RRW1B | Ramsey Electronics rrw1b instruction

When the IR detector on the RRW1A (transmitter board) “sees” a 38 kHz IR signal, the output of the detector goes low (it is inverted). When there is no 38 kHz signal present the output idles high. On the output of the IR detector you won’t see the 38 kHz, just the data that the 38 kHz represents from your IR remote control. This data from the IR detector is then used to switch on and off a 433.42 MHz oscillator. Instead of switching an LED on and off at 38 kHz, we are now switching an electrical field on and off at a rate of 433.42 MHz. This acts as our new carrier frequency for the wireless part of the kit.

The oscillator section is a Colpitts style oscillator formed by Q2, C7, C8, R6, and X1. The oscillator is turned on and off by Q3 through resistor R4 in accor- dance with the received IR data. When a data pulse is detected by U1, its out- put goes low pulling the base of Q3 low to turn it off. When Q3 turns off, the collector (R3, R4, and Q3 junction) is pulled high so the needed bias voltage is applied to R4 causing Q2 to turned on and begin oscillating with the surround- ing parts. Turning Q2 on and off performs the on-off data keying (OOK modu- lation) that we require to re-broadcast the IR signal.

The RRW1B (receiver board) has a specialized receiver chip which is also set at 433.42 MHz. The receiver detects whether or not a 433.42 MHz field is being broadcast and only sets its data output high if a signal is present. The RRW1B will replicate the transmitted data by turning its data out pin on and off at the received data rate. To re-send this data, we have to modulate a 38 kHz carrier again in accordance with the data the IR detector puts out. By using a micro-controller the data output from the IR detector can be sampled and a Pulse Width Modulated (PWM) signal at 38 kHz can be generated in accor- dance with the detected data.

By using this method with a micro-controller, we can add some intelligence to the regenerated signal as well. The sample IR remotes we have looked at send their data at a rate of around 2400 bits per second. This means that our minimum pulse length for a zero should be 1/2400 x 0.30 seconds long (125 uS). Consider this example, let’s say that the signal from the IR remote is weak and it fades out due to interference from some other IR source before the data pulse is finished (i.e. 80 uS instead of 125 uS). The micro-controller will continue to send the 38 kHz until 125 uS is up, not allowing the re- transmitted signal to drop out the way the original source did. This error cor- rection feature can be disabled in case you have a strange remote that is not compatible (to this point we have yet to run across one that doesn’t work). Re- move the jumper from J21 to disable this feature and have U21 blindly re- create the data it sees.

Once the micro-controller on the receiver board has re-generated the 38 kHz carrier (modulated by the data), its output is buffered by a transistor stage that drives the high power IR LED used to control your equipment.

Wow! There’s a lot going on here!

RRW1B • 6

rrw1b specifications

The Ramsey Electronics RRW1B is a versatile and compact wireless transmitter and receiver system designed for various applications, including remote control and communications. This innovative device operates on the 27 MHz band, offering a robust solution for users seeking reliable wireless connectivity. One of the standout features of the RRW1B is its impressive transmission range, allowing for operation up to 1000 feet under optimal conditions. This makes it suitable for both hobbyist projects and professional applications where distance and reliability are critical.

The RRW1B utilizes frequency modulation (FM) technology, which ensures clear signal transmission and minimal interference from other devices operating on similar frequencies. Its design incorporates advanced circuitry that enhances its performance, contributing to a stable link between the transmitter and receiver while effectively reducing noise. This technology is particularly beneficial for applications in remote sensing, data logging, and control systems where accuracy is paramount.

Another notable characteristic of the RRW1B is its user-friendly interface, which allows for easy setup and configuration. The system is designed with the end-user in mind, featuring color-coded terminals and intuitive controls that facilitate straightforward installation. This aspect makes it accessible to both beginners and experienced technicians, reducing the learning curve typically associated with wireless systems.

The RRW1B is also characterized by its low power consumption, making it an energy-efficient choice for long-term use. This is particularly advantageous for battery-operated devices, extending their operational lifespan and reducing the frequency of battery replacements. Moreover, the RF (radio frequency) modules used in the RRW1B are known for their durability and resilience, ensuring that users can rely on the system in various environments, including those with challenging electromagnetic conditions.

In summary, the Ramsey Electronics RRW1B stands out due to its excellent range, FM technology, ease of use, and energy efficiency. These features make it a popular choice among hobbyists and professionals alike, providing a seamless wireless solution for a myriad of applications. Whether users are looking to enhance their home automation systems, develop remote-control gadgets, or implement wireless data communication, the RRW1B proves to be a capable and dependable option. Its combination of performance, simplicity, and versatility makes it a valuable addition to the toolkit of anyone interested in electronics and wireless technology.