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ARTICLE FROM JANUARY 1997 CALLING ALL COUCH POTATOESControl Almost Anything via Infra-Red Remote by Randy Nelson, WB0VHB Have you ever bought a kit and been disappointed when it didn't work like represented? I have and usually regretted the purchase. Some of my disappointments still gather dust on the shelf in my shack. There is one such kit that I would like to recommend. It is from Weeder Technologies, Box 421, Batavia, Ohio 45103 and it does work as advertised. The story begins when I recently built a motorized camera. The camera is mounted on a motorized pan/tilt mount. This motorized camera will be located either on my tower or roof. The video will then be modulated on an unused cable channel and distributed to my TV sets. I wanted to be able to control where the camera was pointing from any room in the house. Initially, using DTMF was considered. The biggest disadvantage was the encoder would have to be based around an existing walkie-talkie which was big, heavy and hard to operate with one hand. I also looked into a few remote controls used in the burglar alarm industry. These controls were used for remotely turning on and off alarm controls. Five functions were the most I could find from any manufacture. This was two less than I needed. They were small but didn't have enough control functions. The cost was also over $100.00 for both receiver and transmitter. After considering several methods, I found a way to control the camera with my existing TV remote control. This was great. Now I could control the camera and the TV with only one control. Also more than one control would be available for much less than an additional WT. While reading an issue of Electronics Now, I found a kit that can learn the commands from an infrared remote control. It has a low parts count and the price was only $ 35.00 including shipping. Seven output lines are available. Each line can be programmed to be a latched output or active as long as the remote button is pressed. This worked perfectly for my requirements. I used up, down, left, right, zoom in and zoom out as momentary and camera power on/off as a latched output. A silk screened printed circuit board is included in the kit as are all on board components. Assembly took less than 30 minutes. There is also vacant space on one end of the PC board. I used this area to install a 2N2222 switching transistor for each output. An LED on each output shows it's activity. The transistors and LEDs were not in the kit. Programming the controller is very easy too. Any infrared remote can be used since the controller will learn the remote's commands. The controller uses a PIC chip and can be reprogrammed. Memory is not lost if power is removed. The process begins by applying power to the controller. The programming pin is grounded and the status LED lights. The remote control is then placed about 12 inches away from the controller pointing at it's IR detector module. The seven output lines are then programmed by pressing the button on the remote you want to control that output. Each line is programmed in sequence starting with one. As each button is pressed, the status LED blinks off then on. If you want the control to be a latched output, then press and hold the remote button down until the LED flashes a second time. When all seven outputs have been programmed the status LED will turn off. The remote control I used is made by RCA. It is a programmable remote and will control a TV, VCR, satellite receiver and an alternate device. The remote comes with a sheet which includes three digit codes for most of the popular TV's and VCR's. I programmed the remote's Alternate button with a code that no other company uses. Multiple controllers could be used. RCA had already solved the next problem I was to encounter with a remote control extender. Since the camera, it's motor and the controller would be located either on the roof or tower, I wasn't going to have the line of sight IR remotes need. The extender consists of two small black plastic cones about 5 inches tall. One serves as a receiver and the other the transmitter. The transmitter or transmitters are located in the rooms where you are going to use the remote control. The transmitter picks up the infrared signal and converts it to RF. A receiver then converts the RF back to an infrared light signal which is beamed to the controller or other device you wish to control. This was a fun project that didn't require me to reinvent anything. And best of all, it works! Randy Nelson, WB0VHB Comments to rnelson@se-iowa.net Comments
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