Random Characters in 20x4 LCD

[TomGeorge]

Hi, @mirobychee

@mirobychee

i havent finished the whole schematic yet but this is the part for the temperature

the big iode is the 6A one

Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.

Forget all the fancy colours, if you like use red and black for 5v and gnd, but do the rest in black and white.
What are the transistor part numbers and pin labels for example.

Sorry but a clear diagram, makes for easy interpretation.
If you have not drawn a schematic before, them now is a good time to attempt/learn.

Google;

basics of drawing an electronic schematic diagram

What are you powering the Mega from 9V on the DC socket or 12V on the Vin pin?

What is this diode for?

Thanks.. Tom..

[mirobychee]

thanks tom im currently still learning how to make a schematic but the colors are needed based on my teacher to distinguish one another

that diode is one of my solutions to inductive loads because when the fan is just wired directly it would sometimes display gibberish

for the vin pin i didnt really know what the vin for and i dont understand it so i just copied exactly from the video i watched but he used arduino nano from that and he doesnt have an adapter for the arduino but for me i used both one for the arduino and one from the vin idk if that would cause a problem

thankss

[mirobychee]

this is the finished schematic of what i have at the moment can you help me find the problem? thank you

edit: i forgot to add the schematics for the button but its basically just 3 buttons for the selection of plants

the 3 buttons re connected to the 5v and gnd snd each has a pin to 51, 52, 53

[J-M-L]

@mirobychee

the 3 buttons re connected to the 5v and gnd snd each has a pin to 51, 52, 53

Do you have a pull down resistor for the buttons?

It’s better to connect the button to GND and use an input pull-up (the one directly available in your arduino - so no need for an extra resistor)

[mirobychee]

what i did is basically the 3 gnd of the buttons are connected to ground and the 5v are connected to a 220 resistor each and then connected to the positive then all those buttons have each pin for the arduino

the screws are just there to keep them in place

[J-M-L]

I can't really tell what is what

a pull down should be wired like this

if buttons have 4 legs, wire diagonally across the buttons to make sure you don't pick the connected pins by mistake.

[mirobychee]

how do i connect the diagonal?
with a resistor? if so should i remove the initial resistor?

[J-M-L]

what I mean is this

when you have 4 pins on your push button, you really have only 2 different ones. Internally they are connected. So if you want to be sure to include the switch in your circuit and not make use the same pin, you wire diagonally across the button and this way you are sure to not have an issue. (unless you really want to use the same pin).

we would typically not use a pull-down circuit with an extra resistor and wire 5V to the button (risk of short circuit if things go wrong). It's better to connect to GND and use a pullup. see https://docs.arduino.cc/tutorials/generic/digital-input-pullup/

[mirobychee]

in my circuit the one connected to arduino is in the same line with the 220 and negative then the opposite is connected to the positive and the connection is empty

[mirobychee]

can the button be the problem for the lcd or are u just recommending?

[J-M-L]

If the button is not wired correctly and creates a short then it’s an issue.

I can’t tell from the picture you posted if you pulldown is correct

Does the wiring look like the one in post 26?

[mirobychee]

i cant really figure out because im not familiar with it could you send me a picture of a button with pulldown resistor?

[J-M-L]

does this help?

[GolamMostafa]

[J-M-L]

yes, GND being the GND of the Arduino was implicit

[amic]

Hello

The 6A10 diode will suppress one of the two alternating currents supplying the heater plate, thus reducing its power.

Was this the intention?

[mirobychee]

yes but sometimes it still display errors for some reason i have no idea how to debug it

[mirobychee]

this is the finished schematic the button are at the bottom right it seems like my circuit is different.

edit: nvm i think its the same my GND and set pin are just on the opposite sides