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22 October 2011
Author: Giorgos Lazaridis
Tiny LED Debugging Board for Breadboard Prototyping

If you happen to work with microcontrollers or other digital ICs, then you have certainly face a situation where you need urgently 8 LEDs with 8 resistors for a test or other debugging purposes. And it is this time where things get nasty: You are in a hurry because you want to see the results, connecting the LEDs is totally boring, you need also 8 resistors, not to mention the wires, and then, the LEDs themselves are thick and usually won't fit in 8 breadboard rows... You know what i mean.

Therefore, i decided to make a tiny board with SMD LEDs and resistors pre-wired to save the day.

The circuit

The first idea was to make an 8-LED board, because usually data come in 8-bit packets. But since i work with PIC microcontrollers, i do know that PORT pins usually come in sets of 4 pins, excluding PORTB which may come with all the pins in series. Therefore i decided to make boards with 4 LEDs. The idea is that the board will be small enough, so that another board will be able to sit right next to it. This way, both 4-series ports and 8-series pots will be covered. The schematic is ridiculously simple:

The PCB

It was not difficult to design the PCB small enough, since i will be using SMD parts only (excluding the connectors of course). Here is how the PCB looks like:

And here is the EPS file of the PCB:

 PCB EPS file

Then i began the PCB development:The PCB

 I developed 4 PCBs for test. They are very small, tiny! Then i cut them with the saw into 4 pieces With the dremel, i trimmed them to the minimum dimensions possible Two boards must occupy only 8 breadboard columns when placed side by side

Soldering the parts

I will be using size 0805 SMD parts for the resistors and the LEDs. The connectors are simple 0.1' pitch headers:

 Here are 2 boards with all the parts soldered From the top row connectors, i removed the 2 middle pins Goal achieved! Two boards side by side occupy only 8 breadboard columns

Powering the boards

I use 220 ohms resistor for the LEDs. This way, they will normally operate both for 3.3 and 5 volts supply. The maximum current they draw do not exceed the 20mA @ 5 volts, so the PIC will is safe.

These boards are Common Cathode, since all LED cathodes are connected together to the common (Com) connector. A Common Anode board can be made if all LEDs are revered.

 At 22 February 2013, 11:52:45 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]@Fernando Oliveira This one is 0805At 19 February 2013, 17:22:29 user Fernando Oliveira wrote:   [reply @ Fernando Oliveira]Hi, congratulations, great website! Just one question, what is the type of smd encapsulation that you use (1206)? Best Regards, Fernando.At 31 July 2012, 15:16:11 user roja wrote:   [reply @ roja]i appreciate your zeal of going such a work all d best........................At 31 October 2011, 12:01:07 user Johnie wrote:   [reply @ Johnie]Great project, can't wait to try it for myself. Thanks for sharing it with us.At 24 October 2011, 12:09:58 user Kammenos wrote:   [reply @ Kammenos]@cheerio in fact, i'm too lazy myself as well... I made this project because i was asked to by pike :D... But now i made a batch of them, and i will keep some for me...At 23 October 2011, 22:02:00 user cheerio wrote:   [reply @ cheerio]Nice idea. I am always too lazy for setting up smth to "listen" to the controllers. and i always regret it. This is simple and useful.

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