Brain Transplant Sunbeam EM6910 - Arduino ESP8266 microcontroller mod
New member, and needing to get my post-count up, so I thought I'd share a project i'm working on. Recently picked up a Sunbeam EM6910 for $10 in great condition, and being a tinkerer, I can't bear the thought of leaving it as-is. Stoked on the OPV and steam flush info I've found on here.
I've got a bit of experience with Arduino-based microcontrollers, and have been playing a lot with the wifi enabled NodeMCU ESP8266 chips. My plan to be able to turn on my machine remotely, or schedule the warm-up is snowballing in to something a little more extensive. The plan is a k-type thermocouple in the espresso thermoblock, and a solid state relay replacing the thermostat, so I can PID control the machine, and fit a digital pressure transducer. with any luck, the only place I'll have to interrupt the factory wiring is up at the control panel, maybe even making it plug and play, so it can be returned to standard. With all this, I'll be able to display to a small LCD and to a web server, the thermoblock temp, espresso pressure, and extraction time.
One day I'd love to replace the brains all together but I need better to understand pump, flow and thermoblock control. Then I could perform automated pressure profiling, just for fun. Once I have full permissions for this forum, I'll add some of my research and design so far. Is anyone else in to microcontrollers and have fiddled with the same ideas? I came across Breville's Naked Espresso, which seemed to be a similar idea, without the WiFi.
Some images of my PCB design etc is over at NodeMCU ESP8266-12E Espresso - Piggybacking factory ICs? - Everything ESP8266
Interesting idea, not a lot of room to work in these machines, you'll have to pack everything in there pretty well.
The thermoblock temperature on these machines are controlled by an NTC thermistor, the thermostats are just there as a safety measure.
Adding an OPV provides little benefit in my experience. I've installed the OPV found on the Breville Dual Boiler to them with not much in the way of shot improvement.
If you can more accurately control the shot temperature, an OPV will probably be of more benefit. The issue the brew thermoblock has is that across the 30-40 seconds of the shot, the water temperature can drop to 85C or less.
I'd probably look at fitting a heat exchanger before the water inlet of the thermoblock to assist. Wrap the piping around the thermoblock before it goes in and it should help.
Thanks for the help mate! I've not heard of people adding heat exchangers, is this a common mod? Is there any good info on it somewhere?
Originally Posted by noidle22
It's been done before on Silvias and other small boiler machines, I've never seen it done on a thermoblock machine before.
Originally Posted by flewis88
The principle is the same though so i think it should work.
Get a length of copper tube the same diameter as the machine currently has and wrap it around the thermoblock.
Terminating the ends with the small compression fittings that Sunbeam use may be tricky, not sure where you can get them or how to install them.
I have some spare EM6910's so i might give it a try sometime as well.
Cool! Let me know how you go!
Originally Posted by noidle22