Wireless Brewpi Via Wifi

thekraken · Aug 31, 2015

Rather than make a definitive how to guide I wanted to start sort of a discussion/development thread on getting the brewpi's arduino wirelessly connected to the pi (or linux machine) via a wifi adapter. I'm specifically referring to the new(ish) and popular esp8266.

This assumes that your are familiar with wiring up uControllers. Don't forget that the esp8266 needs a steady 3.3v power supply with 500 - 800 milliamps (if I remember correctly), and your 5v+ power supply to your arduino will fry your esp8266. I'll leave wiring diagrams and circuits for another post. I suggest looking into the LD1117 voltage regulator.

A few months ago I had the chance to play around with this and had a mostly working prototype.

The first thing I had to do was acquire an esp8266 module. These modules come several different variants. While any variant will work (I think), a variant with GPIO12 broken out is very convenient in that you can hook it up for wirelessly reprogramming the arduino. I chose to use variant esp-03. Variant esp-01 already has header pins on the breakout board and if you are not worried about wirelessly reprogramming the arduino this may be the easiest variant to get up and running. I assume that most people aren't re-flashing their arduinos after initial setup anyway.

The next thing to do is find some firmware that will allow the esp8266 to act as a "transparent serial bridge". In other words, all it does is act as a wireless serial communication relay sending and receiving serial data over your wifi network. There are a few different projects out there, I chose to go with the esp-link project as it had the wireless flashing feature mentioned in the last paragraph.

If you used the esp-link firmware and followed the setup instructions from it's project page you should be able to access your esp from an ip address like http://192.168.1.70 for example, and to access it as a serial relay you would go to port 23 (http://192.168.1.70:23). I believe that the firmware has since been updated to give the esp a host name so you can name your esp to something link esp-brewpi and access it like http://esp-brewpi:23, refer to the github project for more info.

After you've confirmed that your esp is up and running and connected to your network you need to setup the brewpi scripts on the raspberry pi (or what ever your server is) to access the arduino via wifi instead of serial.
To do this you will need to adjust a couple lines of code in the brewpi scripts. The first thing is to change the line in BrewPiUtil.py:

Code:

ser = serial.Serial(port, baudrate=baud_rate, timeout=time_out)

to

Code:

ser = serial.serial_for_url(port, baudrate=baud_rate, timeout=time_out)

That will be around line # 130.

And the second is to change the port variable in the config.cfg file from this:

Code:

port = /dev/ttyACM0

To something like this (this depends on your setup):

Code:

port = 192.168.1.70:23

After you make those adjustments and reset your brewpi scripts it should be good to go.

At this point I had some issues with periodically dropping the wireless connection but I think it had more to do with a poor power supply to my esp8266.

For those of you wanting to try to use the esp8266 with your brewpi setup I hope the above information will be helpful in at least steering you in the right direction.

esp8266 variants: http://www.esp8266.com/wiki/doku.php?id=esp8266-module-family
esp-link: https://github.com/jeelabs/esp-link
brewpi-script/BrewPiUtil.py: https://github.com/BrewPi/brewpi-script/blob/21caa7a408a7fe0ede08b544c8768b9d8c902d7d/BrewPiUtil.py
brewpi-script/config.cfg: https://github.com/BrewPi/brewpi-script/blob/015e5c7040672af9e0dc3045ac1b681036c372d6/settings/config.cfg.example

doomy86 · Oct 5, 2015

Thats great work thekraken, thank you.

I wonder how difficult it would be to adapt the brewpi code to run entirely on the ESP8266. Mabe with a small I2C OLED display.

dibbz · Oct 13, 2015

Thanks for this, it motivated me to give it a go.

I needed to add socket:// to get it to work.
ie.
port = socket://192.168.1.70:23

I can start it up and it gets the version but I can't discover devices, really don't get much past that, I am using an esp-01 and getting a lot of packet loss just idle to esp-link, which I think is the issue. Might try a esp-12.

thekraken · Oct 13, 2015

How are you powering the esp? Also, have you had the esp up and running reliably before for any other project? If you can't get passed the version check that's not very useful.

dibbz · Oct 13, 2015

I have a 12v 1a power supply feeding both the arduino and a voltage regulator for the esp. I was using a $1 ebay adjustible unit but I replaced that with a ld33v regulator & caps with no difference.

ESP appears fine otherwise.

I get the feeling the pings are just the esp and a bit of a red herring. If I do them every second I get a lot more packet loss than every 5 seconds.

root@brewpi-test:~# for i in $(seq 1 10); do ping -c 30 10.69.69.26 | grep "packet loss"; done
30 packets transmitted, 22 received, 26% packet loss, time 29037ms
30 packets transmitted, 22 received, 26% packet loss, time 29075ms
30 packets transmitted, 27 received, 10% packet loss, time 29042ms

root@brewpi-test:~# for i in $(seq 1 10); do ping -i 5 -c 30 10.69.69.26 | grep "packet loss"; done
30 packets transmitted, 30 received, 0% packet loss, time 145159ms
30 packets transmitted, 30 received, 0% packet loss, time 145153ms
30 packets transmitted, 30 received, 0% packet loss, time 145166ms
30 packets transmitted, 29 received, 3% packet loss, time 145153ms

If I telnet to the port, it will work for a few commands then stop responding, brings me back to the packet loss. Might try another ESP to be sure.

Do you have any issues around esp-link dumping the last 1k of buffer when you connect? I can see how this is nice for a console but it feels a bit loose if you want true serial over IP behaviour.

Cheers!

thekraken · Oct 13, 2015

I can tell by your terminal command skills that your probably better at this than I am. I hadn't run a packet test like that, I can't imagine that when I was up and running that I was losing that many packets. Also, in other projects, iv run telnet sessions with the esp-link for several hours without a hitch. I'm sorry that I'm not in a position at the moment to run those command along with you.

What's the physical separation from your WiFi router like?

thekraken · Oct 13, 2015

doomy86 said:
Thats great work thekraken, thank you.

I wonder how difficult it would be to adapt the brewpi code to run entirely on the ESP8266. Mabe with a small I2C OLED display.

I don't know. truthfully, I hadn't even written my own firmware for an esp. Iv just been using them as a cheap way to make my arduino projects wireless. Off the top of my head I think you would be limited by too few gpio pins.

day_trippr · Oct 13, 2015

Not to minimize the effort to port the BrewPi AVR code to ESP8266, but on the hardware side all you really need for a bare-minimum BrewPi minion is one pin for the One-Wire "bus" for the probes, and two pins for relays - and one more if you're switching a fan...

Cheers!

dibbz · Oct 14, 2015

1. The esp8266 was roached, luckily another arrived from China

no packet loss.
2. the serial.inWaiting() appears to not work with socket://, I'm no python expert. The subroutine that gets the version uses serial.readline() and works.

So with this in mind, in addition with the config change;
BrewPiUtil.py ~ line 129
- ser = serial.Serial(port, baudrate=baud_rate, timeout=time_out)
+ ser = serial.serial_for_url(port, baudrate=baud_rate, timeout=1)

brewpi.py ~ line 345
- inWaiting = ser.inWaiting()
+ inWaiting = ser.readline()

- newData = ser.read(inWaiting)
+ newData = inWaiting

Appears to be working

thekraken · Oct 14, 2015

dibbz said:
1. The esp8266 was roached, luckily another arrived from China no packet loss.
2. the serial.inWaiting() appears to not work with socket://, I'm no python expert. The subroutine that gets the version uses serial.readline() and works.

So with this in mind, in addition with the config change;
BrewPiUtil.py ~ line 129
- ser = serial.Serial(port, baudrate=baud_rate, timeout=time_out)
+ ser = serial.serial_for_url(port, baudrate=baud_rate, timeout=1)

brewpi.py ~ line 345
- inWaiting = ser.inWaiting()
+ inWaiting = ser.readline()

- newData = ser.read(inWaiting)
+ newData = inWaiting

Appears to be working

Interesting. It worked for me without having to make these changes. So before this change you were getting nothing after the version?

GrogNerd · Oct 14, 2015

forgive my total ignorance on what's going on here, but I need a little clarification

so, what this $5 doohickey does is change the configuration from the top figure in this pic to the bottom?

thekraken · Oct 14, 2015

That's about right. But the rpi could be swapped for a desktop in the next room, and then multiple arduinos (wirelessly) attached to it. For example you could have 1 rpi that controls your kegerator in your kitchen and your keezer in your garage without having to buy an additional rpi.

How to set up multiple instances on a single rpi is beyond the scope of this thread though.

dibbz · Oct 14, 2015

You could run the brewpi in the cloud

Anyway my test setup is a debian wheezy 32bit vm, everything up to date, python modules, os packages, brewpi stable from the git repo dated Aug 5th.

If I change dumpSerial to True in BrewPiUtil.py and run brewpi.py I saw the commands get pushed but no replies after the version subroutine;

Code:

root@brewpi-test:/home/brewpi# sudo -u brewpi python /home/brewpi/brewpi.py
Oct 14 2015 11:53:38   Opening serial port
 Oct 14 2015 11:53:38   Notification: Script started for beer 'My First BrewPi Run'
 Oct 14 2015 11:53:48   Checking software version on controller...
nN:{"v":"0.2.4","n":40,"c":"2a6f7f05","s":2,"y":0,"b":"s","l":"1"}
 Oct 14 2015 11:53:48   Found BrewPi v0.2.4, running commit 2a6f7f05 build 40, running on an Arduino Uno with a revC shield on port socket://10.69.69.25:23

sctttt

The first difference that would probably hold the answer is that you do did not need socket:// but this is quite well documented in the py serial docco and would not work for me.

I'm running Python 2.7.3 and pyserial 2.7.

dibbz · Oct 14, 2015

I just installed a fresh Ubuntu 14.04 LTS 64bit VM, installed brewpi via the guide and made the changes as I described, and can confirm it's the same result.

GrogNerd · Oct 14, 2015

just have the one arduino controlling the fermenation fridge, so we're good there.

with all the restrictions on my setup, this sounds like a great solution.

thekraken · Oct 14, 2015

GrogNerd said:
just have the one arduino controlling the fermenation fridge, so we're good there.

with all the restrictions on my setup, this sounds like a great solution.

Check out the Bluetooth brewpi thread too.

dibbz · Oct 16, 2015

It's worth reporting that the ESP-01 also works with avrdude when you set the pin assignment to esp-01(AVR) and connect gpio0 to the arduino reset.

thekraken · Oct 16, 2015

I had problems with that if I powered the esp off and back on. (At the time) it seemed to need gpio0 for it's own purposes while powering up.

day_trippr · Nov 23, 2015

Parts finally arrived and I've cobbled together an esp-03 based module with an LDO 3.3V regulator.
It's 1.125" x 1.75" overall, not too bad.

Checked out the regulator before wiring in the esp, but I haven't powered the whole thing up yet - mostly because I haven't figured out what to expect from an "out of the box" esp module yet.

Turns out the current versions of esp-link (pretty much everything from 2.0 on) requires a minimum of 1MB of on-board flash, while the esp-03 only has .5MB. The last working version that supports the esp-03 is 1.04(b1) which fortunately still has a home on Github, but a lot of documentation has moved past the esp-03.

Also looks like the programming environment only runs under Linux?
Not that huge a deal - I can use one of my RPi boxes I suppose.

And it seems I can't pull a full MAC address out of this thing all that easily. Obviously it needs to show up on my network - which normally has MAC filtering enabled. At the minimum I'll have to turn that off until I can get this thing to talk to me somehow.

Anyway, more as I stumble through this

Cheers!

thekraken · Nov 23, 2015

I didn't know they have outgrown the 03. I went with the 03 as that was what the developer was working with at the time. Maybe there are other wifi serial bridges that will get the job done? FYI, in case you don't already know, with the 03 I had to connect pin15 to ground with a 1k resistor.

[Edit] For the initial flashing of the 03 module I had to used a windows application called ESP Flash Download Tool V1.2, this was the first flashing software I came across that would work reliably. At that point I could follow the instructions from the esp-link wiki to upload its firmware. Of course, once you get an initial version of the esp-link firmware running you can upload updated versions wirelessly with the included scripts.

I dual boot, a flavor of *nix is usually my primary os, I'm sorry it didn't occur to me to mention this from the beginning. You can use a virtual machine on your windows machine if you don't want to mess with your pi for development, I like virtualbox for this. I guess I figured if you're using a pi your using linux.

I may be wrong but I think the developer provides the compiled binaries for the firmware, you can upload this using the windows software I mentioned earlier. If you want to hack the esp-link code or flash the firmware remotely that may require a *nix machine.

father_jack_hackett · Nov 23, 2015

I hope this is of help. I used this firmware which is very basic when compared to esp-link.
https://github.com/beckdac/ESP8266-transparent-bridge
Hence my assumption that it is small enough for your module. I programmed the firmware in the windows environment. There are a host of programing tools out there that run on windows, most don't seem to work. I will find out, which ones I used and post them here, when I program the next one expected in the post soon. I gave up on the bluetooth modules because of stability issues, and poor range. The blue tooth modules work great, but I found I had to reboot the pi whenever there was a problem which was about 2 or 3 times a day. The wifi modules seem to be more robust at staying connected. I am also migrating the whole environment off the pi and onto wheezy running in virtual box, in the hope of having a more stable environment. I will add more info soon. Hope this is some help.

http://www.byvac.com/index.php/BV107. I think this is what I ended up using, based upon the above firmware. I must try documenting what I do, to stop going round in circles.

dibbz · Nov 23, 2015

esp-link 1.0.4 is stable/fine, I've done a few brews on wifi now. I'm running ubuntu 14.04 lts for brewpi on a vm as wheezy is old as the hills.

I used a cheap logic converter like this one, if you use the tx/rx off the arduino you will toast the esp with 5v.

I just stuck it all on a prototype board and used it as is.

Also in this pic is the cable i made to program the esp-01, guess I'm lucky my $1 ttl adapter can supply enough 3.3v to do this.

thekraken · Nov 23, 2015

dibbz said:
esp-link 1.0.4 is stable/fine, I've done a few brews on wifi now. I'm running ubuntu 14.04 lts for brewpi on a vm as wheezy is old as the hills.

I used a cheap logic converter like this one, if you use the tx/rx off the arduino you will toast the esp with 5v.

I just stuck it all on a prototype board and used it as is.

Also in this pic is the cable i made to program the esp-01, guess I'm lucky my $1 ttl adapter can supply enough 3.3v to do this.

So its been working stable for 3 fermentations? Any issues to speak of?

flamingBurrito · Nov 23, 2015

This is an awesome project. I think I'm going to order one of these (http://www.adafruit.com/product/2471) esp8266 breakout boards. Comes with a built in voltage regulator. I could get a voltage regulator and wire it up myself but I'm lazy.

Just wanted to clarify one thing, you are just wiring up the TX and RX from the esp to the arduino, correct? The TX of the esp to the RX of the arduino and vice versa?

Edit:
Just answered my own question by looking at the esplink page. Gonna set this up as soon as my fermenter clears up. Don't want to be messing with it while I have stuff fermenting in it

thekraken · Nov 23, 2015

I used a voltage divider circuit for the rx/tx, you could also use a logic level converter or just use a 3v arduino. You don't want to wire a 5v arduino directly to the esp.

dibbz · Nov 23, 2015

thekraken said:
So its been working stable for 3 fermentations? Any issues to speak of?

None, just works

Actually better than before as I ran the old set up on a powered usb hub and had the occasional communications issue over USB to the arduino, and now I use a 9v 1a plug pack and no USB.

On the topic of 3.3v arduinos, I believe the relays like 5v.

flamingBurrito · Nov 24, 2015

thekraken said:
I used a voltage divider circuit for the rx/tx, you could also use a logic level converter or just use a 3v arduino. You don't want to wire a 5v arduino directly to the esp.

Yeah the breakout board I linked to has a level shifter built in so you can just wire 5V straight into it. If you're not using the breakout board, you'll need to bring it down to 3.3V.

day_trippr · Nov 24, 2015

I have a fundamental question about bringing up a brand new esp (an esp-03, in this case): if it's powered up (and has the apparently required 1K pull-down on GPIO15) how does one actually talk to it?

It's not going to be able to connect to any wifi network that requires credentials - it doesn't have any credentials to offer. And if there are a number of strong wifi beacons in range, how's it going to decide which one to even try to connect to?

If it can't connect to an actual network, does it generate an ARP address and go with that - and you have to peer with it?

A little insight would be appreciated, thanks!

Cheers!

flamingBurrito · Nov 24, 2015

You use a TTY cable to program it. See: http://www.esp8266.com/wiki/doku.php?id=getting-started-with-the-esp8266#at_commands

thekraken · Nov 24, 2015

Yep, you'll need to wire it up to your computer the first time and use AT commands to give it a network and key. If you get esp link firmware on there it can boot as its own wifi access point, you then find its network with your device/computer and change its settings via web browser interface instead of AT commands.

I use a usb-bub II to talk to it over wire.

(Edit) also, I had a hard time getting any kind of meaningful response out of my esps until I realized the preloaded firmware was crap and updated to the latest firmware. After I figured out I needed to do that things progressed much smoother. (Keep in mind this was several months ago for me )

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