Wednesday, June 13, 2012

Costume-friendly remote for prop control

I've moved away from using motion sensors to trigger props for several reasons: Some props are too scary for really young trick-or-treaters, motion sensors don't know if the person is looking at the prop or which direction they are walking, and manual operation results in better timing.

However, the buttons on most remote controls are too small for a costumed operator. My werewolf claws can't tell if they are on the button.

Costume Remote Fail

Additionally, the battery life and effective range of the remotes I've tried is less than ideal.

So I set out to design a remote control that is more costume-friendly.

My requirements:
  • Large buttons
  • Control multiple devices
  • Long battery life
First I needed to select a control system. I decided to go with Smarthome's INSTEON technology. A remote can control multiple devices, and "dual band" modules (such as the InlineLinc 2475SDB) receive their control signals wirelessly. The RemoteLinc2 can control 4-8 devices and is the size of a small stack of business cards.

Next, the physical interface. I decided on a black PVC tube, with a large selector knob on one end and a large activation button on the other end. The selector knob will set the operating mode (OFF/1/2/3/4/PROGRAM) and the large button does whatever the current operating mode is set to.

However, I need a way to determine what the current operating mode is, in the dark, without rotating the knob back to OFF and counting clicks forward. I decided to include a 7-segment LED behind a red lens to show the current device number (or a period when in PROGRAM mode)

In order for the selector switch to control power, device selection, program mode and 7-segment LED digits, it needs to be a "four pole" rotary switch. Although the RemoteLinc2 supports 8 devices, I decided 4 was enough. 4 plus OFF and PROGRAM means the selector switch needs 6 positions, so it needs to be a "four pole six throw" (4P6T) rotary switch.

Newark sells one made by Electroswitch that is quite well made. Part number is C4D0406S-A. It was a special order. This is the "shorting" type rather than the "non-shorting" type. Shorting, or "make before break" is requried since one of the four poles carries power to the InlineLinc and it needs to stay ON between mode changes 2-6 (1-4 plus PROGRAM).

I came up with a simple way for the selector switch to control the 7-segment LED so it shows 1-4 based on the switch position - using a network of diodes. The diodes prevent current from flowing in the opposite direction and turning on all the connected segments. However, since current flows from negative to positive the 7-segment LED needs to be of the Common Anode (anode=positive) variety.

The RemoteLinc2 requires a regulated 3.9VDC power supply to operate correctly. I wanted to be able to run the remote off of either 9-volt (used on my UV LEDs or blinking eyes) or AA (five times the life) batteries and the voltage regulator actually made this possible. I can connect a 4xAA pack or a single 9V battery to the battery snap connector that goes to the voltage regulator and I will always get 3.9VDC. The voltage regulator circuit and the diode network went on a couple of round PCBs purchased from the neighborhood Radio Shack.

PVC Remote Diode Array PVC Remote Diode Network section PVC Remote Voltage Regulator section

The round PCBs are glued to three nylon rods spaced equidistant from eachother and the whole assembly slides into the PVC housing.

It's fairly easy to hold while wearing a costume, and one hand can slip to either the selector knob or the activation button while the other hand holds onto the body.

PVC Remote Fits

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