This is the instructable for the Espresso for Geeks project.
The hardware mods being installed here are:
- high power SSR for boiler
- AC interface circuit (zero-detect circuit, SSR for pump, SSR for solenoid)
- pressure transducer
- high precision digital thermostats
- digital flow-meter
- front panel (128x32 LCD, toggle power switch and navigation joystick)
- stock steam wand replacement by Rancilio Silvia v3 wand
Step 1: Circuits and Enclosures
Once you have received your 3 boards (front panel, AC interface, micro-controller), solder all the parts as per the schematics and PCBs found here.
Then mount them on the 3D printed parts found [here].
To mount the boards on the support structure, use screws/bolts on each corner or simply glue get on top. As for the front panel, it should be glued on the right side and fastened via the toggle button bolts on the left side.
Step 2: Unplug/remove All Wires
Remove the top metal/plastic panel by unscrewing the 2 screws. This should expose the interior as per the first picture. Next step is to remove all the wires (this can be done by hand) and put them on the side. You will need to loosen the screw that sits on top of the boiler to remove the fuse from under it. You should now have something that looks like that second picture.
Step 3: Remove Front Buttons
The next step is to get rid of that black buttons enclosure on the front side. There are 2 metal brackets on each side of the enclosure that will need to be pushed in until the buttons enclosure can be slipped out the front opening.
Step 4: Unscrew Thermostats
Next step is to unscrew and remove the 2 thermostats that can be found on the side and top of the boiler. Be warned these have white thermal paste on them, which is super messy and manages to get itself on EVERYTHING. eeww.
Step 5: OPV Adjustement
Now it is time to adjust the OPV. Remove the tube and then unscrew the top of the OPV. Then you will need to use an allen key to tighten the OPV (screw down). By default, the OPV is set to approximately 12 bars, but with this mod, we don't need the OPV anymore, so we need to screw it firmer until it goes to over 15 bars so that it never evacuates water anymore (the maximum the pump can push is 15 bars).
Step 6: Remove the Steam Wand
Now we can get rid of that low quality steam wand since we will be replacing it with a Rancilio Silvia v3. Just unscrew it from the boiler and put it aside.
Step 7: Install the Flowmeter
Now it's time to install that flowmeter.
The flowmeter will sit between the pump and the water tank. Notice it has an arrow on it to indicate the flow - you want it from the tank to the pump.
Start by drilling 2 holes (around 3mm) as per the picture (the distance between them is exactly 12 mm, you can see the datasheet).
Then cut the silicon tube that runs from the pump (under it) and the water tank and simply insert the flowmeter between them, then insert it into the 2 holes you just drilled.
Step 8: High Power SSR Installation
Now we want to install our high power boiler SSR. This component can be mounted on the metal enclosure directly, with some thermal paste between it and the enclosure to make use of the enclosure as a heat sink.
So, first step is to drill a couple of holes, then thermal paste on the SSR, and then bolt it on as per the pictures. Easy :)
Step 9: Front Panel
It's now time to install the front panel PCB + plastic cover on the front of the machine.
The first step is to install the PCB. The PCB is designed to fit nicely into the bezel of the rectangular opening. It is therefore possible to use the 4 holes on the corners to screw the PCB into 2 pieces of wood or plastic that are located on the other side of the enclosure, therefore setting the PCB into place nicely.
Once that is done, you can glue the plastic enclosure on top of the PCB.
Finally, the toggle button can be inserted from the inside out and the bolt screwed into (no need to tighten too much!)
Step 10: Install Pressure Transducer
Cut off around 1 inch of the PTFE tube (4mm internal diameter, 6mm external diameter) that connects the pump to the OPV.
Insert a "push-and-connect" type T fitting between the pump and the OPV.
Start by assembling the pressure transducer so it attaches to a "push-and-connect" fitting.
Insert the 1 inch tube into the end of the assembly.
Attach the whole assembly into the T fitting.
You have no inserted a pressure transducer between the pump and and OPV which will measure the pressure of the water being pushed into the brewhead!
Step 11: Make and Install Thermostats
Create 2 thermostat assemblies as per the instructions here.
Step 12: Install New Steam Wand
Now it's time to install the new steam wand - follow these instructions. You will need to find a 1/8 to 3/8 male to male brass fitting adapter that is wide enough on the 3/8th side to fit the spring. I couldn't find one myself so I instead I found a smaller spring than the one that comes with the wand. You might want to bend the brass pipe that connects the steam valve to the hose to position the wand to your liking.
Step 13: Wire Up!
It's now time to wire up every as per the schematics. I won't go into the details here but you can look at the example pictures. Once you are done, you can glue the plastic support onto the side of the metal enclosure (or you can glue it before wiring everything up!).