The precision and craftsmanship in fabricating this replica machine is astounding and fascinating. There is a Canadian guitar builder near Toronto who replicates the original Gibson electric guitars of the 1950's to the degree that it is difficult to distinguish them from the originals. There must be something in the water up there.

It's cold most of the year and people get bored indoors.
Plenty of great craftsmanship on all sides of the border, the Monolith grinders for instance are a testament to that.
Agree, bidoowee is doing fantastic work.

Lol. The water and boredom - my prime motivators.

They say that the reason that the coffee in Naples is so good is "l'acqua" - the water. They also say the same for the pizza. It would be nice to have whatever they've got in their water around here - though it may have something to do with that volcano (which I personally can do without).

Ok, I've been lax with the my posts and a few weeks have gone by. However, even though we are experiencing our brief period of non-inclement weather we refer to as 'summer', I have not been entirely idle.



I ordered a bunch of electronic parts for the controller box.



Including these LEDs from Bivar, which came in a fancy box and are somehow suggestive of marriage proposals.



(With this LED, I thee wed?)



I've not done enough PCB design work to be confident enough to order a board without building a prototype first. Normally I would just test the circuit on bread board, but this one has to handle AC distribution, so I decided to put one together on proto-board. After a lot of faffing around in Eagle CAD (candidate for the world's most un-intuitive CAD package) and time spent dragging the net for 3D models of the components, I settled on an enclosure size and cut the blank board to size.



A first go at the layout of the lower and upper levels. AC-DC supply, 5V relay and opto-isolator board.



The Arduino fits over the top.



And the LCD and keypad shield sit on top.



The models of the keypad shield PCB that I found on the internet don't quite match the one that I have. This meant that I spent a looooong time measuring the layout with calipers to figure out where the holes have to be cut in the enclosure box. This will be easier next time as I will design my own shield.

Four hours of setup for two minutes of cutting? Too late now if I got this wrong!







Thankfully, it fits.



The button hole cut-outs are a little on the large size. I think that the CAD model I used must be incorrect.
Still, more than good enough for the prototype.

Very impressive and humorous update.

Thx arcus. But remember, only Canadians are allowed to make fun of our summer!

@Paulo - That is correct, no sight glass in this machine as I believe them to be unnecessary. I did post a quick write-up of the auto-fill circuit a while ago. I'm just finishing up the wiring of the controller box which deals with auto-fill, PID, AC distribution and Interface. It should be done early next week.

Canada is a great place: trees, more trees, beer that doesn't taste like water, Montreal. We even have a puppy for prime minister. Getting things to Canada from the US on the other hand, is like chewing pebbles. I've been waiting since the end of July for paint samples to come by USPS. Lost in the mail. Resent. Still waiting.

In the interim, I've been in a grim death-struggle with Eagle CAD, candidate for "World's Most Un-intuitive CAD Package".
I also wired up the prototype controller. All the AC and signals to the lower board (the bull-dog clips are holding a piece of rubber over the exposed AC connections on the bottom) :



Then I made a break-out for the IO to the micro-controller from a piece of protoboard and some jumper wires. It plugs into un-used analog pins on the Arduino.





Overall it's a bit messy, but not too bad given that it is frankensteined together from various different projects. The only real problem is that the USB port is at the opposite end from all of the other connections. This is inconvenient for positioning the box in the base of the frame. The other mild annoyance is that the LCD screen is just too wide to fit across the short side of the box. So, at least for now, the interface will have to read from the side of the machine.

The next step is to make custom boards for the keypad/screen and the power distribution/sensors/relays because protoboard just ain't gonna cut it. Ultimately, it would be better to incorporate all three boards into a single one, but that is a lengthy task which requires a much higher volume to make it worthwhile. Here is a first bash at the keypad shield.



This is a pretty simple board: just the connections between the LCD and the microcontroller to make, plus an IDC connector to hook up a few flavors of power, ground and a bunch of pins to the lower board. The keypad design is clever - all the buttons are on a single analog pin, pressing one of them engages one of five different resistors. The pin reads the resistance and thus can distinguish which button has been pressed.



There is, however, a mistake in the original design which has been blindly duplicated hundreds of thousands of times. The transistor that controls the LCD back-light is missing a diode (or minimally a resistor) to prevent current flowing back to the IO pin on the microcontroller and burning it out.



Suffice it to say that this shall be remedied.

bidoowee wrote:In the interim, I've been in a grim death-struggle with Eagle CAD, candidate for "World's Most Un-intuitive CAD Package".

Interesting, I've been using Eagle for many years, and while it's far from perfect, I certainly would never consider it that. A question, if you're using SMD resistors, why through hole switches? Just seems like once you've chosen any SMD, it's silly to use any more than the absolute minimum through hole parts.

bidoowee wrote:There is, however, a mistake in the original design which has been blindly duplicated hundreds of thousands of times. The transistor that controls the LCD back-light is missing a diode (or minimally a resistor) to prevent current flowing back to the IO pin on the microcontroller and burning it out.

I wonder if the original design had a FET there and the Chinese copies just replaced it with a transistor to save money?

Ira

Ha - (at the risk of going mildly off topic) I suppose there are worse programs out there, but this is a commercial product and I expect better. Just on example: performing an action on a group requires first choosing the group tool, making a selection, changing tools, then right clicking(!?) to execute the command on the group! Why is there even a group "tool". And, unlike all other CAD packages I've ever used, there is no way to permanently define and name a group. I won't even begin a rant on the library management and search.

Yes, SMD throughout would be more efficient, but the LCD is an off-the-shelf through-hole and all of the pin headers are for breakout that will (very likely) not be used. As this is a beta, I am also only making a handful of these for now and, because I don't have a re-flow oven, I can't install parts if the pads are inaccessible. So that narrows my choice of switch. Through-hole are also cheaper - I found them at 10 cents on the dollar from a supplier that isn't digikey or mouser. This is not an interface that is going to see anything close to constant use, so 5 million cycle quality is not required.

The transistor error is well documented on the forums. It is in original schematic and was quickly fixed by dfRobot when it was pointed out to them. There are an awful lot of clones of the first design still out there though - I received mine a couple of months ago. The FET would be the way to go, but chucking in a resistor is a lot cheaper if you aren't concerned with quiescent current draw (guess which way they fixed it ).