Baracuda + Micro

[Teleno]

Right... advice time... which protocol to use...
Mike

I2C only uses 2 wires and can address multiple chips. Downside: most ICs are SMD. Upside: cheaper, broad choice.
SPI uses 3 wires plus one chip-select per IC. Upside: DIP package available. Downside: less but still, more limited choice.

It all depends on your soldering abilities and nr. of available I/O pins.

[Michaelo]

I2C only uses 2 wires and can address multiple chips. Downside: most ICs are SMD. Upside: cheaper, broad choice.
SPI uses 3 wires plus one chip-select per IC. Upside: DIP package available. Downside: less but still, more limited choice.

It all depends on your soldering abilities and nr. of available I/O pins.

The big advantage of SPI is probably DIP packages for hobby builds and there are a lot of inexpensive TFT displays should anyone want to change...
I think I actually bought a small board that interfaces with any 16/60 char 2/4 line LCD to SPI and from memory it was not inexpensive... must root it out...

[ivconic]

The big advantage of SPI is probably DIP packages for hobby builds and there are a lot of inexpensive TFT displays should anyone want to change...
I think I actually bought a small board that interfaces with any 16/60 char 2/4 line LCD to SPI and from memory it was not inexpensive... must root it out...

Ok if you plan versatility for your code than leave I2C uncommitted by now.
Use SPI instead.
Why?
Because later you may want to engage I2C for other peripherals.
For example; one of the code versions can still use ordinary 16x2 (20x2) LCD through I2C adapter (nice option, gives you more free pins).
Or you may want to add external I2C eeprom, or something else.

I am having these:

[Michaelo]

Ok if you plan versatility for your code than leave I2C uncommitted by now.
Use SPI instead.
Why?
Because later you may want to engage I2C for other peripherals.
For example; one of the code versions can still use ordinary 16x2 (20x2) LCD through I2C adapter (nice option, gives you more free pins).
Or you may want to add external I2C eeprom, or something else.

I am having these:

[ATTACH]35936[/ATTACH]

Looks like the one I got...

I think I'll be changing to a 16x2 LCD, as the 20x4 is too large and would make the case far too big...
Just ordered a couple of 16's for $5 but now I'm tempted to use the spare 1.8" TFT as it is SPI... decisions decisions....

Even with the SPI, I would prefer to control the contrast with the processor... there goes another pin...

[ivconic]

Looks like the one I got...

I think I'll be changing to a 16x2 LCD, as the 20x4 is too large and would make the case far too big...
Just ordered a couple of 16's for $5 but now I'm tempted to use the spare 1.8" TFT as it is SPI... decisions decisions....

Even with the SPI, I would prefer to control the contrast with the processor... there goes another pin...

"...I think I'll be changing to a 16x2 LCD..."

Excellent decision. Easier to obtain, cheaper etc.

"...but now I'm tempted to use the spare 1.8" TFT..."

Also tempted to see it. Two versions of code; one with LCD and another with TFT, to suit all the demands!

"...Even with the SPI, I would prefer to control the contrast with the processor..."

For a start onboard trimmer will do, until you see if there will be any spare pins at the end.

[eclipse]

I don't think TFT displays have good contrast under direct summer sun.

The OLED display with SSD1306 is fairly small, 1", Also very simple do drive, it will take only 2 chip pins, it's fairly cheap, also
there's a lot of code examples available:

http://elegantcircuits.com/2014/08/2...control-panel/
http://elegantcircuits.com/2015/02/0...with-attiny85/
http://elegantcircuits.com/2014/08/1...-i2c-protocol/
https://github.com/tibounise/SSD1306-AVR

---

Dual axis rocker Thumbstick "PS2" type can replace all keys & buttons:
https://tkkrlab.nl/wiki/Arduino_KY-0...oystick_module

You can save few outputs for keys if you use 1xADC like this:
http://cdn.instructables.com/F3A/0SD...W03.MEDIUM.jpg

[Michaelo]

Which Display:
Not being able to see the TFT type display under sunny conditions probably puts pay to that idea...
The same may be true for the 16x2 LCD but I may as well finish it...

So is the OLED potentially the best choice in relation to being able to see it on a summers day and also a low pin count and excellent price.
If so, the only disadvantage is the small size... can we get a bigger one for small money or simply use larger fonts...
I will grab a couple for testing...

Save Some Pin:
If we really get stuck and need to save pins then the resistor chain on an analogue input is an option.
I've done it before and it works but not as fast as the current arrangement, plus we already use the ADC to monitor battery...

Switching to an OLED (or a larger OLED) would appear to have the most gain... Best sunlight visibility and fewer pins required (assuming it is more visible that is)...

We could go with the 16 LCD and the OLED at the same time...


Input:
Touch screens demand lots of pins so probably not feasible on this occasion but could be with a daughter board converting to some serial communications...
A small Joystick type control (as in link) would be nice but are they rugged enough?

Then there's the question of mounting the display and keys...
It's probably best to use have them PCB mounted as mounting these separately with wire everywhere is a complete pain...

The PCB size should be only slightly larger than the current bara but it all depends on what display and key(s) we adopt...

It goes without saying, nothing is written in stone...

Mike

[Teleno]

Best sunlight visibility is achieved by transflective LCD displays that don't require a backlight. For example, Nokia 5110 that's very cheap and has an Arduino library.

[Michaelo]

Best sunlight visibility is achieved by transflective LCD displays that don't require a backlight. For example, Nokia 5110 that's very cheap and has an Arduino library.

Pros:

• Saves two wire over LCD
• Works best in Sunlight (optional backlight in the dark)...
• Tried and tested design...
• Lots of code samples...
• Low Cost...

Cons:

• A bit small...

I have some in stock so testing won't be delayed...
Any more pros or cons?

I do like it but I would like a bigger display...
Are the OLED's not as good? (I have never use one so I don't have a clue)...
Mike

[Teleno]

Larger, transflective LCD 128x64 dots http://www.aliexpress.com/item/LCD-1...611198105.html

[ODM]

They used antireflect finished polycarbonate for 5110 windows, too. Something to look for when adding a mudguard window, AR-film might be as good though gets scratched easier.

Something resembling early CRT sunguard pipe would probably work for hobby purposes if bright light becomes a bother for an existing display

[eclipse]

128x64 OLED - 2.42" with same controller SSD1306

https://www.adafruit.com/products/2719 -
http://www.ebay.com/itm/I2C-2-42-128...-/131332928598

[Chet]

I have seen a do-it-yourself detector with a Yellow OLED that was great in daylight and in shade. Some other displays work well in sunlight but need a high backlight level in shady areas and on cloudy days. The small 1” displays are hard on us old guys with glasses.
Have a good day,
Chet

[6666]

couple of points from an end user
Cheap and easy to obtain is best, the more complicated you make this display the harder it will be for different people around the world who have limited access to parts to make
and really how often are you going to look at the display ? once the parameters are set there is very little need to look at the display .
Useing a display that runs from 5 volts would be an advantage over having to level shift with something that runs on 3v.

[Teleno]

Too much emphasis in the display.

Up/Down buttons and menus are OK for semi-permanent adjustments, but when you need to ajust frequently nothing beats rotary knobs. Regular pots + A/D converter are the way to go. The MCU can detect which know is being changed and select the menu automatically displaying the adjustment values without manual menu selects.