Make Heart v2.0

Making the Heart

Being that there are a number of resources online about how to solder. I am not going to go over that here. This is a fairly straight forward kit that should be a great first time project. If you haven’t soldered before I suggest you check out this page for a ton of examples and links. It’s actually how I learned to solder, by reading, watching, and then practicing.

Document Map:

Overview
Step 1: The Parts
Step 2: Soldering the LEDs
Step 3: The Resistors
Step 4: The Headers and Cable

What you will need to build this kit:

  • Soldering Iron (a cheap one will work, but a temperature controlled iron will improve your soldering)
  • Flush Cutters
  • Solder
  • An Arduino (covered in the programming portion)

Things you really should have, but do not absolutely need:

  • Helping hands
  • De-soldering braid
  • Multimeter

I suggest you check out this list of recommended items for a good soldering setup. I’ve also written up a blog post for workshop setups, but this can easily apply to someone on a budget.

Some tips before we start:

  • Lay out everything beforehand, and go through the directions at least once before you start.
  • Keep your iron tip clean. I Highly recommend a brass tip cleaner.
  • Use 60/40 flux core electrical solder, unless you have a good iron and know what you are doing.
  • The joints should look like a “Hershey’s Kiss”, completely covering the pad.
  • Do not over-heat things. It will only take 1-3 seconds at the most to solder a joint.
  • Don’t abuse your tools. Use your tools for their intended purpose, and keep them maintained. This will dramatically improve the quality of anything you do.
  • Double check your work.
  • If you get stuck, don’t be afraid to ask questions.
  • Check out the Flickr set of the version 1 Open Heart for a ton of additional information.

Step 1: The Parts

Check your kit and make sure you have all the parts you need. Click on the images for details:

Open Heart v2 02 Your kit should contain:

  • 1 Open Heart v2.0 PCB
  • 1 Cable
  • 28 Red LEDs
  • 6 100 ohm resistors
  • 1 Straight 6-pin header
  • 1 Right-angle 6-pin header

If you have one of the older v1.1 kits, you should go here for those instructions.

Step2: Soldering the LEDs

Open Heart v2 06 Since the LEDs are diodes (light emitting diodes), they go in just one direction. The purpose of a diode is to help direct the flow of electrons so that they go where you want them. The LEDs happen to emit light while doing this. That principal is also what allows us to light up so many LEDs with so few pins of the Arduino. There are actually two markers for the LEDs that allow us to tell their polarity. The first is that the long lead is positive, and the short lead is negative. You can also see above that a small notch is taken out of the LED case, that marks the negative side as well.

Open Heart v2 04 If you look at the silkscreen (the white markings) on the PCB (printed circuit board), you will find that a little notch has been taken out of the LED drawing as well. You are going to be placing all of the LEDs in the same way, matching both the notch and short lead to the marked spot on the PCB.

Open Heart v2 07 It’s much quicker if you do these in columns. So go ahead and pick a column and place all of the LEDs in, making sure to pay attention to the orientation that the LEDs are going in.

Open Heart v2 08 This is advantageous for many reasons, but one of the best is that you can quickly tell at a glance that all of your LEDs are in the same direction.

Open Heart v2 09 I like to slightly bend out the leads of the LEDs to keep them in place while soldering. It helps to push against the LED while you do this, so that it lays flush with the PCB.

Open Heart v2 10 Go ahead and solder one lead for each of the LEDs down the column. I only do one for each, because this is where I like to straighten the LEDs up.

Open Heart v2 11 With only one lead soldered into place, you’ll only have to heat one joint to straighten up the LED. By simply pushing against the LED while you heat the solder joint, it should lay flat against the PCB. When they are all flat against the PCB, they should line up perfectly with little work. Since this kit is meant to be shown off, a little extra time here is well worth it. There is a picture in the v1.o set that shows the process.

Open Heart v2 12 Once you are comfortable with how straight the LEDs are, go ahead and solder in the rest of the leads. Then clip them fairly short. NOTE: keep a finger on the leads as you clip them, as the like to fly off into all kinds of places (like eyes). You can now continue on as you like, the following pictures are simply some examples of possible ways to proceed. Once you are done with the LEDs, you can skip ahead to the resistors.

Open Heart v2 13 I tend to do opposite columns, so that the PCB sits a bit flatter against a table.

Open Heart v2 15 I also like to do two or three columns at a time. This can really help speed up the process straightening the LEDs, because it gives you more of a reference.

Open Heart v2 18 Keep filling in columns.

Open Heart v2 19 Eventually they will all be in. Hopefully you’ve been straightening them the whole time, and they are all lined up. Next we will be soldering in the resistors.

Step 3: The Resistors

Open Heart v2 20 Unlike the LEDs, the resistors can go in any way. An easy way to bend them into the shown shape, is to just use your finger. You hold onto the middle part, and simply push the lead over about 90 degrees, then do the other side. If you get the spacing right, the resistor will slide right in. You can go ahead and put all of them in at once if you like.

Open Heart v2 21

You want to make sure that the resistors sit flat against the PCB, and slightly bend out the leads.

Open Heart v2 22 There is plenty of space to work around the resistors. So go ahead and solder them into place, clip the leads, and you are done. Now it’s time to move onto the headers.

Step 4: The Headers and Cable

Now you have to make a decision, and you have three options. Each has it’s own advantages.

No Headers:
I’ve designed this kit to be sew-able. So all of the circular pads around the heart are all conductive. That means that you can simply use some conductive thread to connect the heart to a lilypad Arduino. If that is what you are doing with this kit, then you are done, and can move onto programming!

Straight Headers:
The straight headers are great if you just want to simply plug the heart into the Arduino, or alternately soldering it into a breadboard type project. I generally solder the straight headers in for ease of use in projects.

Right Angle Headers:
The right angle headers are great if you want to wear the heart without having to sew it into something permanently. I generally wear the heart around with the right angle headers going through my shirt, and the cable connecting from the other side. You can then run the cable around to something like an Altoid’s tin with an Arduino in it.

Open Heart v2 23

If you are soldering either of the headers onto the board, I would suggest using the cable to hold it into place. You can simply solder one joint in to roughly hold it into place.

Open Heart v2 24 While applying a bit of pressure, head the single joint and try to move the header to an angle that you like.

Open Heart V2.0 Congratulations, you should be done, and now it’s on to programming!