quick power cycling.

 

There are legs in the back, to keep it stable while connected to a breadboard.

That’s all there is to this little guy. Do you have suggestions for improvements? What features would you add or change? Let me hear about it in the comments!

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