Difference between revisions of "Art Controller Hardware Variations"

Revision as of 00:46, 12 September 2012

This page, part of the documentation for the Art Controller kit, lists some possible modifications that you might consider when assembling and using your kit.

Some of these potential modifications can save you assembly time (by skipping unneeded components) or otherwise help you to fine-tune or repurpose your Art Controller.

Terminal Blocks:

Any of the three terminal blocks can be left uninstalled if you would prefer to hard-wire (solder in) the connections there, or if they are otherwise not needed.

The output terminal block (J3) can be omitted if:

• You want to hard-wire your load to location J3 by soldering wires into that location on the circuit board.

The DC power input terminal block (J1) can be omitted if:

• You are using a DC input barrel jack (at location J5) to connect to a power supply, and do not plan to use the terminal block.
• You are planning to feed 5 V power to the board through the ISP header, J4, or through the +5 V port near U1.
• You want to hard-wire your DC power to J1 by soldering two wires into that location on the circuit board.

The trigger input terminal block (J2) can be omitted if:

• You want to hard-wire your trigger input signals to J2 by soldering two wires into that location on the circuit board.
• You do not need a trigger input, for example if you are only using the Trigger @ Reset option, or if you have reprogrammed the Art Controller for different behavior

DIP Switches:

The Art Controller kit comes with an 8-position DIP switch to set timing.

You may wish to omit this DIP switch:

• To semi-permanently configure a particular timing option.
• To leave available the corresponding 8 lines on the microcontroller as general-purpose I/O lines, if you are reprogramming the micrcontroller.

If you are assembling many Art Controller units, each with the same timing, it may be faster to install a jumper wire or two on each board, say to configure each for a 15-minute delay, than to insert and solder each pin of the DIP switch.

DC Power:

Using the voltage regulator
The Art Controller requires DC power to operate the microcontroller and relay. It features an on-board linear voltage regulator and accepts input power in the range of 7-15 V DC. (A 9 V or 12 V DC power supply will work nicely.) The regulator steps the voltage down to 5 V, so that the microcontroller and relay can use it. There is a location, next to U1, where you can tap off a very small amount of 5 V power (say, 25 mA) if needed. The amount of 5 V power that you can generate is limited by power dissipation; the regulator will overheat if you draw too much excess 5 V current.

Omitting the voltage regulator
If you prefer, it is also possible to instead configure the Art Controller to operate directly from a regulated 5 V DC power supply by omitting the regulator during assembly. To do this, omit the regulator U1 and instead solder a wire between pins 1 and 3 (the outer two pins) of U1. A good wire choice for this would be the clipped lead from one of the diodes. Take care to ensure that the wire between pins 1 and 3 cannot touch pin 2; that would cause a short circuit. Capacitors C1 and C2. can optionally be omitted as well with this modification.

With the regulator removed in this way, you can apply regulated 5 V DC power to either the DC power terminal block, to the optional barrel jack location, or to the +5 V port by U1. However, take note that the board will no longer be tolerant of higher input voltage.

As a third option, +5 V DC and Ground are broken out on the ISP programming header, J4, and can be tapped off there if necessary.

Programming Header:

The programming header, J4, can be omitted if you do not plan to reprogram the board. The lines going to this header include +5V, ground, reset, and three additional I/O pins. Refer to the schematic for additional detail.

Skipping the Relay:

In some circumstances, it may be desirable to omit the relay itself from the Art Controller. The relay coil is normally driven by a transistor. You can instead use that transistor to drive a smaller DC load in place of the coil.

Reducing Power Consumption:

Typical power consumption of the Art Controller, built according to the instructions is approximately 95 mA when the coil is energized and 13 mA when idle.

A non-negligible fraction of the power consumption is actually from the two LEDs. The two LEDs indicate power and when the coil is energized. However, you can simply not install one or both of them without ill effect (other than the obvious one of not having those two indicators there to look at. If you have already installed the LEDs, you may find it easier to clip resistors R1 and R3, rather than to desolder the LEDs.

Operating in the Dark:

As noted above (under "Reducing Power Consumption"), one or both LEDs can be disabled or simply not installed if it is helpful for the Art Controller to not emit any light.