Charlieplexed lighthouse version 2 PCBs have arrived

A long exposure makes it look quite funky

My version two charlieplexed lighthouse circuit PCBs (charliediscs) have arrived back from the Seeedstudio’s fab. I used the same deal as for my last boards, this time it took around 3 weeks in total.  That’s pretty good for 20USD!

The overall circuit is the same as the prototype I built two years ago but with some improvements to make it easier to use and also to allow you to use normal LEDs rather than surface mount packages. It’s mostly SMD but I’m still using the DIP package PIC12f683 (datasheet) as I have a whole bunch of them that I bought a while ago.

 

Two of the new boards. Seeedstudio sent me twelve in total.

Top side of the board. Note the hybrid LED pads that combine the SMD with a plated hole for normal LEDs. I also added a couple of mounting holes.

Bottom of the board. It's mostly the LM317 voltage regulator down here. If you were using a regulated supply you could by-pass it.

The board is designed to suit many type of LED package. Here's are some standard 603, 805 and 1206 packages (top) and a couple of oddballs (bottom)

 

You could also use some fancier packages such as these PLCC packages or the OSRAM PLCC side LED that I used on the prototype (top and bottom)

 

But for this one I'm going to use some super-bright 5mm blue LEDs that I've had kicking around for a while. I've bent them at a right angle so the light goes sideways.

Make sure you fit the LEDs with the polarity running in the same direction. It's doesn't really matter which way you choose as long as they are all the same.

All the LEDs are soldered in, just need to clip the legs.

By swapping around some of the pins this version can be programmed and then run with the ICSP connector still attached. No need to have the isolation switch that I needed on the prototype. It makes testing much easier.

Schematic for version 2. More or less the same as v1 but now the ICSP Clock line is used as the button input rather than as part of the charlieplexing. This means it can be programmed without needing to isolate the ICSP lines.

The original prototype (left) and the new v2 circuit (right). The new circuit is a bit bigger, partly to fit the hybrid LED pads in but also because the max size for the PCB deal was 5cm x 5cm so I thought I'd make the most of it. Note the red dip switch serving as the ICSP isolator for programming the prototype. We don't need that any more!

Another arty long exposure shot.

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