Controlling Your Robot: IR Remote Control Kit
I wanted to add a simple remote control to Maxwell. Nothing fancy – just an IR link to control him forward, backward, right, left, and stop. While I was visiting the Hobby Engineering store in California I happened across the “Kit 92 IR Remote Control & Decoder IC” by Kitsrus.com (as in “Kits are us”, not “Kits Russia”), and since it was only $12.95 I picked one up.
The kit comes in a thin walled plastic box that houses the remote control, components, and an instruction sheet. Their site includes a pdf copy of the instruction sheet.
Here’s the label on the box. Note the “sample circuit supplied” comment.
The components include the decoder chip, a 12 Mhz resonator, three capacitors, an LED, four resistors, a diode, and the IR receiver module. There is no circuit board. The expectation is that you will breadboard the circuit using the components supplied, and then incorporate your proven circuit into a larger circuit design.
The decoder chip is a preprogrammed Atmel controller.
The 3 pin IR module is a Waitrony PIC1018SCL. They provide a link to the Waitrony datasheet (pdf.)
There is also a nice resistor color code chart included in the kit. This was quite handy since I always have trouble remembering the “Bad Boys R… Our Young Girls, But Violet . . .” rhyme.
The remote control unit is pretty cheap, and the buttons feel it. Still, what do you expect for $12.95?
The emitter end of the remote control. I definitely plan on testing the range and pattern before I let Maxwell run around free on the floor.
The remote control takes two AAA batteries (batteries not included.)
The pins on the decoder chip were pushed through foil and then into plastic. That’s okay, I guess, but I always worry about static electricity zapping my electronics.
The circuit was very simple and straight forward to breadboard. The IR detector is in the upper right, the decoder chip in the middle, and a LED to give a visual indication is at the bottom. For the initial testing I only hooked up one output of the decoder. The kit only provides you with the components for one output, assuming that you will be linking the outputs directly into your robot’s controller inputs.
The instructions show a pinout table for the decoder chip that’s easy to follow since it’s laid out in the same order as the chip pins.
I only found one significant error – a typo that mislabels pin 9 as pin 8.
URLs are listed for their website, the IR receiver module datasheet, and to contact them via email. They offer to sell you any extra components, but only sell the complete kits via their dealers and distributors, like Hobby Engineering. One concern I have is the statement that “The code inside the decoder IC is locked and is not available.” I can totally understand and appreciate their position. I would probably do the same thing. Still, as a hobbyist, I want to take things apart and modify them. For example, their decoder’s outputs are individual lines. That requires me to either use a lot of input pins on my robot’s controller, or add some additional circuitry to compress/encode the signals. I would rather just modify the code inside the decoder so that it outputs the codes I want directly. I have to give it more thought, but I suspect I may end up doing a version of the code using a PIC chip.
The instructions are a single sheet, printed on both sides. The front side includes the component list, pinouts, circuit description, and supporting background information.
The back side of the instruction sheet includes a sample test circuit. Note all the LED’s and current limiting resistors tied to the outputs. This is purely for demonstration and test purposes – not something you would actually use verbatim in your robot design.
Conclusion: The K92 IR Remote Control & Decoder IC kit is well thought out, and does everything as advertised. It was good for testing and prototyping. If your needs aren’t very complex or demanding, it may work well as a part of your design.