How- to: USB remote control receiver. Now that we listen to MP3s, and watch XVIDs or x. Unless you have a special HTPC, though, you’re probably stuck using the keyboard to pause, change the volume, and fast- forward through annoying Mythbusters recaps. PC remote control receivers range from ancient serial port designs (who has one?) to USB devices not supported by popular software. In this how- to we design a USB infrared receiver that imitates a common protocol supported by software for Windows, Linux, and Mac. Media Receiver 300 Usb HacksawWe’ve got a full guide to the protocol plus schematics and a parts list. Design overview. Remote controls transmit data on an modulated infrared beam. An infrared receiver IC separates the modulated beam into a clean stream of 0s and 1s. The data stream is decoded by a microcontroller and sent to a computer over a USB connection. Software processes the codes and triggers actions on the computer. Background. Computer infrared receivers. The oldest PC infrared receiver design uses a receiver IC to toggle a serial port pin, usually DCD. Media Receiver 300 Usb Hack KaliAudyssey Bronze is our entry level of support for Audyssey technologies and includes Audyssey MultEQ, Audyssey Dynamic Volume, and Audyssey Dynamic EQ. How I did it with the instructions below. http:// http:// 38kHz Infrared (IR) Receiver Module. This design probably originated on Usenet, and it’s still the most popular on the web: Engadget, Instructables, etc. These aren’t true serial devices because they don’t send data to the PC. Instead, a computer program times pulses on the serial port and demodulates the signal. This is a super simple design, but it depends on direct interrupt access and timing precision that’s no longer available in Windows. Linux or Mac users can try this receiver, if you still have a serial port. We couldn’t get this type of receiver to work with the serial port on a modern Windows XP PC, and don’t expect the precise timing to transfer through a USB- > serial converter. Some more advanced infrared receivers are true serial port devices that measure or decoding infrared signals before sending data to the computer. The UIR/IRMan and UIR2 incorporate a classic PIC 1. F8. 4, but don’t provide firmware and/or source code. These devices should work on a modern computer, through a USB- > serial converter if necessary. The USBTINY and USBIRBOY are native USB devices, but lack wide support. Receiver software. Regardless of receiver type, the computer needs a program to listen for incoming remote commands and convert them to actions on the computer. Linux and Mac users have LIRC, which supports a bunch of different receiver types. Windows users are a bit less fortunate. Win. LIRC is an abandoned Windows port of LIRC for simple interrupt- based serial port receivers; Win. Sony DSX-S310BTX Single DIN Bluetooth In-Dash Digital Media Receiver with Integrated Tune Tray, Dual USB 1-Wire Inputs and Detachable Faceplate. Bolt Sidekick Receiver. Bolt Sidekick is a lightweight universal companion receiver for Teradek Bolt Pro 300, 6 systems. At only 9oz, Bolt Sidekick is the. The AVH-X7500BT 1-DIN multimedia DVD receiver features a beautiful motorized 7' WVGA touchscreen display, Pioneer's own MIXTRAX™ technology, built-in Bluetooth. ATSC Digital TV USB Tuner Ready. The Jynxbox Android HD is ready to support ATSC USB tuners that will get you over the air content from all over North America in. Optical Drives. Pioneer provides high quality computer accessories. Products from SATA and USB Blu-ray and DVD burners, to on-ear or earbud headphones and USB powered. Insert batteries in the remote control. Plug in the receiver. The device will enter its initial setup procedure. The first prompts will ask you to choose a language. LIRC was last developed in 2. Girder was originally a freeware PC automation utility, but has become expensive bloatware with a 3. Fortunately, the last freeware version of Girder (3. Working with IR remote protocols. Decoding IR signals. Remote controls encode commands in the spacing or timing of a 3. KHz carrier pulse, [San Bergmans] has an explanation of the principals involved. An infrared receiver IC separates the data stream from the carrier. Our job is to decode the data stream with a microcontroller. There are dozens of remote control protocols, but Phillips’ RC5 is widespread and commonly used by hobbyists. RC5 is stream of 1. A pulse during the first half of the bit time represents 0, a pulse in the second half represents 1. This scheme is called Manchester coding. We used a logic analyzer to examine the output of a Happauge Win. TV remote control, a known RC5 remote. The diagram shows two presses of the 1 button, and two presses of the 2 button; note that the output is inversed and the Manchester coding is backwards from the above description. The first two bit times are start bits, followed by a toggle bit. The toggle bit inverses each time a button is pressed so the receiver can tell the difference between a hold and a repeated press. The next 5 bits are the address (0b. E), followed by the command (0b. A backwards compatible extension to RC5 uses the second start bit as command bit 7. Representing remote codes to the computer. Looking at previous designs, we saw three general methods of communicating remote commands to a computer: Protocol specific receivers decode one protocol, and send actual decoded commands to the PCA more general type of receiver measures the timing and spacing of each pulse and sends the full waveform to the PC for analysis. Some receivers create a unique hash for a signal, but don’t actually include enough data to fully recreate the waveform. While our preference is towards the general hash method, our only remote uses RC5 and it was more interesting to build an RC5 specific decoder. We describe modifications for a more general version in the firmware section. Computer interface protocol. We didn’t want to write our own receiver software or driver, so we looked for an existing, well established communication protocol to imitate. The UIR/IRMAN/IRA/CTInfra/Hollywood+ type receiver is supported by Girder and LIRC, and uses a simple serial protocol with handshake: The device is initialized by the DTS and DTR pins of the serial port. We don’t have these and don’t care. The computer sends “IR”, with an optional delay. The device replies “OK”. We’ll just send “OK” on every “R”Remote control codes are sent as a unique six byte hash. We’ll decode an RC5 signal and send the actual values, but a generic hash could be used instead. This protocol is for a serial port device, but our USB receiver will appear as a virtual serial port and the program won’t know the difference. Hardware. Click here for a full size schematic (png). Our receiver is based on a USB enabled PIC 1. F2. 45. 5 microcontroller, the smaller, cheaper version of the 1. F2. 55. 0. The 1. F family is programmable with the hobbyist favorite JDM- style programmers if a diode is used to drop VPP to a safe level. The PIC gets one decoupling capacitor (C1), and a diode (D1) and resistor(R1) on the ICSP programming header. We exposed the serial port on a pin header for debugging or a mixed USB/serial port version using a MAX RS2. IC. The USB peripheral requires a 2. MHz external clock (Q1, C5,6), and a . F capacitor. We faked the capacitor using 2 x . F decoupling capacitors (C2,3). A 3mm LED (LED1) and a 3. R2) show USB connection status. We used a TSOP- 1. IC which calls for a 4. F decoupling capacitor (C4). If you can’t find this particular IC, any receiver listed here should work. The TSOP- 1. 73. 8 output is the inverse of the received signal, it pulls to ground when a pulse is detected, so a pull- up resistor (R3) holds the pin high when no signal is present. Check if you use a different receiver, you may need to use a pull- down resistor and reverse the Manchester decoding routine in the firmware. The circuit draws power from the USB bus, so we don’t need an additional power supply. Parts list. Click here for a full size placement diagram (png). The PCB design is 1. The schematic and PCB were made with Cadsoft Eagle, freeware versions are available for most platforms. All the files are included in the project archive (zip). Firmware. The firmware is written in C using Microchip’s free demonstration C1. Firmware and source are included in the project archive (zip). We used version 2. Microchip’s USB stack to create a USB serial port using the default drivers already available on most systems. The USB stack has simple functions to enumerate the USB device and transfer data between device and host. It only took a few pin changes to get the CDC demonstration working on our custom hardware. Our implementation of the UIR/IRMAN/IRA/CTInfra/Hollywood+ protocol simply responds to the letter ‘R’ with ‘OK’. This should satisfy the handshake requirements of any implementation of this protocol. We chose to specifically decode RC5 (and RC5x) because it’s a widely used protocol, and the only type of remote we have to work with. Most of the decoding is done in the interrupt handler: The first signal change triggers an interrupt that starts a 8. On each timer interrupt, one- half of a Manchester coded bit is sampled. Every other interrupt the measurements are compared, and the bit value is calculated to be 0, 1, or an error. Errors reset the decoding routing. At the end of each transmission the address and command bytes are decoded, and sent to the host with 4 buffer bytes(0). We discard the toggle bit because it would confuse the PC software into thinking every other press was a unique code. We append the second start bit to the command bit for RC5x compliance; this just adds 0x. RC5x remote codes. A more general version can be made by removing the Manchester coding step (3), and sending 4. Installing the USB infrared receiver. Most operating systems already have drivers that support a virtual serial port device like the receiver. Windows XP has the required drivers, but needs help from an . Windows will show the new hardware dialog the first time you plug in the receiver. Choose to use a custom driver and point it to the . This links the device to a driver already included in Windows, and adds the receiver as a COM port. You can check the COM port number in the control panel. Mac and Linux users can use the receiver with LIRC, but Windows users will be faced with the choice of the old, freeware Girder, or the new, 3. We used the freeware version of Girder, but hope you guys can suggest a great, open source alternative that we overlooked. Regardless of the computer- side control software you use, configure it for a UIR/IRMAN/IRA/CTInfra/Hollywood+ style receiver, and enter the COM port or serial address assigned to it. Our receiver is also compatible with any protocol options like ‘Fast UIR Init’ and ‘Skip UIR Init Check’, which shorten or eliminate the “IR”- > ”OK” handshake. Now test the receiver and add a remote according to the documentation for your software. Manual terminal interface and debugging. If you have a problem with the receiver, or you’re just curious, try to interface it from a serial terminal. We really like the serial terminal on Hercules.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
September 2016
Categories |