So I’ve been busy doing a bunch of computer maintenance and looking into other things I’ve neglected while building the roaster so it’s been a bit slow. I decided I wanted to start gluing corners together and drilling some holes to see how the case goes together so I can eventually get back to fixing the issues with the roast controller case. Over the past several weeks I soldered together all of the boards, made wiring harnesses and figured out a bunch of “oops” moves I had made designing things when I got rushed for time.
Turns out I was not able to get stand offs locally in the sizes I had wanted so the heights are all screwed up where I placed holes on the outside surfaces. I also forgot to specifically allocate power for the exhaust fan in the original design BUT I did have “Spare” pins allocated. The fan I ordered also was not the right size for the hole template I had used (Inside fan dimension vs outside screw / case dimension)… neither of them were actually labeled right the way every other fan I have is sized.
So with everything screwed or harnessed in place this is what I have for the Arduino…
The Arduino wired for Coffee Roaster control
It is a MEGA2560 mounted on a Crib for Arduino. On top is an Ethernet Shield w/ microSD slot. Then I used a variety of crimped headers to connect to some of the pins on the MEGA and on the ethernet shield. I have twenty five lines in the bundle going to the Arduino. I had some spare 10 strand cables from a project at Halloween and no 25 strand cables to use so I used one of those cable wraps to keep the all together after connecting DB25 to one end and header pins to the other. Once the lid for the crib for Arduino is in place it then connects to the back of the enclosure.
Wiring Harness connecting to the back of the controller enclosure
As you may notice the sockets I was using for connecting the power out are the type that snap in. The majority of these will not snap into most laser cut plastic sheets and instead are designed for aluminum cases. The plug to the right on the other hand screws in. These work great with a variety of thicker locations. The fan was originally going to be on the inside with a wire cover on the outside but with the wrong size fan hole in use I had the wrong cover to fit the fans that I had that would fit the hole.
For the DB25 connectors it turned out good that I had decided to use a cut out pattern that had the holes on the side for the anchoring hex nuts rather than just having them cut out so that I could mount them to the socket and anchor the connector. Since the stand offs were too short they don’t allow me to anchor the PCBs to the bottom plate. Instead I had to screw them to the back plate using normal screws and with the burnt circles on the laser cut work I had to use some washers too to keep it sturdy. This is what the back plate looks like.
Rear Panel of controller
This panel includes – One non-filtered switched 15Amp Power Entry module, 2 snap in 15 amp convenience plugs, 1 5VDC fan, 2 DB-25. The left one is the main guts for the LCD, TRIAC control, potentiometers, thermocouple, and a variety of other sensors. The right includes all the non-essential stuff for backlighting all the buttons on the button pad and a few other things including spare wiring. You cna see just a screw on the right since it was relatively intact and so it won’t block the DB25 plug being used. The right DB25 has washers and screws in place. These are primarily used to attached the PCB in place attached to the back side.
Next up is the inside view of the electronics area:
Rear View of the Back Panel
Rear view of the back panel. I need to shrink up the crimp connectors around the wire (they shrink like heat shrink tubing but is actually much firmer). Also the connector on the right side (the switched power entry module) should have the screws more securely fastened with nuts and washers but this is mainly just a test to ensure it all fits together and then allow me to focus on some programming for a while to see if I can get more working and develop menus etc. The clear acrylic bar is used to anchor the corners better. I need to change the locations of the screws since I could not find screws the size I wanted without spending way too much for large quantities of them on the internet and having them shipped to me etc. The thermocouple board on the right had the same issue with the stand offs so it is just floating loose in there right now. I need to find somewhere to get the Omron thermocouple sockets where I dont need to order them by the 1000s since it looks like Ryan McLaughlin has stopped selling things on his site when they (used to) have problems getting the newer MAXIM thermocouple chip. They’re all over the place now but he hasn’t restarted his store up so I don’t know the deal there.
Here is the view down into the enclosure from above:
Top view into enclosure
With the cover on:
Front panel installed on enclosure
Front panel running
Front Panel Running
When I send it back out again for a new case I hope to have a different board to install that will be switching the smaller breakout boards being designed onto the circuit board as well as add a power supply and possibly having an arduino board mated on top of the circuit board perhaps to bring more of the electronics inside. I might want to try to get a Digilent board perhaps to try converting to it as a transition between Arduino and PIC32 before I completely switch to a dedicated PIC32.
I’ve also been looking at possibly creating a dedicated PC application to communicate with it directly via USB and over ethernet. I am toying around with the “QT/QML” language but havent gotten too far with it. I may just go back to Processing though.