VReg? Expansion board? What the heck do I need?

Start with a Base Board

The base boards contain the brain (tiny computer) that decodes the MIDI messages from your PC. It also contains enough power switching circuitry to drive up to two skulls.

If you just have one skull (or two), all you need is a single base board. But which one? There are two different ones...

Standard vs. VReg

These two boards do the exact same thing. The difference between the two has to do with what you're using to power them with.

Which one you should choose is determined by the voltage required by the motor, etc. in the skull you are modifying. An easy way to tell is by counting the batteries it takes. Each AA (or C or D) battery supplies 1.5 volts. Here are some common configurations:

• 2 AA batteries: 3 Volts (MYS not recommended)
• 3 AA batteries: 4.5 Volts (choose MYS)
• 4 AA batteries: 6 Volts (choose MYS)
• 5 AA batteries: 7.5 Volts (choose MYS VReg)
• 6 AA batteries: 9 Volts (choose MYS VReg)
• 1 9-Volt battery: 9 Volts (choose MYS VReg)

The reason for this is that the computer on the MYS board requires about 5 volts to operate. For 4.5 - 6 volt skulls it can take its power directly from the skull's power supply. Any higher than that and the computer's voltage needs to be regulated; the VREG version makes sure the computer runs at 5 volts and the motors & LEDs it's controlling are sent the full power supply voltage.

What if I Have 2 Skulls?

One single base board can drive 2 skulls. See above to choose between standard and VReg for your base board.

What if I Have More Skulls?

This is where the expansion boards come in. The base board has the brains to control up to 6 skulls (12 channels since there's one eye and one mouth per skull), but only power switching circuitry for 2 skulls (4 channels). In order to add more power switching channels to a base board, you can get expansion boards.

Each expansion board adds power switching for 2 additional skulls (4 channels). Each base board can be expanded with a maximum of 2 expansion boards (6 skulls, 12 channels).

Less Words, Please

Okay, here's a handy chart.

No. of Skulls	No. of Base Boards	No. of Expansion Boards
1	1	0
2	1	0
3	1	1
4	1	1
5	1	2
6	1	2

What if I Have More Than 6 Skulls?

Then I want to come over and see what awesomeness you're building!

Also, you need a new base board for each 6 skulls. Each group of up to 6 is a separate system. For instance, if you have 10 skulls, think of it like a group of 6 and a group of 4.