Popsicle Kitteh Pandemic Entertainment System - City Tech Show Control Class Project
One of my favorite classes I teach at City Tech’s Entertainment Technology department is Show Control. Show Control, as I define in my book, Show Networks and Control Systems, is connecting two or more entertainment control systems (lighting, sound, video, machinery, etc) together. I’ve worked with this integration technology since the 80’s and have taught this class for many years at City Tech almost entirely hands on. Students start out with QLab, and then move onto programming our Gravesend Inn™ animatronic character via its control system based in Weigl/Conductor. The second half of the semester is based in network-centric Medialon Manager. Fortunately, when the pandemic hit, we had completed the first two hands on subjects, and since Medialon has a free demo mode, students are able to work at home on a PC. However, a big part of the class is controlling real systems such as lighting consoles, video servers and other similar devices, and this wasn’t possible while the school was closed down for COVID-19. But I figured out that with some gear I had, and grabbing a couple small items from school on my way out, I could set up a system in my tiny Brooklyn spare room and let the students remote access it via Team Viewer. Medialon generously sent me a software license key and as I had an hour here or there over the last few weeks I built up the system around an extra Lenovo laptop and a PetSafe Train ‘n Praise Dog Treat Dispenser.
Let’s go through the technical detail starting with a system block diagram.
Medialon Manager is the show control software development environment that ties everything together (center laptop picture); it connects to an Automation Direct DL05 Programmable Logic Controller (generally used for machinery and industrial control, left in the diagram) via an ethernet switch (center). The retroreflective photo-electric sensors (top left) are wired to the PLC, which is polled by Manager using MODBUS TCP over the network; my code can then react to the sensors. I put one sensor at the entry door to the room and another on the table. Luckily, the sensors fit into a mic clip and stand that I had (as you can see at the beginning of the video) and the other I clamped to the table (the extra clamp to keep the main one from moving).
These sensors need a retro-reflector. After some experimentation I double-sticked one to a door and cable tied another to a book end and clamped it to the folding table.
Manager also sends commands to the PLC to close a relay to activate the treat dispenser, which took a bit of time to work out. I opened up the unit as soon as I got it from Chewy (who apparently no longer sells it, it looks like I got some kind of close out deal) hoping there would be something I could hack inside for simple on/off contact closure control from a relay in the PLC. Unfortunately the control circuit board is all surface mount with a chip and the only thing there was some test points. Emails about the test points to PetSafe went unanswered, so after a bunch of testing I went old school and just soldered wires across the remote control button. So effectively, the PLC, when instructed by my code, pushes the button on the wireless remote, which then activates the feeder.
I stuck the PLC and sensor power supply in a plastic box for safety reasons because there is some exposed line voltage there.
Popsicle kitteh seemed to appreciate this safety feature:
The brightsign player (blue device in the center) is a powerful and affordable media player (I own this one for teaching networking workshops), and I’ve written about them before. The are programmed using BrightAuthor software (see below), and can be programmed to respond to simple UDP commands, in this case to play back still photos and a couple videos via HDMI out to my little monitor.
The final controlled device in the system is an old LightMaster MIDI-controlled dimmer. There are far more powerful, network based solutions for control these days, but these are great for class projects. Each outlet on the dimmer is addressed via a MIDI note, with velocity mapping to brightness. I’m controlling a little dimmable LED light and also the fan (which I don’t dim since it’s a motor).
I got one of the last cheap webcams from Amazon before they sold out, and fortuitously it fits into the clamp of a camera monopod I have. Manager can display this right on a user screen.
I made a basic test program in Manager to work out the I/O and give a starting point to the students (they are assigned to write their own code). I also included two automatic time based sequences for demonstration, triggered by the sensors and enabled/disabled using buttons on the screen. (Click to enlarge.)
Of course there were many things to figure out on this project, but I’ve never had a kitteh involved before. She knocked the treat dispenser onto the floor, breaking the lid hinge, and so now the lid is taped down and the whole unit is wire-tied to a metal book end, which is clamped down to the little monitor platform. I try to be consistent and only run the dispenser when there are treats inside (which she can smell), but even when I have the dispenser disabled, she has learned the sound of the control relay. So she will often sit back there if she can smell treats.
Popsicle is on Instagram.