Have you ever wanted to learn how to solder and make your own electronic project? Now you can! This is Blinky KEY board, an electronic kit you put together to make your own LED blinking keychain! Everybody can build this project, thanks to these easy to follow, step-by-step instructions I made and a few simple tools. You will learn basic electronic components, and also how to solder to make something useful! The board has 5 bright LEDs that blinks and display various animations! Powered by a single coin cell battery and the popular Atmel Attiny85 chip, you can create your own Arduino code to create your own animations! Oh, and before we start this awesome soldering kit, this is an open-source project, so I will upload the code and the PCB schematics! Of course, you can contact me by email if you want to order a kit from me, as it will support my next ideas and projects! Remember, the 2 first persons to order a kit will receive an additional 20% off the order and a free Blinky KEY board PCB!! Here is my ebay link: https://www.ebay.ca/itm/Blinky-KEY-board-Soldering-kit/183935146954?hash=item2ad3639bca:g:V8YAAOSwbsNdNtUA. **NEW** We have updated the Ebay listing to make it more accessible and convenient, and we are now shipping internationally! You can contact me by email at: firstname.lastname@example.org . Now let’s start!
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Step 1: How It Works
The circuit is based on a small Atmel Attiny85 chip, and the program running inside is based on Arduino. The code is easy to understand, so you can customize it or even create your own! The board is powered by a small CR2032 coin cell battery, that provides 3v. You can always turn off the board because there is a small SPDT on/off switch in the kit. Five 5mm LEDs are used to display the animations, each LED has his own 200 ohms current limiting resistor. The Attiny85 chip is a small and fragile device, so to make sure that the current is stable, I added a few capacitors at the power pins of the chip. Each LED has his own pin on the Attiny chip, so they can be turned on or off independently.
Step 2: Tools You Will Need
You will not need a lot of tools to build this project, so it’s perfect for kids or beginners!
I will list some links to amazon (not affiliated)
Here is a list of tools that are essential:
1. A soldering iron
( A soldering iron is the most important tool of this list, because it will allow us to create the solder joints on the PCB board)
2. Spool of solder
( make sure to use solder intended to be use for electronic projects, NOT for plumbing)
3. A pair of cutters
(A good pair of cutters will work like a charm to cut the legs of the components)
4. Pair of needlenose pliers
5. Helping hand
(Optional, but really useful to hold the board while soldering)
6. Safety Glasses!!
(Really important !!! Safety is really important so make sure to wear some!)
Step 3: Components List
Make sure that you have everything in your kit before starting.
You should have the following:
1x Attiny85 chip (preprogrammed)
1x 8 pin socket for the Attiny85
1x SPDT slide switch
1x Coin cell battery holder
5x 5mm LEDs
5x 200 ohm resistors
1x 0.1uF orange ceramic capacitor
1x 10 uF electrolytic capacitor
1x key ring
1x CR2032 coin cell battery
1x Blinky KEY board printed circuit board (PCB)
Step 4: Let’s Start Soldering! (Part 1. Resistors)
Let’s start soldering!
Turn on your soldering iron, and let’s get started!
1. Place your circuit board on the helping hands or like me, you can use a small vice. ( You can also use none of them, it’s not obligated :)
2. The first components that we need to place are the resistors. They’re location on the board is R1, R2, R3, R4 and R5.
3. Place them trough the PCB holes , and flip the board over.
4. Using a pair of pliers, bend the legs of each resistor as shown.
5. Solder the legs to the board, to do that:
1. Hold your soldering iron with 1 hand, and hold the spool of solder with the other.
2. Place the tip of your hot soldering iron againts the silver pad of the board and the resistor leg, hold it there for 2 seconds (don’t remove the soldering iron after)
3. While the soldering iron tip is in place, put some solder to the soldering iron tip’s and the pad. It should melt and flow on the pad to make a nice chocolate chip looking connection (like on the pictures)
4. If not, try to put your soldering iron and heat the pad again (Be careful because excessive heat could cause damage to the circuit board and component!)
6. Once every resistor’s legs are soldered, trim the excess leads using the wire cutters.
7. Make sure to follow the steps and to look carefully at the pictures before moving on to another step.
Step 5: Part 2. Capacitors
Now we will add 2 capacitors!
Note: there is 2 kinds of capacitors included in this kit, the black cylinder one needs more attention for the installation on the circuit board)
A. We will install the black 10 uF electrolytic capacitor first.
1. This kind of capacitor is polarized, which means that if you put it in the wrong way, it will not work!
2. The capacitor has 2 legs, on is longer, and the other one is shorter. The long leg is the positive (+) lead and the short leg is the negative (-) lead.
3. C2 is the emplacement of this capacitor on the board. On the footprint of the board, there should be a (+) and a (-) marked.
4. Place the LONGEST (+) leg into the (+) on the board and the SHORTEST (-) leg into the (-) on the board.
5. Please double check everything and look at the pictures.
6. Note that there is a white/silver stripe on the side of the capacitor. This stripe should face left, please look at the pictures for reference.
7. Once you are sure that the capacitor is on correctly, you can flip the board over, bend the legs and solder them.
8. Clip the extra leads.
B. We will now install the non-polarized 0.1 uF capacitor.
1. Place the capacitor in place, this one is orange/yellow and you can place it in either way.
2. The emplacement for this one on the board is C1.
3. Flip the board over, bend the leads, solder and clip the extra legs.
Step 6: Part 3. the LEDs
Now lets solder our LED’s
Note: like the capacitor we soldered, LED’s have a polarity too! Same thing as the capacitors, short leg is negative (-) and long leg is positive (+)
1. The emplacements for all 5 LEDs are LED1, LED2, LED3, LED4 and LED5 on the board
2. One side of the LED is flat, and the other side is round, like on the PCB.
3. The flat side is negative (-) and the round side is positive (+)
4. For all 5 LEDs, place the long leg (+) in the round side, and the short leg (-) on the flat side on the board.
5. Please look at the pictures to make sure everything is right.
6. The round side of the LEDs should match with the round side on the PCB board.
7. Once you are sure everything is right, you can flip the board, bend the legs, solder and trim.
Step 7: Part 4. the Switch
Now we will install the on/off switch!
1. The location for the switch on the board is S1
2. Place the switch in place
3. Flip the board over, and solder.
Step 8: Part 5. the DIP Socket
We will now install the 8 pin socker for our Attiny85 chip
Note: Again, this component needs to be installed correctly. Look at the pictures if you are not sure.
1. The emplacement is IC1 on the board
2. Note that there is a little notch on the socket and one the board towards the right.
3. Place the socket in place, make sure that the notch on the socket matches with the notch on the board.
4. Once you are sure everything is right, you can bend 2 legs on the socket, and flip the board over.
4. Solder the socket.
Step 9: Part 6. the Coin Cell Battery Holder
Now it’s time to solder the CR2032 coin cell battery holder
1. Place the holder has shown in the picture
2. Make sure you don’t place it backwards
3. Flip the board over and solder
Step 10: You Are Done Soldering!
Once everything is soldering, the board should look like this:
Step 11: Time to Place the Chip!
We will now install the Attiny85 chip into the socket
1. You will need to pinch the legs of the Attiny85 a little bit before installing it.
2. Like the socket, the chip has a little dot on one side.
!!!! Make sure to locate the little dot on one side of the Attiny85 chip !!!
You will need the match this dot with the little notch on the socket.
!!!please make sure to look at the pictures!!
3. Install the chip correctly in place, if you don’t place it in correctly, you will burn it!
Step 12: Final Step!
Now that everything is soldered, and that the Attiny85 chip is in place, you can add the key ring.
Step 14: Enjoy It!
Now you can add your keys, and show it to your friends! Be proud of yourself!
The LED’s should blink and displays all sorts of animations, but if you want to create your own, you can always modify the code!
Step 15: How You Can Buy the Kit
The kit will arrive to you with all the parts mentioned in the instructions. If you want to buy the kit, please contact me at : email@example.com. You can also order it using my ebay link ;
*NEW** We have updated the ebay link and listing to make it more convenient and easy for people to buy the kits! We are now happy to say that we ship internationally!
Remember, doing so will support me and help me bring more awesome kits and projects on instructables! The first 2 persons to order a kit will receive 20% off and will also get a free Blinky KEY board PCB! Don’t forget that this project is open-source, so you I will publish the code and schematics
Designed and tested in Canada by Antoine Lépine.
Step 16: How to Install the Battery
This project is using a CR2032 coin cell battery. To install it, make sure that the + face on the battery faces up. Use the pictures as a reference :)