This is a DIY video tutorial on how to build a pneumatic automated halloween prop. This prop is a dresser with two drawers that open and close after a human triggers a sensor.
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Are you like me and love to decorate for Halloween or just about ANY festivity? I love using automation for props. Many years ago we built a multi themed haunted house right here at Automationdirect. A couple years ago we created a series of how-to videos for one of the Halloween props we used in our haunted house and that series was a hit with our viewers. If you didnt see it, go back and watch how I automated this alien head. Another one of my favorite props in our haunted house was a dresser that had automated drawers. In this video, I am going to re-build this favorite prop and show you how to impress your visitors and trick or treaters. In this video, I will explain how to build a completely programmable automated system that you can build on a budget and can tailor to your needs or application. Now.. these don't HAVE to be used for Halloween props, but I thought that since a lot of people we have talked to enjoy creating projects like this then why not? Besides, some of our customers are professional prop companies and while an example like this may seem unconventional to you, it is every day business for others. What we want to accomplish with this prop is: A human walks by and trips a sensor telling the PLC to control pneumatic valves and in turn opening and closing the dresser drawers automatically by extending and retracting two air cylinders. After a set amount of time, the system shuts down, both drawers will close and the system will be ready for the next victim. I mean human. In this system I use two pneumatic cylinders to move these two drawers in and out sporadically and I use two electrically operated pneumatic solenoid valves to control the cylinders, a photo sensor to detect human presence and a CLICK PLC to control the whole system. All of these products can be purchased here at AutomationDirect. Lets start with the air cylinders. On the original system we built years ago, we mounted the air cylinders to the back of the dresser and attached the air cylinder rod to the dresser drawer at the back like this. This worked fine, but wouldn't allow for the dresser to be moved flush or near a wall. We needed around 16 inches or more of clearance for the air cylinders. It also made storing and moving the prop difficult because we had to be careful not to damage the air cylinders. In this new example, I mounted the air cylinders to each drawer bottom and then drilled a hole through the back of each drawer for the rod to extend through and then connected the rods to the back of the dresser. This was just a simple flat pack style night stand or office drawer. As you can see, I beefed up our dresser in several ways: I disassembled the dresser and glued every joint, and then used counter sink screws to make sure it was solid. This prop will be bouncing back and forth and we don't want it falling apart during operation. I also removed the back of the dresser and cut a sheet of aluminum for the backing. This gave us a robust back to connect our air cylinders to as well as gave us somewhere to mount all of our controls. If I were to use this in a facility where the public would be involved, I would have used an enclosure to mount everything out of the way and secure all of the wiring so there would be no potential electrical hazards. In this example I mounted everything to the back so I can explain better and show you how it all comes together. Also, someone asked how could the air noise be eliminated? Well, again, if I moved the controls to a remote location, then you wouldnt hear the air releasing from the solenoid valves. This system has standard 2 port air cylinders. I selected three quarter inch bore since we dont need much force to open and close the drawers. I measured my drawer size and then measured how far the drawer opens. I then selected an air cylinder length based on these measurements. In this case, since my drawer is fourteen inches deep, I chose a twelve inch long cylinder. We could have used several other options like spring return or larger bore cylinders but this one worked fine for our application and is cost effective for the average DIY-er. The brackets I used to mount the cylinders are all accessories sold by AutomationDirect. Next, we chose to use 2 solenoids to control the cylinders. We selected 4 way, 2 position valves, so we can extend or retract each air cylinder with their own valve. The part numbers we used were: AVS-5312-24D these are 24Volt DC valves. These valves normally stay shut (drawer closed) and when electrically actuated, they open (drawer opens). So we simply turn on and off the one solenoid with one PLC output in order to move the dresser drawer in and out. We could have also chosen 4 separate 3 way 2 position valves or we could have put these two valves on a manifold together to clean up the pneumatic fittings. Had I chosen to use larger air cylinders, I would need to account for the large air volume needed in order to move the cylinder rapidly. This means that I would have had to use larger fittings, larger air tubing, larger hose and larger capacity air valves. So keep all of these factors in mind when selecting your parts. I selected our CLICK PLC to be the brains of this project. I did this for 3 reasons A, it is self-contained, so no additional parts or IO cards are needed, B: it is very inexpensive and C: the software is FREE! No need to overcomplicate a project or spend un-necessary money. We could have used a number of Automationdirect PLCs, but the CLICK is inexpensive, the software is easy to use, and it leaves us with tons of capabilities to expand if we need to. In other words, if we ended up wanting to use 10 or 20 of these automated systems in a haunted house, we could control each one of them in the same or different ways or pretty much control the WHOLE haunted house with one PLC. Next, lets discuss the plumbing. We plumb our main air source into the solenoid valves. I am using 4 way valves so, we have a supply in, 2 ports offer air out and then we have our exhaust ports. These valves allows us to trigger air to one side to make the cylinder extend out, trigger the air to the opposite side to make the cylinder retract in. Next, we plumb the 2 ports that will supply the air to the pneumatic cylinders. I chose to use these adjustable flow control fittings here they allow us to adjust the air pressure at the cylinder in order to speed up or slow down the flow. This makes the action smoother and prevents damage to our cylinders. Now that the system is plumbed, lets wire it up. This may get a little complicated for some and if it does, or if you dont have the skills or knowledge to work with electricity, we suggest hiring or finding someone that does so you and your system remain safe! First, we need to wire up the DC photo sensor we have. I chose an 18mm plastic housing photo sensor part number: FA18-BN-0A. The DC sensor as well as the solenoid valves are powered by this Rhino DC power supply. I wire the sensor to the input X1 of the PLC. Next, we wire up the outputs Y1, and Y2 on the PLC to the solenoids. An extra step I made is to use a suppression diode on each output. The reason why is solenoids can generate a spike in voltage and will send an over voltage to the PLC and potentially damage the IO cards or anything else in the circuit. To avoid damage, we use diodes to suppress or capture the spike. I am using a pre wired solenoid cable that we sell here at AutomationDirect, it is part number: SC11-LS24-3R. This cable has built in suppression, so no need for external diodes, PLUS it saves us wiring time which time is money. These are inexpensive, easy to use and will save you money and headaches in the long run. Now, the last step is to wire up the power to the PLC itself. Since we have a 120vac supply voltage, we need to use this CLICK power supply, because the CLICK PLC requires 24vdc to operate. You may be thinking: Why didnt we omit this part and just power our CLICK PLC from the main 24vdc Rhino power supply? Well, we could have but its not good practice to have your control power and IO power on the same source. It is recommended to separate the two so you are less likely to have voltage noise and spikes on your PLC power. This keeps the PLC happy and operating well. I also installed 4 air cylinder sensors so we can tell the position of the air cylinders. This will allow us to detect cylinder position and stop air flow and allow us to adjust our air cylinder travel if needed. These were not a necessity but a bonus once added to the system. After programming, I decided to keep it simple and not incorporate these into the program even though they are wired up and installed. Last is programming the PLC. There are many ways of programming what our end goal or result is, and I wont go into great detail on programming, but simply show you how I programmed this system with a few lines of code. We offer detailed programming videos and training videos here at AutomationDirect and if you need further instruction, we have the resources for that. The code I used says that if the sensor is triggered, it turns on input X1. This will in turn set an internal bit which we assign to C1. When C 1 is on and set, we start a timer T1 timing. This timer times in seconds up to 15 seconds. As you can see, I have several compare statements using time values from the timer T1. For example, rung 3 says if the timer value of T1 is greater than 1 second and less than 1.5 seconds, then turn on internal bit C10. I do this with several rungs using several time compare statements that way I can turn on the output at different times. On rung 7, I program: if Internal C10 or C11 or C12 or C13 is on, then turn on our first output Y1 which is controlling the solenoid valve that controls the air cylinder attached to our bottom drawer. So every time the timer value compare statement is true, an internal C bit is turned on and that C bit turns on the output. This code gives us 4 open and close actions for each drawer. The code I used for the top drawer is basically the same but I staggered the open and close timer values so the drawers act at opposite times. If I wanted to program the drawers opening and closing more than 4 cycles, I could have easily extended the timer T1 up to 20 or 30 seconds and added more rungs or lines of code with compare statements and internal C bits. At the end of the code I used, Rung 13 says that when the timer value is equal to or greater than 10 seconds, it resets our first internal bit C1. This resets the system where the sensor is now ready to be triggered again. I could have used several different styles of code to achieve this same result, this is just one of them. Now, I put the PLC in run mode and trigger the sensor, you can see what happens. OK, Im happy that we were able to show you one of the ways to build a prop and obviously there were many ways of achieving this same goal. I hope you are able to stop by AutomationDirects website and pick up a few parts, and be on your way to creating your own automated Halloween prop or just something fun. Please, if you create something cool, drop us a line or a link to your system in the comment fields below. We would love to see what you have. Keep in mind All of the products we have used in this system are products that AutomationDirect sells with the exception of the air compressor and the dresser. The tubing, fittings, wires, terminals even the Teflon tape are all sold here at Automationdirect! So keep us in mind for all of your automation needs. Now that this prop is completed, I will start working on an addition to this one for our next Halloween prop DIY video, so keep checking back for new videos to come. Thanks for watching and we hope to see you again soon.