I currently have two homemade Arduino based BrewPis set up and love how they are doing at controlling my fermentation chambers. For my setup, I really have no real need to change away from the Arduino based BrewPi - they work great, and I have no expectations to be in any position for any kind of automated brewing for a very long time (if ever). However, the one way that the Photon would be a benefit for my setup is the Wifi (Assuming it can use WiFi to communicate back to a machine elsewhere on the network for logging and control in the same way the Raspberry Pi currently communicates with the Arduino and I assume the Photon via USB). This would allow me to have just a photon at each chamber, and run the control and logging on one or more Virtual Machines, rather than on Raspberry Pis (Not that there’s anything WRONG with the RPi).
Is there any technical reason a person would not be able to use a Photon with a generic breakout shield like the ones Particle sells on their site (Or even use a breadboard and power it via USB for testing) and break the appropriate pins out for relay control and OneWire?
A few notes if you want to roll your own:
We used a OneWire bus master for reliable OneWire communication. The photon is 3.3V, you will need a level shifter for reliable OneWire communication I think. Or at least a pull-up resistor to 5V. Then you will also need to take care of the timing. The bus master handles most of that for you.
We used high quality connectors to make it easy to connect things in a reliable way. This is mostly what makes our controller expensive. Yes, it will cost more than wires on a breadboard, but 99% of the problems with OneWire that I had to debug were related to wires.
You won’t have a display
You won’t have a buzzer
We CE tested our boards for emission AND immunity and added a few solutions to the board to make it more reliable in harsh conditions.
You won’t be ready for future expansion boards that communicate over RS-485.
We don’t want to invest time into make our code compile with your DIY boards. We have higher priority items on our list, you are on your own in this. If you buy an official board, we’ll guarantee it works.
You won’t be supporting our development. Yes, I charge more for the boards then the cost of components. That profit allows me to work full time on this and to invest in further development.
P.S. If your fridges are close together, we are working on running multiple fridge from a single BrewPi spark.
Thanks Elco. Don’t get me wrong, the BrewPi Spark is a very nice unit and although I haven’t seen one in person, from all appearances, it looks to be of top notch quality. However, some of us need to be more ‘frugal’ than others. Unfortunately, at this point in time, I have to brew on a shoestring budget. I have less into three self rolled Arduino based BrewPis AND my two fermentation chambers than the cost of one Spark, mostly because I already had the main components laying around from other projects, and my fermentation chambers were craigslist finds that I fixed. Given what I’m doing, I really have no need for more than what the Arduino based version is capable of doing. The WiFi in the Photon would be nice, but it’s not a requirement. If I had any aspirations towards automated brewing at any point in the reasonably near future, then we’d be talking a different story. At this point in time, I only need to control fermentation temperature, and as my two chambers are at opposite ends of the house, at this time, I need two separate controllers, regardless.
I understand what you’re saying about the high quality connectors and the troubleshooting you’ve had to do in the past. You’ve told me a few times about that. To be fair, I can no more comment on other peoples abilities than you can on mine, but my guess is the vast majority of people that had issues probably knew FAR more about brewing than electricity/electronics - I personally know PLENTY of home brewers that fall squarely in that category and aren’t ashamed to admit it. I’m the opposite - I know more about electronics than brewing (Although I won’t claim to be an expert). Where I fall woefully short is with programming. That’s where you lose me. But wiring pretty much anything isn’t an issue. Both of my BrewPi’s have been rock solid as built with the stock 0.2.10 firmware. I was only talking about a breadboard for testing a homemade Spark. If I was going to do it and put into real use, I’d either get a shield to plug it into or design a PCB for it (granted, any PCB I were to design and have made wouldn’t be as good as the one in the spark by far - I’ve only designed and had 2-layer PCBs made).
The question was mostly a ‘is it possible’ question. If it was feasible, much in the same way an Arduino based one can be made using stock firmware without the official shield, I probably would have attempted it. Based on your response, it seems the OneWire could make it not really possible, as I’d assume the firmware is looking for that Bus Master, so if it’s not there, it likely won’t work right (if at all). As such, I don’t think it’s something I will try to tackle. If the time ever comes that I do move into automated brewing, or if I end up with ‘disposable income’, I’ll very likely end up ordering a Spark (or whatever is current at that time).
If you really want WiFi, but stick with the arduino, you could use a photon as a WiFi proxy. Here’s the steps in outline:
- get a photon from Particle.
- write an application that bridges Serial1 with a TCP Server, so any data read over serial1 gets sent to all connected TCP clients, and any data read over TCP gets sent over Serial1.
- modify the brewpi arduino firmware to communicate over Serial1 rather than Serial
- connect the Arduino TX/RX pins to the Photon’s RX/TX pins.
NB: Brewpi doesn’t yet support WiFi, which requires changes to the python script. When WiFi is supported, this system would allow you to wifi-enable an arduino setup by adding a photon.
Note that this means you’re still using the Arduino version of brewpi, but have the added benefit of WiFi with the photon. With the Photon being only $20 it’s not a huge outlay, and then you also have the photon for when you’re ready to later update to the Brewpi Spark shield.
I have a Brewpi Spark but I thought about reconstructing the shield, too (To have a second one which could stay at my brewing station). A time ago I found Elcos published circuit diagrams on the particle forums (click me) and for me it seems to be possible to reconstruct the shield.
I really understand that you don’t want to waste time on supporting DIY boards (Software development is much more important!). But it is possible for everyone who knows what he is doing to reconstruct the shield with this circuit diagram?