Design Con 2015

Bulldog Security RS82B remote-vehicle-starter system

-June 23, 2011

Bulldog Security RS82B remote-vehicle-starter system top imageA diligent press-relations person offered me a remote-starter system to evaluate. I explained that, because EDN is a highly technical magazine, my evaluation would require that I take the starter apart. The company was OK with that. I was able to pry into the guts of the microprocessor-controlled unit as well as the RF key fob you use to operate it. I was astonished to see that the remote operated from 12V. The main unit provides an excitation coil for your car’s spare smart key so that the unit can disable the car’s security system when you start it remotely. The 400-foot range sounds nice, but this unit works only on automatic-transmission cars built after 1982, so my ’92 Honda can’t use it.

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Prying Eyes write-ups

Bulldog Security RS82B remote-vehicle-starter system image 1
Bulldog Security RS82B remote-vehicle-starter system image 21. This large copper winding excites a spare car key that you clamp in the foam holder. It allows the system to excite the key and turn off your car alarm.

2. Two large and five small relays interface with the car’s starting circuits. You can’t beat a relay for isolation or low on-resistance, as well as low cost. The relay manufacturer is a Chinese company, Sanyou, not Sanyo of Japan.

3. An 8-bit 46R0662 Holtek microprocessor with ADCs, in a 44-pin QFP, controls the system.

Bulldog Security RS82B remote-vehicle-starter system image 34. Parts reside on both sides of the PCB (printed-circuit board). They include a Texas Instruments relay driver and National Semiconductor op amps.

5. A double-sided PCB has parts on one side only. A 20-bit Zhengxin Microelectronics LX- 2240B remote-controlencoder IC holds 1 million codes. You apply the 12V battery to the chip when you press either button. The RF amplifier is an NPN transistor with a crystal tank circuit.


Editor's note: The original version of this article contained an error, which has been corrected in the text above and in the associated PDF file. "1996" was changed to "1982" on June 24, 2011.

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