Magic: The Mini-magic Switchboard should I make it a kit?

[wmmullaney]

Oops, missed it thanks so much.

 

[Pommie]

You may need a power switch anyway as you will need the WPUs for the switches. These are around 20k and so can draw a significant current. I guess a simple way around that would be to use 200k pullup/downs on the switches/bulbs.

Mike.

 

[blueroomelectronics]

Well the pullups only matter if the switches are on. Good point though, I'll have to remember to make 1=off

 

[blueroomelectronics]

Dumb question, should I add clamp diodes for the small bulbs? (6.3V 200ma) driven by a 2N2222 transistor.

 

[Leftyretro]

Dumb question, should I add clamp diodes for the small bulbs? (6.3V 200ma) driven by a 2N2222 transistor.

I wouldn't think so as the lamps should not have much inductance.

Lefty

 

[wmmullaney]

Probably not, but since I have so many diodes I might.

 

[Nigel Goodwin]

Probably not, but since I have so many diodes I might.

No need whatsover, there's no inductance worth mentioning, and it's NEVER done for small bulbs like these.

 

[wmmullaney]

Alright then, I won't.

 

[3v0]

Being able to sense if a bulb has been absent is so that you know when a new sequence needs to be inputed. This I believe is a better way than using a timer and probably how the original worked. The only time no bulbs are removed is right at the end of the video and just prior to that the magician does a particular sequence which I assume resets the program (from memory I think it is simply right to left).

Mike.

The timer allows you to reorder the switches without changing any bulbs.
I am adding the sense resistors regardless. It can be built either way.

 

[wmmullaney]

So, Bill, are you going to make it a kit? When done how many $$$ will it be?

 

[3v0]

Magic Switchboard with Bulb Sense Circuits

This is an updated version that includes bulb current sensing. It can be built with bulbs or LEDs. To use bulbs short the 4 SMD jumpers. To use with LEDs install 4 current limiting resistors R10-R13 over the top of the SMD jumpers.

To use bulb sensing install R4-7 and the 4 jumpers shown in RED on the top side of the board.

Install the MCLR jumper that snakes around the chip to the ICSP connector. The route shown here is not a good one. This jumper will not exist in the next rev in that there is a possible route.

EDIT: There are a few things here that are a bit odd. Mostly due to the now quite ready for prime time beta version of Eagle that I am using. But I do not see anything that should keep it from working.

EDIT2: Schematic unchanged. Removed the MCLR jumper and routed it on bottom layer. Decreased Isolate to .032.

EDIT3: Schematic unchanged. Very small change to layout. I am removing the .png for the foil and replacing it with a PFF which is much clearer. There is also text file which is actually a GCODE file to drill the PCB on a CNC machine. You must rename this file to work with you CNC software, maybe .nc or .t
EDIT 4: Schematic unchanged. Board to ver 1C2. Moved processor to make more room for switch connector. Replaced foil.pdf with foil_1C2.pdf.

 

[bananasiong]

CopyLeft3007 3v0
Can I know how do you add the ground traces on the empty space?

Thanks

 

[3v0]

POLYGON GND

If you ground is called GND
The distance between the GND fill and other signals is set by ISOLATE.

 

[bananasiong]

Is this setting done in the schematic before converting it into layout?
I always start directly from the layout and route manually. That's why it takes me very long time for designing the PCB.

 

[3v0]

Is this setting done in the schematic before converting it into layout?
I always start directly from the layout and route manually. That's why it takes me very long time for designing the PCB.

If you start by entering the schematic it will save time. The schematic editor can check the schematic for errors too. If you create a board from a schematic the tool will keep track of where every connection should go and you how many are left.

In the board editor there is a command line box just above the main work area. It is here that you type POLYGON GND. But if you did not create the board from a schematic it can not know which traces belong to GND or any other signal.

Take the time to learn the schemaic editor. It is worth the effort. Help is here if you need it or also on Eagle's email list.

I changed the board to get rid of the MCLR jumper. You may want to look at it.

 

[Pommie]

3v0,

Well done on getting that on a single sided board.

I took the liberty of photoshopping it to clean up the holes, make it black on white and set the resolution for printing. This should now come out the right size by printing in MS Photo Editor. The cleaned up holes also make drilling much easier. With a bit of luck I'll get around to etching one this afternoon.

Mike.

 

[3v0]

3v0,

Well done on getting that on a single sided board.

I took the liberty of photoshopping it to clean up the holes, make it black on white and set the resolution for printing. This should now come out the right size by printing in MS Photo Editor. The cleaned up holes also make drilling much easier. With a bit of luck I'll get around to etching one this afternoon.

Mike.

Laying out PCBs is a lot like doing puzzles. I enjoy it. I kept this on simple to make it easy for others to make. SS and no traces between IC pads.

Looks like you are going to beat me to building it I can not make a board till tomorrow. It is a simple thing. If you have any questions feel free to ask. If you or anyone wants eagle files I would be glad to post them. The quality of the boards printed withing eagle is better.

Enjoy and let me know if/when you find any errors.

 

[3v0]

Foil PDF

The beta version of Eagle has a feature that allows you to create a PDF of the board.
The pdf image is very smooth and clear compared to the exported 300 dpi image I posted.
I am updating the previous set of files to include a PDF for the foil. When I get the top artwork finished I will provide it.

 

[Brian Hoskins]

Neat trick. During the part where he puts all the caps behind his back and asks his friend to pick one, I guess he had to make certain that his friend picked the colour who's bulb was fitted in the 1st position?

Brian

 

[Brian Hoskins]

Ah - sorry about that everyone. First time I've seen this thread and I didn't notice the discussion had gone beyond 1 page! Doh!

Brian