How To: BrewPi LCD Add-On

I found a good discussion of potential causes of LCD scrambling here:
http://hackaday.com/2014/02/27/fail-of-the-week-reset-issues-with-595-and-hd44780/

 

Read the whole thread, and along with the specific issue (programmed reset failing) nothing there really applies to our noise problem...

Cheers!

 

How about using some wire that's shielded to the LCD?

 

Shielding is unlikely to be the answer to voltage/gnd sag - what I think is really going on.

I'd be interested in knowing if the folks having LCD scrambles are powering their Uno's via USB versus a dedicated 9-12VDC wall wart...

Cheers!

 

Since you haven't finished building yours yet you might find you don't suffer from the problem when it's done.

I read a bit about the issue today, and mostly the solutions came down to these:

• Decoupling capacitors
• Reset delay time in the firmware
• Change the LCD module

 

I have another Idea to solving this Send a shield to this guy. He solved an issue for the first guy in the video with the PCB design which is at 2:45mins into the video and after that skip to 29mins and hes looking at a pretty cool arduino prototype board. Maybe if you send in a shield he could put it on his setup to test it?

[ame]https://www.youtube.com/watch?v=VKJ1h6ThW3Y[/ame]

If youtube link stops working then search on youtube for "EEVblog #888 - Mailbag"

 

Yet Another Waste of Time...

 

Well if someone would be nice enough to supply a gaber file that would be great then I can supply it to have them look at it If you cant solve it yourself then no harm in asking for help

 

@day_trippr ... do you have a recommendation for a cleaner after assembly? When I worked for that company we had a big-ass dishwasher but somehow I think that might be a bad idea ...

 

I use this stuff in a big aerosol can...



It does tend to leave a haze so if I'm going to be taking pictures I'll follow it with soap and water and blow it dry with compressed air...

Cheers!

 

TY sir!

 

This link still working for folks? I only see five parts on the list...

 

You don't have the P-FET on the board, and I don't see a modification either. Are you running the 5V to the diodes for the backlight?

 

There is something screwy with that link.I had 18 different parts when I ordered.

 

Thought so. When I looked at it a few weeks ago it was a full list. I can make up my own order--unless you have a saved list somewhere...

 

Mfr. # Manufacturer Desc. Customer Part # Order Qty.
85 Adafruit Adafruit Accessories Shield stacking headers for Arduino (R3 Compatible) Adafruit 1
SN74HC595N Texas Instruments Counter Shift Registers Tri-State 8-Bit U1 1
BSS84 Fairchild Semiconductor MOSFET SOT-23 P-CH ENHANCE U2 1
110-13-316-41-001000 Mill-Max IC & Component Sockets 16P GLD PIN GLD CONT Socket 1
450-4760 Eagle Plastic Devices Knobs & Dials SOFT TOUCH D SHAFT Knob 1
ACZ11BR1E-15FD1-20C CUI Inc. Encoders Encoders Rotary Encoder 1
22-28-4183 Molex Headers & Wire Housings 2.54MM BREAKAWAY Vertical 18 CKT Gold Headers 2
1N4001 Fairchild Semiconductor Rectifiers Vr/50V Io/1A T/R D1, D2 2
CF1/2CT52R200J KOA Speer Carbon Film Resistors - Through Hole 20 ohm 5% R10 1
MF1/4LCT52R221J KOA Speer Metal Film Resistors - Through Hole 1/4 WATT 220 OHM 5% R9, R11 2
MF1/4LCT52R202J KOA Speer Metal Film Resistors - Through Hole 1/4 WATT 2K OHM 5% R8 1
CF1/4CT52R102J KOA Speer Carbon Film Resistors - Through Hole 1K ohm 5% R7 1
MF1/4LCT52R472J KOA Speer Metal Film Resistors - Through Hole 1/4 WATT 4.7K OHM 5% R6 1
CF1/4CT52R103J KOA Speer Carbon Film Resistors - Through Hole 10K ohm 5% R3 - R5 3
299-10K-RC Xicon Carbon Film Resistors - Through Hole 10Kohms 5% R2 1
3296Y-1-103LF Bourns Trimmer Resistors - Through Hole 3/8" 10Kohms Sealed Vertical Adjust R1 1
SR205E105MAR AVX Multilayer Ceramic Capacitors MLCC - Leaded 50volts 1.0uF 20% C8 1
1C10Z5U104M050B Vishay Multilayer Ceramic Capacitors MLCC - Leaded 0.1uF 50volts Z5U 20% 2.5mm L/S C1 - C7 7

 

here is a pdf

View attachment Project_Apr13_1056PM4.pdf

 

It's invisible

Nah...I forgot to solder it before I took that pic.
Pretend it's there and everything else is strictly according to Hoyle...

Cheers!

 

I've finally put together an "instructable" on how to solder up the board, including the parts list. I've put it on the DIYBrewPi Wikia for posterity's sake and because this thread is very long. Feel free to edit the wiki page if you find errors or have suggestions.

Here's the link: http://diybrewpi.wikia.com/wiki/BrewPi_Shield

As always, thanks to @day_trippr for the help and for the project to begin with.

 

Sorry, just saw this post. Not sure why the Mouser project has been reduced to just the five parts. Check out the wikia page http://diybrewpi.wikia.com/wiki/BrewPi_Shield for a complete parts list for the shield. Hope this helps.

 

bit later in replying i know, but yes i've tried both ways, powering arduino direct via dedicated power source and also via USB only.

didn't seem to make a difference, as i mentioned previously the only way i've got it to not scramble is to use an SSR, and even then it would ever so occasionally scramble, but only during a short period when i was using the fridges door light as a heater.

 

I found some 3A power supplies so I'm going to try those if I have an issue and see if they help.

 

Did it help?

 

What is the reason to use Bluetooth attached to shield? And the Rotary encoder is used for what? About resistors, what is the best kind of? metalic, ceramic....? About resistors power, the value shown (ex 1/4W) this is the minimum power desired?

 

- to enable wireless Arduino agents
- to allow programming at the Arduino
- the resistor type is non critical, use whatever is easily available
- 1/4 watt is the most commonly available axial lead resistor

Cheers!

 

@daytrippr, thanks for you fast reply.

About "to enable wireless Arduino agents" is used to connect Arduino to RPi/PC? And about "to allow programming at the Arduino" Could we programming Arduino w/o web interface? I didn´t undestand well how to for both questions, could you explain a little bit more?

Thanks again,

Fabiano

 

@CadiBrewer, is it possible use your board without BSS84? What this component do? I am having difficult to find it in Brazil. Is there other name/reference for this component?

Thanks,

Fabiano

 

- If you want to control multiple chambers that are too far apart for USB connections, adding a Bluetooth - or Wifi - radio to the Arduinos solves that connectivity problem.

- The encoder provides a method to change some high-level runtime settings from the Arduino end. This is fully explained on the BrewPi site...

Cheers!

 

The bss84 p-channel mosfet deals with the auto shut off (dimming) of the LCD screen. Yes, you can use the board without the component if you don't mind having the screen always on. You would just solder a small wire between two of the three pads on the board. You want to tie the drain and source pads together.

If you look at the three pads as a triangle, the drain pad is the top of the triangle. The source pad is the bottom right leg of the triangle. Solder a small piece of wire between the two pads. You can use a cut off piece from one of your resistors.

@day_trippr, I'd appreciate you making sure I have stated that correctly.

Sorry for the lack of a clarifying drawing for what I'm trying to explain, but I'm not at home or near a for a few days.

 

Has anyone worked out what was causing the scrambling issue?

 

Yes, it was solved on the hackaday link. It's caused by the lcd powering up later than the microcontroller. One commenter solved it by powering the lcd from a transistor activated by the microcontroller.

 

That is definitely not the problem here...

Cheers!

 

@CadiBrewer, thanks for explanation. From the file attachad (P-fet), I have to link D (3) with S (2)? May I ommit also PNP transistor? PNP transistor do the same of P-fet (shut off LCD)?

About LED, those have 2 poles. One pole should be linked to anode after resistor and the other should be linked to GND?

Thanks.

 

I didn't even get my shields built yet so no problems yet, so no, they did not help anything. They are still sitting on my bench.

I just got back from a week in Galveston so maybe I'll get to work on them.

 

For what it's worth, I haven't had a scramble issue for over 4 months of use, with my ferm chamber in a 100+ degree garage with the freezer kicking on multiple times per day. I built my setup with the shield and used a separate power supply for the UNO as @day_trippr suggests.

I had the screen scramble once during the first week of use. I believe that one of my kids dropped the unit, jostling it enough to short something out inside. Since then, no problems whatsoever.

 

Nope, not to GND. The other LED poles should be linked to I/O 5 and I/O 6, which are the same I/O ports that are linked to the cool and heat functions that switch on the relay board.

 

Sorry, I missed this part of the question. Yes, the PNP transistor does the same thing as the p-fet. If you wanted to auto shut off the LCD screen, you would use either the p-fet or the PNP transistor. The board that I designed uses the p-fet. If you use the protoshield board that day_trippr designed you can use either option. If you don't want the screen shut off, eliminate both.

 

Ok so do you have a link to the change to the design to solve the scrambling issue?

 

One comment says a common issue is the 595 being incorrectly wired
http://hackaday.com/2014/02/27/fail-of-the-week-reset-issues-with-595-and-hd44780/#comment-1233030

If you don't have that issue then another says power cycle the lcd periodically as the firmware has a bug that causes it to get out of sync. I have experienced the bug over I2c myself.
http://hackaday.com/2014/02/27/fail-of-the-week-reset-issues-with-595-and-hd44780/#comment-1816924

I don't have a schematic for the design but use a 2n2222 with emitter to uno ground and collector to lcd ground. then use a 1k resistor betweeen a digital output pin and base.

 

Got My pi fermention working by puré luck and use of this forum.

Now ofcourse i want à lcd .
But realise that i Will nerver be able to build one.
Is it possible to use this https://www.ebay.com/itm/121099129816