How to connect two arduino board, one connect to keypad and one connect to lcd

[vayne]

Hi im a newbie here, and i have a project to make something with 2 arduino board. So i want to make keypad password with lcd, can someone help me how to connect arduino 1 board that connect to keypad, and the other one that connect to lcd ?
thanks

[UKHeliBob]

Welcome to the forum

Are you being forced to use 2 Arduinos ?

[GoForSmoke]

Here is an LCD "backpack" for standard LCD's.

You could make your own and if you don't count the time spent, make one (perhaps bigger and messier) for less.

One thing about being new is that you don't know much about options whether BUY or DIY and that can have you inventing unnecessarily and messy.

Have you ever heard of "pin multipliers"? Those are chips/modules that you can connect to a controller board where 2 to 4 controller pins can give you many-many extra pins for IO. Those pins will have limits on how you can use them depending on what you connect but there is a wide range to choose from.

One choice is to use standalone AVR chips, essentially the chip an Arduino would use, which is what the Backpack is, on your own board or even without, I kid you not!

DIY options include:

Examples of soldering to a bare AVR chip.

If that's too bare, it's possible to solder components to a chip socket (Uno R3 has a socket onboard that the chip plugs into) and plug an AVR chip into that... no board needed. The ATmega328P chip fits on a 28-hole narrow socket but note that narrow form sockets with more holes, like 40, are available pretty cheap. Those extra holes can be soldered to under the socket and jumpers, resistors, leds and other components plug into them. A 40 hole socket can hold a 328P and have 12 extra holes -- a little cheap board as is.

People have wired 8x8x8 led cubes to a single Uno or Nano using 64 shift register chips, 256 resistors+transistors -or- more fewer more expensive led driver chips (no transistors) just to say how far pin-multipliers have been taken... you might find example videos on Youtube.

So there is a glimpse into options you likely didn't know you have. Be sure, there are more!

[gilshultz]

From your description one Arduino UNO (or most other Arduinos) should do the job. It will be much less complicated then trying to use two Arduinos.

Since hardware is involved, it’s crucial to provide an accurate, annotated schematic of your circuit as it is currently wired. Please note that Fritzing diagrams are not considered proper schematics; they are wiring diagrams and are often not helpful for troubleshooting. Hand drawn would be OK. We will help you with this. Remember plus is on top and signal flow left to right. You can do this in parts.

What to Include:

1. Annotated Schematic: Show all connections, including power, ground, and power sources. This helps us understand how your circuit is set up and identify any potential issues.
2. Technical Information Links: Provide links to technical documentation for each hardware device used in your setup. Avoid links to sales sites like Amazon, as they usually lack the necessary technical details. We need complete specifications to help you effectively.
3. Additional Information Needed: If the above details are incorrect, more information is required. Tell us what hardware and software you are using, the format of any data (like map data), and how your system determines its position. For example, if your project involves a robot, describe how it navigates and what computers are involved.
4. Bill of Materials:
5. A schematic provides a visual representation of the electrical connections and components in a circuit, showing how they interact and function together, while a Bill of Materials (BOM) is simply a list of components with part numbers and quantities needed for assembly. Unlike a BOM, a schematic illustrates the design’s logic and allows for troubleshooting and understanding circuit behavior. A BOM is useful for sourcing parts but doesn’t convey how they connect or operate in the circuit, which is critical information for understanding and working with electronics.

Why This Matters:

We have no way of knowing the specifics of your setup unless you provide that information. Clear and detailed descriptions enable us to offer the most accurate help possible. Without these details, it’s difficult to diagnose and solve the issues you're experiencing.

We need the following to accurately answer your question:

• Annotated Schematic: Clearly show all connections, including power, ground, and power sources. This will help us understand your circuit setup and identify potential issues.

• Technical Information Links: Provide links to technical documentation for each hardware component in your setup. Avoid links to sales sites like Amazon, as they often lack the detailed specifications we need to assist you effectively.

Why Do We Want This:

We can’t accurately assist without knowing the specifics of your setup. Clear, detailed descriptions will allow us to offer the best help possible. Without this information, diagnosing and solving your issues will be much harder.

Give yourself an belated Christmas present and pick up these resources, along with the Arduino Cookbook:

• Electronics for Beginners (eBook): Electronics For Beginners (eBook)
• Arduino Step-by-Step Projects Course: Arduino Step-by-step Projects Course | Build 25 Projects"

[DaveX]

@vayne

i have a project to make something with 2 arduino board. So i want to make keypad password with lcd, can someone help me how to connect arduino 1 board that connect to keypad, and the other one that connect to lcd ?

Maybe start by making a plain keypad example work on one arduino, and a plain LCD example work on the other, and then consider what you want to communicate. Simplest would be to check the password on the keypad arduino and then send only a 1-bit LOCKED/UNLOCKED signal to the LCD arduino. If you want more features than that, you need to send more data, and it is much more complicated.

If you want the LCD Arduino to parse some serial and act, perhaps look into some of these erial communication and parsing examples:

@DaveX

Communication

• ASCII Table tutorial
  • Simulation -- Prints a table of characters in decimal, hex, octal, and binary.
• Create a LED Dimmer tutorial
  • (communicates in Binary with processing, not simulated)
• Create a Graph with Processing tutorial
  • (communicates in Binary with processing, not simulated)
• MIDI Note Player
  tutorial
  • (Writes MIDI codes to the serial port, not simulated)
• Use Multiple Serial Ports on the Arduino Mega
  tutorial
• Physical Pixel tutorial
• Read ASCII String tutorial
  • Simulation parses 3 integers from Serial to drive an RGB led.
• Serial Call and Response (handshaking) tutorial
• Serial Call and Response (handshaking) with ASCII-encoded output tutorial
  • Simulation -- Reports sensor data to Serial when prompted.
• SerialEvent tutorial
  • Simulation -- Demonstrates serialEvent() to collect a line without blocking. (could use serialAvailable())
  • See also: Serial Input Basics - updated and @nickgammon on Serial
• SerialPassthrough tutorial
• Virtual Color Mixer tutorial

@DaveX

Non-Arduino Serial communication simulations:

Serial Input Basics by @Robin2

• Example 1 -- Receiving single characters.
• Example 2 -- Receive several chars with an end marker.
• Example 3 -- Receive with start- and end-markers
• Example 4 -- Receiving a single number from the Serial Monitor
• Example 5 -- Receiving and parsing several pieces of data
• Example 6 -- Program to receive binary data

How to process incoming serial data without blocking by @nickgammon

• Example 1: Non-blocking line buffering -- Non-blocking line buffering
• Example 2: Serial parsing state machine -- state-machine for parsing commands. E.g. R4500S80G3

Misc

• Serial parsing RPN/Postfix:
• pcRead by @gcjr -- one-character parsing diagnostic/control tool (w/ Simulation).
• Good Forum thread on parsing a line into tokens with strtok()
• My adaptations of @nickgammon's state-machine parser into a switch-case single-letter post-fix parser for commands and numbers. E.g. 4500R 80S 3G or '123 24 /p`:
  • V1: Simple RPN number and command parsing and
  • V2: RPN 4 function calculator+commands
  • V3: Serial control of Stepper speed, acceleration and motion control with RPN calc -- Use Serial to control a stepper with real-time adjustment of Acceleration, Maximum speed and Position, with 4-function calculator.
• txtZyme (github) with Wokwi sim of txtZyme modified for Stepper Motor

[vayne]

Yes
i should do it on the tinkercad, but they will give me extra point if i did it in real life

[UKHeliBob]

Your duplicate topic has been closed

[TomGeorge]

Hi, @vayne

@vayne

Yes

Why are you being made to use two UNOs?
Is this a school/college/university project?

Thanks.. Tom...

[missdrew]

@vayne

but they will give me extra point

Who are 'they'?
If this is an assignment from an education establishment, 'they' should of aready taught you the skills to do this simple task.