Engineering Solutions Inc

In addition to the standard products listed in our web store, we do quite a bit of custom / one-off work.  Here’s a collection of recent quick-turn projects we’ve recently shipped.  All images here can be enlarged with a click.

The DMX Triggered DMX Selector Switch

A theatre up north had several lighting control sources (a large lighting console, several wall panels, etc) plus safety rules which require certain channels be kept at a specific intensities 24/7.  Based on their sketch and pseudocode, we designed a five input DMX router.

For any input, setting a specific channel to a specific value lets that DMX source take control, and its full universe of data is passed to the ‘DMX Out’ jack.  In addition to switching between the five inputs, the system forces the safety channels to their proper values and sends the final signal downstream.

If you think about it, in this situation, a standard DMX merger running either ‘highest takes precedence’ or ‘most recent takes precedence’ wouldn’t work properly.  The system contains a USB interface for painless field firmware updates if they’re required.  Each DMX input is optically and galvanically isolated from its neighbor, which should keep lightning propagation to a minimum.

Side note #1: Our stock DMX receive circuitry has been installed in thousands of locations worldwide.  And in over a decade, we’ve never, ever received a report of it being damaged in any way.

A Countdown Timer / High Power UV Trigger System

Though not one of our usual DMX / MIDI / serial projects, we’d worked with staff at this childrens’ museum several times in the past.  It’s rewarding to deliver something which didn’t exist, anywhere in the world, until we made it so.

In a dark corner of the museum’s ‘color and light’ lab, an entire wall was painted with photoluminescent paint.  When excited by a xenon strobe light, flashlight or blacklight, the paint activates and glows green for several seconds, slowly fading away as the energy dissipates.

The designers envisioned a ‘photo booth’ where patrons could press a trigger button and then pose against the wall.  The paint is then activated by the light source, leaving a glowing silhouette.

We sourced a pair of 10W UV lights (395 nm and super intense, causing mild eyeball sunburns after twenty seconds of near-field exposure) and a 4″ illuminated pushbutton.

I felt that standard 7-segment displays looked mechanical and dated, but a quick search online returned a slightly stylized 7 segment font – ‘Modern Mini’ in bold italic.  The ~5 degree slant looked fun, and I liked how the segments jauntily meshed together.

It took a few steps in the CAD program, but the digits were converted to vector data.  On the shop’s laser cutter, we created a 7-segment display measuring 300 x 200 mm.   The display was loaded with LEDs whose brightness and color can be arbitrary controlled, segment by segment.   The finished assembly is a sandwich of several acrylic layers, using black, clear and white stock.  The segments are inlaid in the black layer, then covered with a clear protective layer.  The layers allow the light for each segment to be channeled, diffused and displayed in a pleasing way.

Also, the giant pushbutton contains a white LED which can be set to any intensity.

Our custom circuit board include a small display for changing and storing settings (UV / flash exposure time, countdown time and ‘timeout’ time).  It was somewhat overbuilt, supporting 4 contact closure inputs, 4 buffered logic level outputs, a pair of high power output stages and 4 SSR (solid state relay) outputs, in addition to connections for the countdown display and a smattering of indicator lights.

During normal operation, the display reads ‘5’ in green, and the pushbutton pulses slowly, à la sleeping iMac, drawing attention to itself in a tasteful way.  When the button is pressed, the white LED turns off and the countdown begins.  At time zero, the UV sources pulse for their specified time, the display switches to blue and begins begins counting down from the ‘lockout’ value, giving patrons a chance to enjoy their artwork as the phosphorescence slowly fades away.

Once the lockout time has passed, the pushbutton resumes its quiet pulsing, the display switches back to green and waits patiently for input.

Side note #2: The blue / green color scheme was chosen in a nod to the industrial designers at Disney. Green means go, blue means wait.  Red signifies danger and problems, so don’t bother the public unnecessarily.