Picture of Easy Bluetooth Enabled Door Lock With Arduino + Android
Thanks to everyone who supported this project and voted for it in the Arduino Challenge! I was awarded second prize and hope to participate in more Arduino contests in the near future.

This tutorial will explain a simple way to make a password protected bluetooth door lock using your Arduino, which can be unlocked by sending a four digit pin from your Android phone!  The hardware setup is quite simple,  and the programming side of it is a bit tricky, but should be no problem for any Arduino ameuture.

Step 1: Parts Needed

Picture of Parts Needed
1. Arduino (I am using the Duemilanove)

2. Electric Door Strike

3. Bluetooth Module ($9.99)

4. Power Supply (Required voltage and amperage differs among different door strikes/locks)

5. TIP120 Transistor

6. 1N4001 Diode

7. Hookup Wire

8. Solderless Breadboard

9. An Android phone (optional, considering that there are lots of devices you could use to send serial data to our bluetooth modem including Iphones, computers, and other Bluetooth devices)
1-40 of 133Next »
SabriM made it!8 months ago

Hello guys. I made it as a part of my graduation project. I am building android application too.The logic of the circuit in pics is %98 same with this one. My android application is ready too. I will upload it in few weeks.Images are HD. You can see the circuit clearly. Thanks Collin Amedee. But I changed Arduino code to this one in the link : http://english.cxem.net/arduino/arduino5.php


Hi is this possible to use WIFI + bluetooth to unlock the multiple door ? and if yes what changes ive to made??

SabriM HaziqS19 hours ago

Hi HaziqS,

Sure you can. But you just need to use multiple cable to connect all of them into one source.

IZwadieA SabriM12 days ago

Hello SabriM.

I would like to ask about the output device..can i use electromagnetic door lock instead of electric door strike??

SabriM IZwadieA19 hours ago

Hello IZwadieA,

I just control electric from code. There are two controls about it. Deactive electric from door lock to lock and activate the electric to activate door lock. If your device support this of cource you can.

bigworld21 SabriM3 months ago
hi sir sabri, hmm i m interested with this project,may i see ur full circuit,n ur android apk for control the lock .. pls mail me wellsinclair@gmail.com
SabriM bigworld2119 hours ago

Hi the circuit is just above and developed from this project.

You can download the app from the link below in Play Store :


And Dowload Arduino code from :


Collin Amedee (author)  SabriM3 months ago
Hello SabriM,

I very much appreciate you building onto this project, and especially answering questions whilst I have been inactive over the past several months! I do hope that you received a good grade on your project!

Thanks, and good luck!
nobodykid SabriM5 months ago

hi i'd like to ask about the bluetooth modules. if i'm using different modules, will the codes changes too? if so, which one is likely to be changed, the Arduino or the one in phone? thanks

SabriM nobodykid5 months ago

No I don't think that will change anything. I used HC 06 but you can use HC 05 too.

nobodykid SabriM5 months ago
SabriM nobodykid5 months ago

The code is not about Bluetooth module. It doesn't effect it. You can use it. Differences between Bluetooth modules is about their security.

hi . i want to add this project to my graduation project "advanced easy home security systems"
so can u please send me all the details of this project to this email seda4unit@gmail.com

This is the link of my Term project : Language is Turkish but you can get some details from video. I will try to add English subtitle.


Hi is this possible to use WIFI + bluetooth to unlock the multiple door ? and if yes what changes ive to made??

HaziqS14 days ago
mjgable1 month ago

I had success creating the project by following the steps. I was wondering though... Is there anyway to state the wrong password was entered to let the user know they need to try again?

JayveeA11 month ago

how to insert the code what software is to be use??

JayveeA11 month ago

what software please?

hi,i have to do mini project and its about fire detrector.

The fire will be detected by the sensor then a bluetooth transmiiter will tell my pc which will send sms message via ip to my phone.

please i need your help in connecting the circuit,i dont know the circuit that i should use.

Dhivagar.V5 months ago

how will u change the password using mobile app instead of the password being static as "ABCD"??

hafiizhadis5 months ago
mohit98905 months ago

i want the project details for my seminar can u mail me at mbhanushali5@gmail.com

saeedbayat7 months ago

hi .who help me to make this project?

saeedbayat7 months ago

hi .who help me to make this project?

saeedbayat7 months ago

hi .who help me to make this project?

pelegren7 months ago

it won't work with arduino nano v3 and HC-06. help please.....

Skaedryn7 months ago

Might want to add a failsafe?

oh_mali made it!11 months ago

Hi, here are some pictures and personal notes from my finished version of this project!

1) Make sure that you buy the CZ-HC-05 Bluetooth module as well. Some people will advertise the carrier board & the Bluetooth and sell only the carrier board (part label JY-MCU) without the actual Bluetooth module (CZ-HC-05) soldered onto it.

2) I also found a helpful link (HERE: http://www.instructables.com/id/Modify-The-HC-05-Bluetooth-Module-Defaults-Using-A/?ALLSTEPS) on how to reset mostly anything you need via AT Commands through the KEY pin on the Bluetooth.

3) Instead of an electric door strike, I used a door lock made active/inactive by a solenoid that works on 12V (because it was much cheaper at $20 rather than $100+!!)

4) I used the Arduino Uno board instead and it works just the same.

5) If the Bluetooth SPP app you're using counts the /r as another byte, you'll have to change the first for condition in the void looping section from 4 to 5. ( for(int i=0, i<5, i++) )


SabriM oh_mali8 months ago

Hi I have bought HC06 bluetooth module. Is it not going to work for this project? Why make sure HC05? Thanks.

oh_mali SabriM8 months ago


Your module will work for this application.

In my original post I was saying to make sure that you order the actual chip in addition to the carrier board, rather than just the carrier board.

Both modules have the same hardware, but different firmware. The HC-06 is a slave device, i.e. it can't start the communication (this process is know as pairing in bluetooth jargon) with another device, it needs a master (PC/Smartphone) that pairs with it. On the other hand, the HC-05 is a master/slave device, i.e. it's capable of peer to peer communication with other HC-05 modules, it can be the master of an HC-06 module, it can be a slave of a PC/Smartphone, etc.

If need be, more can be read HERE:http://embeddedprogrammer.blogspot.com/2012/06/ubuntu-hacking-hc-06-bluetooth-module.html

SabriM oh_mali8 months ago

Thanks. oh_mali . I made it :) . I am building android application too. Application is ready too. I ll upload it to store in few weeks.

tiongson1 year ago

where is the connections of the electric door strike ???????

SabriM tiongson8 months ago

Its step 3. Lock - and +

ekeesee9 months ago

Could you draw up some wiring instructions or take a couple other pictures of the setup?

SabriM9 months ago

Does it send feedback if someone else already opened or locked the door? For instance I locked it from android device and then someone else unlocked it by his hands. Will I be able to see feedback on android device that lock has been unlocked?

skalra210 months ago
instead of using direct power supply for lock, can i take it via Vin pin of arduino uno, my solenoid lock requires 12v dc and 0.6A for its operation.
oh_mali11 year ago

Can you post a parts list detailing your vendors and part #s?


randersen61 year ago
How do you open the door during a power outage ?
1-40 of 133Next »