150 LEDs, more problems.

Turns out the Pololu Voltage Booster couldn’t handle the current required and the over current protection was kicking in about twice a second, making the whole circuit flicker. And this was just testing 75 LEDs. I’ve put in an order for another DC-DC voltage booster that can apparently take 3A input. Hopefully this will be able to solve some problems, otherwise I could buy two more Pololus, but then efficiency would decrease a bit more.

Each matrix of 25 LEDs draws approximately 350mA at highest load, thus 6 panels requires an output of 350mA x 6 panels x 5 volts = 10.5W. This doesn’t include the dual Arduinos or the 4 sensors.

The 2000mAh battery is looking a bit short on juice.


Here’s a quick update of what the prototype side looks like.

In continuation from my previous videos - , I’ve arranged the RGB LED’s in a 5x5 square as a prototype for the what-will-be 5x5x6 LED cube. Not much has changed except the layout.

There is a thin plastic layer that acts as a diffuser for the LEDs, and the Arduino is strapped onto the back of the panel.


My delivery from Littlebird Electronics is finally here, and with it, over $150 of sensors and whatnot. Here’s a quick photoset captioned with what each component is, and what role it will play in the final project.

Lessons on Soldering

When I first search on what you need when soldering, one piece of advice stood out: always use a variable temperature soldering iron. I decided not to and suffered the consequences. So, first things first; use a variable temperature soldering iron if you want to avoid tearing your hair out every 5 minutes.

The problem with a fixed temperature iron, and despite the fact that I bought a fairly high-powered one, is that the heat required to solder is relatively precise. If the temperature isn’t high enough, you will have an agonising time trying to melt the solder, and if the temperature is too high, the solder melts quickly into a pool of mess. And it doesn’t help that the temperature varies based on the type of solder, time of day, and the alignment of planets.

And honestly, that’s the only tip you’ll need for a sane time whilst soldering. I initially bought a 40W fixed soldering iron. It started out alright, but soon enough, the solder was a mess to try and work with. Now, with a 40W variable temperature soldering iron borrowed from the School of Art, soldering is painless.

Some quick tips I discovered:

  • Find the ideal temperature first. The solder shouldn’t melt immediately, but also shouldn’t take too long to melt. I have mine set at around 80% power for at 40W iron. You might find that you have to adjust the temperature throughout the session; this is normal as the temperature may vary.
  • Don’t apply solder onto the soldering iron. The solder should be alongside the component/wire that you are trying to solder, and you heat up the solder with the component you are soldering.
  • If possible, apply the solder onto the surface before attaching the component. For my LEDs, I went through each contact and make little solder balls on the contacts first. The second time round, I simply heated the wire on top of the solder and they joined easily. This is especially helpful if you don’t have three hands.
  • Use a continuity checker on the wires after you’re finished to check that you haven’t shorted anything and have made good contacts. You can find a continuity checker on most digital multimeters.
  • Finally, use hot glue over the joints once you’re sure everything works. This prevents wires from touching due to flexing or other movements. It also helps protect other components from contact or sometimes piercing due to some pointy wire at the end. Note that hot glue would be a hassle to remove, so make sure the previous tip is fulfilled first.