0 USB Pinouts

Additional note: As of Battery Charging Specification 1.2 which was released in December of 2010, USB ports can provide current to charging devices drawing 1.5 A with a maximum current of 5 A.

Detail: USB Pinouts

0 Use an IDE cable for Mounting Arduinos

Everybody has plenty of extra IDE cables just laying around, if not have five of mine. Now its time to put them to good use for mounting some of those smaller Arduino boards that have pins on the bottom for bread boarding and such.

This is a convent trick I have been using which allows you to securely mount one of these boards when you pass the bread boarding stage and decide to just stick the Arduino somewhere for a while. I have found that the IDE cables make the perfect platform for mounting smaller Arduinos on. Even better, some of the smaller IDE cables that are used to connect floppy disk drives have almost the exact number of matching pins. The only think that you have to figure out is where each wire in the ribbon cable connects to because there is two rows in the socket, nothing that a bit of testing with a multimeter cant determine!

Detail: Use an IDE cable for Mounting Arduinos

0 Hardware Arrangement

Today I cleaned up the robot's wiring by moving the robot's router and two Arduinos to the front cavity in the robot's chest. To do this I had to replace the plywood piece that was behind the robot's computer with a thinner piece of luan. The move centralizes electronic components and eliminates several feet of wires which now take up only a few inches. The only disadvantage is that this places the robot's most vital components in a vulnerable location; as a solution I plan on making a protective cage that will fit over them. The cage will both act as a Faraday cage as well as a protective enclosure to prevent objects from contacting the electronic components.

Detail: Hardware Arrangement

0 Tips on Soldering

These are just some tips for when you solder electronics.

1. Replace tip if necessary - I don't do this very often but some cheap soldering irons can ware out over only a few weeks of use. You will know if you need to replace your tip because it will look disfigured almost like it melted.
2. Clean the tip with a sponge - do this while the soldering iron is hot. Simply use a damp sponge to wipe  away any carbon (black) and excess solder. The result will be a nice shiny tip.
3. Soldering paste or flux can be used to help solder attach to some surfaces but this is not always necessary.
4. Make sure you are using good solder. Some solder contains impurities and may not bond well to the materials that you are using. I have had good luck with 60/40.

Do and Don't:

• Do: Good solder joint (shiny, smooth)
• Don't: Bad solder joint (dull, lumpy)

Detail: Tips on Soldering

0 Using plugs

Plugs are a great way to make components easy to connect and disconnect. This can save a lot of time when assembling robots because it reduces work of undoing permanent connections in order to modify some parto of your project.

Here is a quick tip for robotics and electronics projects when using plugs.

Electronics tip:

Always connect the female plug (one with receptacles for the pins) to the battery side of the connection.

If you follow this method you help to prevent a short circuit if your connection ever comes unplugged. You also help to reduce the risk of electrocution if you are working high voltages.

Detail: Using plugs

0 Audio jack pinout

I used this pinout when I was working on building my original audio amplifier for the robot. I just figured it might be a good idea to share the image in case anyone else was looking to do the same.

Also, a good trick you can use if you want to convert stereo into mono like I did for the robot's speaker you can simply connect the left and right wires leading to the speaker.

Detail: Audio jack pinout

0 Preventing Shorts When Using Arduino Ethernet Shield

I discovered this a while ago but I thought it would be important to share in case anyone is working on a project using an Arduino Ethernet shield. Most shields connect directly to the arduino board using the standard cascading pin system. The Ethernet shield like many others has the cascading pin feature but what it does not account for is the fact that the Ethernet jack on the board stands higher than the rest of the female pins. I have tried attaching boards above the Ethernet shield and the bottom of the board ends up contacting the metal on the top of the jack. This results in a short circuit if the problem is not noticed before the boards are powered up.

As a quick and easy solution all you have to do to prevent this is place a piece of tape or insulated adhesive over the metal Ethernet jack. This prevents shorts even if another board is directly contacting the jack.

Detail: Preventing Shorts When Using Arduino Ethernet Shield

0 Modular Laptop Removal

As the robot's design has evolved over time one of the most important things I have found is that by making parts modular I can easily remove them and reconnect them somewhere else. Following along with this pattern I have installed a plug that allows me to disconnect the robot's computer from the relay that turns it on. I ran into issues several times before making this fix so now it is a bit more convenient.

New plug to enable easy removal of robot's computer

Detail: Modular Laptop Removal