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Build a Mintronics: MintDuino

Learn how to make an Arduino compatible microcontroller circuit on a breadboard.

Build a Mintronics: MintDuino

The MintDuino is perfect for anyone interested in learning (or teaching) the fundamentals of how microcontrollers work. It will have you building your own microcontroller from scratch on a breadboard, and then easily programming it from almost any computer via the Arduino programming environment.

Unlike pre-built microcontrollers, the MintDuino demonstrates the specific relationship between the wires, resistors, capacitors, and integrated circuits that enables you to program the microcontroller from your computer. After building the MintDuino, you’ll have a much better understanding of how microcontrollers work, and how electronics can interact with the physical world.

Steps

Step #1:

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Build a Mintronics: MintDuino
  • Start building your MintDuino by adding the 7805 power regulator. This converts the 9v power to 5v power that the ATMega can use.
  • Insert the 7805 into column "i" on the breadboard and rows 1,2 & 3 as pictured. The metal heatsink should be facing the right (or column "J")

Step #2:

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  • Now we are going to add one 10 uF capacitor to the power regulator.
  • I like to trim the leads down so it doesn't stick so far out of the breadboard. One lead is longer than the other. The long lead is the (+) lead and the short one is the (-) lead. If you trim it, make sure to keep the lengths different lengths so it's easy to identify the (+) and (-) leads.
  • Insert the (+) lead into "g1" & the negative lead into "g2". Easy!

Step #3:

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Build a Mintronics: MintDuino
  • Next is the other 10 uF capacitor that we use to smooth out the power on the breadboard.
  • Insert the (-) lead into row 1 of the (-) power rail of the breadboard.
  • Insert the (+) lead into row 1 of the (+) rail of the breadboard as pictured.

Step #4:

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  • Now let's get some regulated power over to the power rails of the breadboard.
  • Start by stripping the ends of one piece of red wire cut to approximately 1/2" long. Insert the wire from the (+) rail of the breadboard to "j3" of the breadboard.
  • Next strip the ends of one piece of black wire cut to approximately 1/2" long. Insert the wire from the (-) rail of the breadboard to "j2" of the breadboard as pictured.

Step #5:

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  • Now we are going to add the power LED (Red).
  • Start by cutting down the leads, as we did on the capacitor. Make sure to keep the long one (+), long, and the short one (-), short!
  • Now you can insert the red LED into the breadboard.
  • The longer lead (+) goes into "d2" and the negative (-) goes into "d1"

Step #6:

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  • Let's get the power distributed around the board and to the LED.
  • Start by cutting one red wire, approximately 1/2" long and one black wire, approximately 1/2" long. Strip both ends of each wire.
  • Insert the red wire from "f1" to "e4", and the black wire from "f2" to "e5".
  • Cut another piece of black wire about 1/2" long (I'm going to stop saying "strip each end" each time) and insert it from the (-) rail of the breadboard (picture 2) and "b1"
  • While we are here, lets add a 220Ω resistor (red, red, brown) from the (+) rail of the breadboard to "b2".
  • Lastly, cut one piece each of red and black wire about 1 1/2" long and connect the right side rails together. Remember to connect (+) to (+) and (-) to (-) as in picture 3.

Step #7:

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  • Power it up!
  • Now connect the battery clip's red wire (+) to "d4" and the black wire (-) to "d5".
  • Connect a 9v battery and the red LED should light up.
  • If not, immediately unplug the power and double check everything!!!
  • Now you have a nice 5V regulated power supply from a 9V battery. Your ATMega will thank you for it!
  • OK, enough fun. Unplug the battery and let's get started with the micro controller.

Step #8:

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  • Now it's time to hook up the ATMega 328.
  • Did you unplug the battery? Yes? Good! Let's get started.
  • The ATMega has a small "U"-shaped notch on one end. This notch lets you know where pin 1 is on the integrated circuit (IC) or "chip". If you hold the chip vertically, with the notch on top, pin 1 is directly to the left of this notch.
  • Insert the IC so the notch is towards the power supply we already built.
  • Insert pin 1 into "e9" as pictured.
  • You may need to bend the pins in a little bit so they don't flare out too much. You shouldn't need a lot of force to insert the IC.

Step #9:

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  • Time to add the crystal.
  • The crystal is inserted into the breadboard at "b17" & "b18". Orientation isn't important; either way is fine.
  • The crystal needs some capacitors to work properly. The two 22pF capacitors are not polarized, so orientation does not matter.
  • Use one 22 pF capacitor (marked 220) and insert it into the the ground rail of the breadboard and "a17".
  • The other 22 pF capacitor (marked 220) is inserted into the the ground rail of the breadboard and "a18".
  • While we are here, cut a 1/2" piece of black wire and connect the ground rail of the breadboard to "a16".

Step #10:

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  • Time for more power!
  • Cut 3 pieces of red wire, all of them about 1/2" in length, and one black wire 1/2" in length.
  • Use one red wire to connect the (+) rail of the breadboard to "j16"
  • Use another piece of red wire to connect the (+) rail of the breadboard to "j17"
  • Use one black wire to connect the (-) rail of the breadboard to "j15"
  • Back to the other side of the board (by the crystal). Connect the remaining red wire from the (+) rail to "a15".

Step #11:

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  • Now let's wire up a status LED. This will help us know everything is working properly.
  • You can trim the LEDs leads if you prefer; also cut one piece or red wire about 3/4" long.
  • Insert the longer lead of the LED (+) into "i24" and the shorter lead (-) into "i25".
  • Next connect the (-) ground rail of the breadboard to "j25" using a 220Ω resistor (red, red, brown).
  • Last but not least, connect the "h24" to "h18" with the red wire as in picture 3.
  • Now you have an LED connected to "pin 13" of the "Arduino". It's actually not pin 13 of the ATMega. The Arduino IDE uses different definitions for the pins to simplify its use. I'll go over the pins in the last step of the build.

Step #12:

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  • Time for another test.
  • Go ahead and reconnect the battery (see step 7).
  • The red power LED should light up immediately, followed by the green LED. The green LED will blink. This is because a simple blink program has already been uploaded to the ATMega.
  • If the LEDs don't light up, immediately disconnect the power, and check all you connections again.
  • But how do you program it? That's next!

Step #13:

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  • Adding the reset button.
  • Cut one piece of black wire about 1" in length.
  • Connect the ground rail (-) of the breadboard to "d6".
  • Cut another piece of black wire about 1/2" in lenght and connect it from "d8" to pin "1" of the ATMega at "c9"
  • Now press the button into the breadboard. It only fits 1 way, so make sure the pins all line up properly. The four leads of the button will fit in "e6", "e8" & "f6" & "f8".
  • The last step is to connect "b9" to the (+) rail of the breadboard with a 10kΩ resistor (brown, black, orange).

Step #14:

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  • Wiring the programming pins.
  • Start by using a pair of pliers to adjust the pins (gently) to be centered in the plastic rail.
  • In picture 2, you can see the 3 pins on the right are perfect. The 3 pins on the left still need to move down a bit.
  • By centering the pins it makes it much easier to plug in the FTDI adapter later.
  • Once they are centered, insert the 6 pins in column "b" from "b25 - b30" as pictured.

Step #15:

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  • Now we need to wire up the programming pins.
  • Cut three lengths of green wire (color may vary) approximately 2" each.
  • Use one wire to connect "d10" to e27"
  • Use one wire to connect "c11" to "d26".

Step #16:

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  • Use one green wire to connect "d9" to "c23"
  • It's a little hard to see. Make sure to double check all the wires.
  • Next, add the 100nF capacitor (marked 104 on one side and K1K on the other) from "c25" to b23". It is not polarized, so inserted either way is fine.
  • The final step is to add a 1/2" piece of black wire from "a30" to the ground rail (-) of the breadboard.
  • All done! Now you can start programming the ATMega!

Step #17:

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  • To program your new MintDuino you need a USB -> serial connection.
  • We suggest you use an FTDI Friend, but most FTDI cables will work.
  • The FTDI friend can be purchased at the Maker Shed.
  • Does anyone else think it looks like a scorpion?

Step #18:

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Here are some labels to show you the ATMega pins (left) and the "Arduino" pins (right).


Comments

  1. Marc de Vinck says:

    (1) ATmega328P (with Arduino bootloader)
    (1) Mint Tin
    (1) 1/2 size breadboard
    (1) 7805 Voltage regulator
    (1) 5mm LED Green
    (1) 5mm LED Red
    (2) 220 Ohm resistors
    (1) 10k Ohm resistor
    (2) 10 uF capacitors
    (1) .1uF capacitor
    (1) 16 MHz clock crystal
    (2) 22 pF capacitors
    (1) 100nF capacitor
    (1) Momentary normally open button
    (1) 6-pin male header
    (1) 9V battery clip with leads
    (3) 12″ – 22 AWG solid core wire

  2. Marc de Vinck says:

    It is pin 13 of the “Arduino”, which uses a different pin layout from the ATMega. It’s pin 19 of the ATMega. I added a PDF of the pin layouts for clarification.

  3. Marc de Vinck says:

    I added the parts list to the comment above, and will add them to the Make: Projects page soon. Thanks!

  4. Marc de Vinck says:

    The FTDI friend gets plugged in so the “black” or GND of the FTDI is towards the bottom of the board (30b). You can see the wire that jumps to ground.

    In the Arduino IDE select the proper com port for the FTDI (usually the first one listed, but no always), followed by a board type of “Arduino Duemilanove w/ATmega328″

    More tutorials coming soon! (I just finished reading one and it’s great)

  5. Marc de Vinck says:

    Step 16 (Take a look at the second image for placement)

    “Next, add the 100nF capacitor (marked 104 on one side and K1K on the other) from “c25″ to b23″. It is not polarized, so inserted either way is fine.”

  6. tickduck999 says:

    Ok, we bought the 100nF capacitor so we won’t need the 1uF which I interpreted as 1 micro Farad.
    Do we then need two 100nF capacitors?

    Mentioned in partlist:

    (1) .1uF capacitor

    (1) 100nF capacitor

  7. tickduck999 says:

    There you make a simple guide for all of those who don’t understand anything about electricity and just won’t mention that 100nF is the same thing as 1uF.

    Thanks for nothing.

    If you want to do something that really EVERYBODY can understand, do it properly or don’t do it at all. Or put something like “10 years practical experience as electrician needed” to the top of the page!

    And to answer my own question: No, you don’t need two 100nF capacitors, you just need one. So there only is a mistake in the partlist as asumed from the start.

  8. Robert Porter says:

    @tickduck999 – having a bad day?

    BTW, you said “100nF is the same thing as 1uF” … no it’s not. 100nF is the same as 0.1uF which is what you meant to say. Looks like you’re capable of mistakes as well. By your own rule, “don’t do it at all”.

  9. Ryan Porter says:

    Whoops, I fixed it! I went through the steps again and when I was finished it works now!!! :D

  10. Wesley says:

    Okay, i found what was wrong, but don’t know how to fix it. I was missing a 104 capacitor, and found out that i had used it, in the place of a 220 capacitor. I do not have another 220 capacitor anywhere. I guess it was supposed to come in the kit…?

    1. Hellz Wells says:

      I know this is old, but it sounds like you’re still a bit confused about the components…and maybe a bit of clarification will help others. The kit should include two 22(pF) caps and two 220-ohm resistors, but no “220″ caps. There should be one 104 cap, and just to reiterate the conclusions of other commenters about the error in the above parts list… 100pF and 0.1uF capacitor both refer to the same “104″ cap. It’s just two ways of saying the same thing… 0.1uF = 100pF = 100,000nF (104 marking on cap means 10 followed by 4 zeroes…ie 100,000nF)

      1. Hellz Wells says:

        Oh Ive mixed up my darn metric unit prefixes again….in the comment above when I refer to nF (nanoFarad) it should actually be pF (picoFarad), and vice versa.

  11. Gerry says:

    My son just built this and both lights stay on, the green doesn’t blink. Can someone help and let me know what he possibly did wrong, if anything. The instructions say it’s already set to blink?

  12. Gerry says:

    anyone have an idea what we did wrong? We are new at this.

  13. Raife says:

    Where can I get a schematic of the circuit? Did I miss it? I have been working in electronics for decades, and I really need/desire a schematic for any real level of comfort when building any circuit.

  14. benjamin little says:

    ok where do I get either my money back or an exchange? I have followed the steps in building this many times and it has never worked. There is something fundamentally wrong here.

  15. Kenneth elston says:

    Maybe the kit parts was upgraded or something; but my build worked perfectly the first go around. I am also new at this and thought that this would be a fun build for my first circuit on a breadboard. The only question I have now is WHAT’S NEXT?? Now that I’ve built the thing and the green LED is blinking, what else can I do with it? Where are the tutorials? I even got it connected to my computer using USB!!! Thanks in advance for any information anyone can provide to help me further my education with this build.

  16. Kenneth elston says:

    Also, if possible and if available, could someone point me in the right direction to get the Eagle files for the schematic of this circuit? Thanks in advance

  17. tn8 says:

    At step 12, green LED doesn’t lit or blink… something wrong?

    1. Nick Normal says:

      TN8 are you still having troubles? I just built the MintDuino today (and many times before) and Step 12 blinks fine for me.

  18. Hellz Wells says:

    18 Steps? Is it too much to ask for a flippin circuit diagram?

    1. David Gari says:

      Agreed. Schematic diagrams are ESSENTIAL for any circuit more complicated than a flashlight. One schematic is worth 1000 pictures of a breadboard covered in parts and wires.

      It is foolish with a capital F not to include one.

      1. Raife says:

        As I implied before, schematics aren’t just a good idea, the simple fact is that they are the core, and life’s-blood, of any serious tinkering with electronics. I believe that “Makers” are trying to make such projects less intimidating… Heck, I even… accidentally… purchased one entire Arduino-project book that doesn’t have one single schematic in it (beyond interesting ideas for the Arduino, I consider the book to be almost worthless).

        In my opinion (as a technology-instructor, with years of experience teaching everyone from novices, to engineers) this notion of working with electronics, without the fundamental element of dealing with (and reaping the enormous benefits of) schematics… is truly a disastrous idea.

        Oh… And, I would suggest that anyone building the “Mintduino kit”… “Google Image” search “Mintduino schematic”… for their own sanity (I easily found several, and it saved hours of frustration).

  19. spylerose says:

    Its paint by #. Scematik is not nesesery.its an 18 project for the sake of pet! You know am exersis…….!

  20. […] to both making and learning. First, the circuit is prototyped on a breadboard following the classic MintDuino how-to. After flashing the microcontroller with our Pulse Sensor compatible code, the entire circuit will […]

  21. bob says:

    Got one of these today and assembled fairly quick. Wish I would’ve known to pick up an FTDi friend as well… Off to google a way to program this with whatever I have around here.

  22. Caleb Cook says:

    I am still not sure how to program this. I have a FTDI friend, but then what do I do?

  23. nathan esterkyn says:

    what board should I specify this as in the arduino ide, and what programmer

  24. Martin Boroff says:

    I could use some help. I am stuck on step #7 and can not get the red led to light.
    I have triple checked the steps. I have double checked the led lighs on a 3 volt button cel. I have check the resistor for the correct value of 220 ohms. I have checked point to point wiring with an ohm meter for zero ohms. I have checked the voltage going into the regulator at 9 volts and output at 5 volts.

    Any suggestions?

  25. […] Build your own breadboard Arduino (based on Mintduino) […]