Hi. I purchased LCD-10862 for use with the Variable Load kit. I noticed that on the standard “basic” one color 16 pin LCD,
that pin 15 is A +4.2 V and pin 16 is K (0V).
However, on the RGB LCD-10862 pinout, it lists pin 15 as K and pin 16 as A-RED (opposite of “basic” LCD.
What is the correct way to connect LCD-10862 to the load board? Do I need to swap pins 15/16 for to connect it correctly?
Thanks!
Jaime
Hi Jamie,
Pins 15 and 16 on the Variable Load Kit are actually not connected to anything so powering the backlight for the RGB LCD will require running a couple of wires to use one of the colors. The easiest option would be to run a power and ground wire to the 5V and Ground pins on the side of the Load Kit mainboard like this (assuming you want to use the Red LED for your backlight):
Excuse the MS paint and bad coloring (just to clarify, green=Vcc/5V and black=Ground) and just make sure to add a 330ohm resistor in series with the power line for your Red LED and that should work to power the backlight. If you wanted to use the other colors, you would just run the wire from 5V to whichever color LED you want along with that 330ohm resistor to limit the current.
I hope this helps you hook up your RGB LCD with the Variable Load Kit. Let us know if you have any other questions or concerns about using these products and we would be happy to help as much as we can.
Hi TS-Mark. Thank you for the help/clarification. This info should be included in the instructions for pairing these two parts together! I hope for the sake of other customers that this happens.
Much appreciated!
Jaime
Hi again. One more thing if you don’t mind.
Is the “LOAD ON” LED supposed to REMAIN on after pressing enter? or just flash green quickly and turn back off? The Hookup Guide says " The “Enter” key turns the load on or off …" but I’m unsure what state the LED should show if it is working.
Thanks!
Jaime
The LOAD_ON LED will be on when the load is active and should stay on once you press Enter with a load attached. The [Product Demo Video gives a good example of what you should expect to see with the Variable Load Kit powered with a load on the output.](https://www.youtube.com/watch?v=OWPisGTeeXQ)
Thanks again, Mark. Yeah, my LED doesn’t stay on. I hooked up to 2 different 12V DC supplies. The LCD shows the voltage only. Not sure what to make of it.
Hmm, I am not sure what would be going on there at the moment. If you open a serial terminal to control the kit, do you get normal behavior as described in [this section of the Hookup Guide? Also, can you take a few photos of the top and bottom of your kit and attach them to your reply? Please do your best to make sure they are clear and well-lit.](https://learn.sparkfun.com/tutorials/variable-load-hookup-guide---revised#operation)
Hi Mark. This forum will not let me drag/drop attach photos for some reason. I get “HTTP Error”. Is there another way for me to get jpgs to you?
I will try hooking up a laptop to the board soon and let you know what I find.
Thank you!
Jaime
Hi Jamie,
You should be able to attach photos using the “Reply” button or clicking the “Full Editor & Preview” when you open the Quick Reply option and then underneath the “text box” select “Upload Attachment”. You can either put them inline or just leave them at the end. Alternatively, you can host them on something like Google Drive and link them in your reply. I use [this page for instructions on adding images and a whole host of other formatting options for the software our forums run on.](phpBB • BBCode guide)
Hi again. I am getting the same error. I will check with our NW admin to see if it is on our side.
Hmm, if you cannot upload the photos and your NW admin cannot work it out, you may just need to host them somewhere else and link it. If that won’t work, send me a PM and we can work something out to get the photos up.
Hi again Jamie,
I was able to take a look at your photos and nothing stands out in the hardware that would be causing this problem. Does the kit behave normally either displaying to the display or to a serial terminal aside from the LOAD LED? If not, did you by chance test the kit prior to attaching the LCD? Did it function normally then?
Hi Mark.
Okay, thanks for taking a look. I did not test it prior to installing the LCD. I will play with it some more and see if there is something I am missing here. Then if it doesn’t work out, I can try to remove the LCD and see if it changes anything.
Thanks for you help!
Jaime
The display really should not affect the functionality of the firmware so I would leave removing the LCD as a last-ditch effort unless you have the right tools for desoldering PTH components. Try testing via serial terminal and with the display to see if you can get the Load Kit working as expected.
I’ll let you know how it goes. Probably next week.
J
Hi Mark. I looked back and found this… “For safety, please be sure that the total load power is limited to 15W because, even at that wattage, the heatsink will get hot to the touch”.
I was attempting to push it over the limit!
It may be helpful if on the product description to give brief examples such as : 15W = 1.25A @ 12V, 3A @ 5V, 0.625A @ 24V, etc.
Thanks for all of your help. Sorry for the goose chase on this last one. Take care!
Jaime
Hey again Jaime,
Ah, that makes sense. I’m pretty sure the board will automatically shut off power if you try and push beyond 15W so that would explain why your LOAD_ON LED was not staying on. That is a good suggestion for clarifying what kind of voltage/amperage would equal 15W so other users do not run into this issue. We’ll look into either adding a couple of examples in the description or possibly in the Hookup Guide (or both!).
I’m glad we finally figured out what was causing that problem and hopefully, your Load Kit is working okay now with a lower load. Let us know if you run into any other issues with this or if you have any other questions about the Variable Load Kit or other SparkFun products, feel free to create another topic and we would be happy to help.
Happy hacking!
