Reef Discussion

Buddy

Member
Mar 13, 2012
3,142
1,526
What's happening here - @newbiereef has tried flattery and now @VaultBoy is trying the guilt trip :p

Just out of interest, for those that might be interested, who would like the hardware to be provided i.e. everything needed to plug it in and connect up to your LDD boards. I have some Arduino Mega's, LCD screens etc and may be prepared to find some more if there is sufficient interest. A box or two to put everything in is not available at this stage although I am playing around with a few ideas, with no guarantees.
Put me on the list for a plug in and play :D
 

James Smith

Member
Jul 31, 2013
3
1
Nice work Magic :) ty for the LDD's and boards the other day and a bigger ty for putting up with dumb questions :)

LED's, Sink etc have finally left the states, now the race begins... Magic Vs USPS :)
 

MagicJ

Moderator
Jul 11, 2011
9,650
3,761
Hobart, Tasmania
Nice work Magic :) ty for the LDD's and boards the other day and a bigger ty for putting up with dumb questions :)

LED's, Sink etc have finally left the states, now the race begins... Magic Vs USPS :)
Hi James - good to see you on The Reefuge :)

So, what is the expected delivery date of your parcel?? And how long will it take for you to put it all together ?

I need to know what I am up against before I accept a challenge :p
 

Sam Parker

Moderator
May 6, 2013
4,802
2,397
Geelong
Please add me to the list. I am happy to work with a plug and play system or one that requires a bit of soldering.

Cheers,
Sam
 

longlenium

Member
Jul 22, 2013
30
10
Hi @MagicJ
can you please put in on the list!!!
if you got them ready
where do i pay?
Showwwwwwwwwwwww me your account lol .. take my money
 

James Smith

Member
Jul 31, 2013
3
1
Problem Magic......
USPS must have money on me winning the race....

Scheduled delivery of LED's etc is tomorrow, over a week ahead of schedule :)
 

MagicJ

Moderator
Jul 11, 2011
9,650
3,761
Hobart, Tasmania
Baby clowns are looking after themselves pretty well at the moment so probably time to get this project finished :rolleyes

The Arduino's are designed as a development board i.e. you use them during the design phase of your project and then make up your own board including just the parts that you actually need. Whilst this is nice in theory, I don't have the skills to design my own boards and it would also make it hard for anyone else thinking about copying my controller.

So, we have to overcome the limitations of the Arduino Mega..... when joined to the TFT LCD board and the LCD shield, access to most of the pins is blocked. We need access to some to control the Real Time Clock, PWM board and a few others for some fun stuff - temperature IC's etc. This is the standard Arduino Mega
Ard-1.jpg


Most of the pins on the right are required for the LCD so we will leave those alone. The blocks in the bottom right and centre are analog pins which we don't require so we will leave those alone as well. The block on the bottom left include power (5v and 3.3v) and Ground which we need. We also need access to the blocks on the top right and top left - the block in the top middle is used for the SD card on the back of the LCD screen which we will not be using but we will leave these alone just in case we need the SD card at some stage.

If you grab hold of the plastic blocks with some pliers etc and pull gently, but firmly, they will lift off revealing the individual connectors.
Ard-5.jpg


Using your soldering iron to melt the solder you should them be able to remove all of the individual connectors - you may want to clean up the remaining solder with some de-soldering braid.
Ard-4.jpg

I then soldered in some 90 degree male headers to make for easy connections - 2 in pins 20 and 21 (these are the I2C lines) and 7 into pins 8 to 13 + GND - we don't need all these pins at this stage but we might do :rolleyes - this is what it should look like.
Ard-3.jpg


The power block (lower left) is used by the LCD so we can't remove it. But, if you were careful removing the plastic blocks and the connections you can re-use one of the blocks - re-insert the pins and solder it onto the power pins on the reverse of the board - like this
Ard-2.jpg


Hopefully, you won't have broken anything and can now get access to all the pins that you need.

More coming soon :)
 

MagicJ

Moderator
Jul 11, 2011
9,650
3,761
Hobart, Tasmania
Next we have to fix the LCD backlight. For a controller which will be powered 24/7 we don't really want the backlight turned on permanently. By default, the backlight is connected directly to the Arduino 3.3v pin.

First we have to hack the LCD shield. This is done by removing the pin which plugs into the Arduino 3.3v connector and replacing it with a 90 degree male header.
Ard-6.jpg


It would be nice if we could just connect this pin up to a standard digital pin but, unfortunately things are not that easy. First off, the standard pins work at 5v which is too high for the LCD backlight which operates at 3.3v. Also, the backlight draws around 70mA which exceeds the maximum allowed on an Arduino pin of around 40mA.

The solution is to use a transistor as a switch and connect it between the 3.3v pin on the Arduino and the backlight pin on the LCD shield. We also need to have easy access to the Arduino 5v and Ground pins so I combined the transistor switching circuit with a few additional power pins. This is the schematic for a small PCB I have made up
Ard-10.jpg

And the completed PCB
Ard-7.jpg


To wire these together I made up a wire harness using some Dupont pins and housings - these are a pain to use, although I suspect the wire I was using was a bit too thick. Lucky the pins are cheap as I managed to waste quite a few.
Ard-8.jpg


And, all put together (from the back)
Ard-9.jpg


Next, I need to connect up the Real Time Clock and PWM board.....