Fullscreen HTML5Med Res (??MB)HTML4

A versatile 10-Channel Remote Control Receiver Works with a universal IR remote, either directly or via a UHF radio link This 10-channel control system can be used with any universal IR remote control and can even be controlled via a UHF link so you don’t have to worry about range or high light levels affecting infrared operation. It can be used to switch relays (and other devices) on and off, making it ideal for controlling motors, lights, solenoids, door catches and robots, etc. L ET’S CLEAR UP some confusion right at the start. Most infrared remote controls are intended to control various functions on just one appliance. For example, your TV remote enables you to control all its functions: channel change, volume, mute, picture and so on. By contrast, this 10-Channel Remote Control enables you to use a single infrared remote control to control up to 10 separate devices, turning them on or off. Or you could use it to control more functions on less devices but still using up to 10 buttons on your universal remote. Each channel in the receiver unit has an open-collector output which can drive an external relay, drive one or more LEDs or even directly switch low-power 12V equipment. Each output is initially set as momentary, meaning that the output is only active while you press the relevant button on the remote control. Alternatively, one or more of the outputs can be set to change state (toggle) when you press the relevant button on the remote (ie, each output can be set independently). That means that an output that was previously ON turns OFF (and stays OFF) when its channel button is pressed, while an output that was previously OFF turns ON when its button is pressed. 58  Silicon Chip Each individual toggle output can also be set up to be either ON or OFF when power is applied to the unit. For example, you can set the unit to switch on with Channel 1 OFF, Channel 2 ON, Channel 3 ON and so on. By contrast, the momentary outputs are always all off at power up and their initial switch-on state cannot be altered. An Acknowledge LED indicates whenever a valid remote control signal is received. Presentation The 10-Channel Remote Control Receiver comprises a small box that includes 10 LEDs to indicate the state of each channel. These are labelled from 0-9, corresponding to the 0-9 buttons on the remote control. Each channel has an output that is capable of sinking up to 500mA, so it is suitable for driving a 12V relay or similar load, as indicated above. Power for the unit comes from a 12V DC plugpack supply. The current requirements depend on what sort of load each channel drives. For 12V relays, you could need up to 75mA for each relay but the overall current requirements depend on whether the outputs are set for momentary or toggle operation. If momentary operation for all out- Most universal remote controls can be used with the unit, including the Altronics A1012 (pictured) and the Jaycar AR1726. puts is selected, there will be only one relay on at one time and so a minimum of 85mA is required for the supply, ie, 75mA for the relay and about 10mA for the circuitry. For toggle operation on all outputs, all relays could be switched on at the same time and up to 750mA or so would be needed from the 12V plugpack. The infrared (IR) remote control needs to be a universal type that can be programmed to operate Philips brand or similar appliances. The 10-Channel Remote Control Receiver can operate siliconchip.com.au By JOHN CLARKE using the code for either a TV, a CD player or one or two satellite receivers. Alternative choices are given so that when using the remote to operate the 10-Channel Remote Control Receiver, it does not affect any other appliances you may have. For example, you may find that when the 10-Channel Remote Control Receiver is set to operate using the TV code, your TV also responds. In that case, it’s simply a matter of using one of the alternative codes (ie, for a CD player or satellite receiver). UHF radio link As well as making provision for IR reception, the 10-Channel Remote Control Receiver can alternatively use a 433MHz UHF receiver module. This means that it can be controlled from an IR remote via a UHF radio link – necessary if you don’t have line-of-sight for infrared signals. For this reason, we’re also publishing the circuit details for an “IR To UHF Transceiver” (see the following article). Push a button on your IR remote and the coded IR signal is picked up by this transceiver, converted to a 433MHz radio signal and transmitted to the 10-Channel Remote Control Receiver. Provided you have lineof-sight between the remote and the siliconchip.com.au transceiver, you’re in business – the UHF radio link does the rest. How it works Refer now to Fig.1 for the circuit of the 10-Channel Remote Control Receiver. It’s based on either an infrared receiver (IRD1) or a 433MHz receiver module (RX1), a PIC16F88 microcontroller (IC1) and a couple of ULN2003 Darlington arrays (IC2 & IC3). The mi-   cro decodes the remote control signal codes and drives the channel outputs accordingly. The IR receiver module (IRD1) comprises an IR detector, an amplifier and a demodulator. The demodulator removes the 38kHz infrared modulation of the transmitted signal and the output at pin 1 then comprises the on and off levels that constitute the IR encoding. With no signal, the output remains high at about 5V. The alternative UHF receiver (RX1) receives the UHF signal from the IR To UHF Transceiver and outputs the encoded signal at its Data terminal. This signal is inverted compared to IRD1’s output and so the SET jumper at pin 8 of IC1 is provided to allow either receiver to be selected. When open, the SET input is pulled high (ie, to 5V) via a pull-up resistor inside IC1 and this selects IR signal decoding. Alternatively, when the SET jumper is installed, pin 8 of IC1 is pulled low (0V) and this instructs IC1 to decode a UHF signal. Note that for UHF reception, RX1 is installed but IRD1 must be left off the PCB. Alternatively, for IR reception, you would normally just have IRD1 installed. However, in the latter case, you can actually also mount the UHF receiver on the PCB. That’s because RX1’s output is a high impedance and so would have negligible affect on IRD1’s output. Code links The Code 1 and Code 2 jumpers, Features & Specifications Main Features •  Uses a commercial infrared hand-held transmitter •  10 independent channels •  Momentary or toggle operation •  Selectable output state on power up for toggle selection •  500mA open collector sinking outputs for each channel •  Outputs suitable to directly drive 12V relays •  Infrared or UHF (433MHz) reception •  Acknowledge LED flashes while receiving transmission Specifications Power supply requirements........... 12V at up to 50mA plus current drawn by each output; up to 760mA required for 10 relays if all powered at once Infrared range.......................................................................10m line-of-sight UHF range........................................................................ 30m in open space June 2013  59 DATA 1 LED10 K l A 1k 12 10 11 8 9 14 RB6 RB4 RB5 RB2 RB3 5 Vss RB7 RA6 RA7 RA0 1k 1k 1k 1k 1k 1k 1k 100 mF 16V 1k 1k 1k 1 1B 13 15 16 17 l LED0 K LED1 K l A LED2 K l A LED3 K l A LED4 K l A LED5 K l A LED6 K l A LED7 K LED8 K l A A K 1N5819 l A LED9 K l A 4 4B 2 A 3 3B 3 COM 2C 15 E 8 9 1C 16 ULN2003 E 8 7C 10 6C 11 5C 12 4C 13 3C 14 2C 15 1C 16 ULN2003 100nF 1 2 7C 10 7 7B K A 6C 11 6 6B LEDS 5C 12 5 5B 9 4C 13 4 4B COM 3C 14 3 3B 3 IRD1 +11.8V 2 2B 1 1B IC3 7 7B 6 6B 5 5B 2 2B 6 1 IN IC2 GND 7 RA2 IC1 PIC16F88 18 -I/P RA1 RA3 RA4 RB0 RB1 Vdd 4 MCLR 10-CHANNEL REMOTE CONTROL RECEIVER ACKNOWLEDGE & CODE2 OUT = TV IN, CODE2 OUT = SAT1 OUT, CODE2 IN = SAT2 & CODE2 IN = CD PLAYER GND 433MHz RX MODULE Vcc 2 l 3 10k 100nF OUT REG1 7805 A + OUT 7 – + OUT 8 – + OUT 9 – + OUT 5 – + OUT 6 – + OUT 2 – + OUT 3 – + OUT 4 – + OUT 0 – + OUT 1 – CON2 0V +12V CON1 GND IN OUT 7805 433MHz Rx MODULE 100 mF 16V K D1 1N5819 Fig.1: the circuit uses either an IR receiver (IRD1) or a 433MHz receiver module (RX1) to pick up the remote control signals. These signals are processed by microcontroller IC1 (PIC16F88-I/P) which then drives two ULN2003 Darlington arrays (IC2 & IC3) plus the Acknowledge and channel indicator LEDs. SC Ó2013 CODE1 CODE1 CODE1 CODE1 CODE 2 CODE 1 OPEN = IR CLOSED = UHF SET ANT RX1 IRD1 IR RECEIVER 100 mF 16V +5V ANT GND GND Vcc 100W GND Vcc DATA DATA GND 60  Silicon Chip siliconchip.com.au Par t s Lis t COM (PIN9) OUT IN 2.7k B 7.2k C E B 3k Fig.2: the internal Darlington transistor arrangement for the ULN2003 ICs. There are seven such output driver stages inside each device. C E ONE ULN2003 OUTPUT DRIVER on pins 10 & 11 of IC1 respectively, select the encoding mode, ie, either TV, satellite (SAT1 or SAT2) or CD player. Both the circuit and Table 3 towards the end of the article show the jumper linking options to select each code (eg, leave both jumpers out to select TV encoding). IC1’s RB6 output at pin 12 drives the Acknowledge LED (LED 10). This lights whenever a valid remote control signal, either IR or UHF, is being received. IC1 decodes the remote control signals and provides the 10 channel output signals to drive the Darlington arrays (IC2 & IC3). For example, the channel 0 signal is at RB1 (pin 7) and this drives pin 1 of IC2. Similarly, the channel 1 signal appears at the RB0 output and this drives pin 2 of IC3, and so on for the remaining eight outputs. Note that output channels 0-4 drive IC2, while outputs 5-9 drive IC3. IC2 & IC3 each include seven separate Darlington transistors, with five Darlingtons used in each package to make up the 10 channels. Fig.2 shows the internal Darlington transistor arrangement for each driver. As can be seen, the first NPN transistor is driven via a 2.7kΩ resistor, while its emitter drives the second NPN transistor’s base. The collectors are commoned to provide an output that can sink up to 500mA when the input is driven by 5V (ie, a Darlington arrangement). In addition, a diode clamp is connected between each output and the common pin of the IC. This ensures that the transistors are protected from over-voltage when driving an inductive load. The common pin for the diodes connects to the 11.8V supply. This 11.8V siliconchip.com.au supply is also connected to each of the channel outputs on CON2 (a 20-way screw-terminal block), to provide the positive output terminals. The collector outputs from the Darlington arrays connect to the negative terminals, so that they sink the load current when active. That way, a relay coil can be directly connected to each pair of output terminals, ie, between the +11.8V supply and the individual collector outputs. 5V regulator Power for the circuit is derived from an external 12V supply (eg, a plugpack), with Schottky diode D1 providing reverse polarity protection. The resulting 11.8V rail is then filtered using 100µF and 100nF capacitors and fed to 3-terminal regulator REG1. REG1 then provides a 5V supply rail for IC1, IRD1 and RX1 (the 433MHz receiver module). Note that the supply rail for IRD1 is decoupled via a 100Ω resistor and 100µF capacitor. This minimises supply variations and glitches from being decoded as control signals. In addition, the 11.8V rail at the output of D1 is fed to the positive terminals of CON2, as described above. RC5 codes The Philips RC5 code for infrared transmission is used by many manufacturers including Philips, Marantz, Mission, Grundig and Loewe. The code comprises two start bits and one toggle bit that alternates between high and low on successive same key presses. A five bit address is then sent, followed by six command bits. The bits are sent using bi-phase encoding, whereby a high-to-low transition represents a low bit and a low-to- 1 PCB, code 15106131, 123 x 61mm 1 UB3 box, 130 x 68 x 44mm 1 panel label, 102 x 61mm 11 2-way PCB-mount screw terminals, 5.04mm pitch 1 DIP18 IC socket 1 M3 x 10mm screw 1 M3 nut 3 2-way pin headers with 2.54mm pin spacing 3 pin header jumper shunts 1 170mm length of hook-up wire (UHF version only) 1 2.1mm bulkhead-mount DC socket Semiconductors 1 PIC16F88-I/P microcontroller programmed with 1510613A. hex (IC1) 2 ULN2003 Darlington arrays (IC2,IC3) 1 infrared receiver (TOSOP4136 or similar) (IRD1) or 1 433MHz receiver (Jaycar ZW-3102, Altronics Z 6905A) (RX1) 1 7805 5V regulator (REG1) 1 1N5819 1A Schottky diode (D1) 10 3mm red high-brightness LEDs (LED0-LED9) 1 3mm blue high-brightness LED (LED10) Capacitors 3 100µF 16V PC electrolytic 2 100nF MKT polyester Resistors (0.25W, 1%) 1 10kΩ 1 100Ω 11 1kΩ Miscellaneous Cable glands, hook-up wire high transition a high bit. The data is transmitted at a 1.778ms rate, with the whole code taking at 24.889ms to send. The next code starts after 113.778ms. As stated above, the RC5 remote control signal, either from IRD1 or RX1, is decoded by IC1. Building it Take a look now at Fig.3 for the assembly details of the 10-Channel Remote Control Receiver. It’s built on a PCB coded 15106131 (123 x 61mm) and this clips neatly into a plastic utility case measuring 130 x 68 x 44mm. Install the resistors and diode D1 first. Table 1 shows the resistor colour June 2013  61 115106131 3160151 C 2013 + OUT0 + OUT1 + OUT2 + OUT3 + OUT4 10-CHANNEL REVIE CE REMOTE R ET O ME RECEIVER R LE N NA H C- 0 1 + OUT5 + OUT6 + OUT7 +OUT9 + OUT8 GND DATA 2 100W 1k 1k 1k CODE 1 1k RX1 IC3 ULN2003 100 mF 100nF SEE NOTE 2 0V IC1 PIC16F88-I/P 10k 1k 1k 1k SET CON1 +12V 1k 100 mF 1k 5819 IC2 ULN2003 D1 433MHz Rx MODULE 100nF 1k REG1 7805 DATA Vcc 100 mF 1k CON2 Vcc GND GND ANT ANT. ACK. A LED0 LED1 LED2 LED3 LED4 LED5 NOTE 1: INSTALL IRD1 OR RX1 (NOT BOTH); ‘SET’ JUMPER = OPEN FOR IRD1, CLOSED FOR RX1 LED6 LED7 LED8 LED9 LED10 IRD1 NOTE 2: SOLDER A 170mm ANTENNA TO ‘ANT’ TERMINAL IF RX1 INSTALLED Fig.3: follow this layout diagram to install the parts on the PCB. Note that either IRD1 or RX1 is installed but not both (see text). You will need to solder a 170mmlong antenna to the ‘ANT’ terminal if RX1 (the UHF module) is used. codes but you should also check each one using a digital multimeter before soldering it into place. Make sure the diode is installed with the correct polarity, with the banded end orientated as shown on the layout diagram. Once these parts are in, REG1 can be fitted. It’s mounted horizontally on the PCB, with its leads bent down through 90° so that they go through their respective holes. Secure its metal tab to the PCB using an M3 x 10mm machine screw and nut before soldering its leads (note: don’t solder the leads first, otherwise the PCB tracks could fracture as the nut is tightened). Follow with the three 2-way pin headers for the SET, Code 1 & Code 2 jumpers, then install an 18-pin IC socket for IC1 (be sure to position the notched end as shown). You can also install sockets for IC2 & IC3 if you wish but these are optional. If you don’t wish to use sockets, these two devices can now be directly soldered to the PCB, with their notched ends facing towards REG1. Do not insert IC1 into its socket yet – that step comes later, after you’ve checked the 5V supply rail. The capacitors are next on the list. The two 100nF capacitors can go in either way around but be sure to install the three 100µF electrolytics with the correct polarity. The 20-way screw terminal block (CON2) can now be installed. It’s made up by dovetailing 10 2-way blocks together and must be fitted with the wire entry holes facing outwards. Push it all the way down so that it sits flush against the PCB before soldering the terminals. Once it’s in, the 2-way terminal block (CON1) can be fitted at lower left. Right: the prototype PCB, ready for installation in the case. Note how the LEDs are all stood off the board (on 25mm lead lengths) so that they later protrude through the holes in the case lid. Our prototype used red LEDs for LEDs0-9 and a blue LED for LED10 (Acknowledge) but any colour can be used. IR/UHF receiver module The PCB assembly can now be completed by installing either the infrared receiver (IRD1) or the UHF receiver (RX1) and configuring the SET jumper. Install IRD1 and leave the SET jumper out if you want to use infrared signals to control the 10-channel receiver. It goes in with its lens facing the adjacent edge of the PCB and is installed with its leads left at full length so it can later be pushed into position to align with its case hole. Alternatively, install RX1 and fit the SET jumper if you want to control the receiver using a 433MHz UHF radio link. RX1 must be orientated with its component side to the right. In addition, a 170mm-length of hook-up wire must be soldered to the antenna (ANT) terminal to pick up the 433MHz signal. Don’t also install IRD1 if you intend using the 433MHz transceiver (RX1), as this would upset the latter’s opera- Installing the LEDs Now for the LEDs. These must be installed so that the top of each LED is exactly 30mm above the PCB surface, which means mounting them with 25mm lead lengths. The easiest way to do this is to use a 25mm wide strip of cardboard as a spacer. It’s just a matter of pushing each LED down onto this strip (ie, leads on either side) before soldering it to the PCB. Be sure to orientate each LED correctly, with the longer anode leads to the left. Table 1: Resistor Colour Codes   o o o o   No.     1  11     1 62  Silicon Chip Value 10kΩ 1kΩ 100Ω 4-Band Code (1%) brown black orange brown brown black red brown brown black brown brown 5-Band Code (1%) brown black black red brown brown black black brown brown brown black black black brown siliconchip.com.au NB: this prototype PCB shows both IRD1 and RX1 in place. In practice, only one of these is normally installed. tion. Conversely, you can fit both IRD1 and RX1 if you intend using IRD1 to pick up the remote control codes, as explained previously. You might want to do that if you intend swapping over and using RX1 at some later date (in which case you would then have to remove IRD1). Final assembly Before installing the PCB in the case, you will need to drill holes in the rear of the base for the DC power socket, plus holes to accept two cable glands. The cable glands route and secure the various leads from the output terminals on CON2. The DC socket hole should be drilled in one end of the case, ie, near CON1 on the PCB. It should be centred horizontally and positioned about 12mm down from the top of the base. Use a small pilot drill to drill this hole first, then carefully enlarge it to size with a tapered reamer until the socket is a neat fit. The two cable gland hole centres are exactly 14mm down from the top of the base and must be centred between the two sets of vertical rib pairs. Drill these holes using a pilot drill initially, then enlarge them to 12mm using a tapered reamer. In addition, a 4mm hole must be drilled in the front of the base in-line with IRD1’s lens. This hole is position 22mm in from the adjacent side (as measured at the top of the base) and 11mm down. A row of 11 3mm holes is also required along one edge of the lid to accept the LEDs. These holes can be drilled using the front panel artwork as a template. This artwork can be downloaded from the SILICON CHIP website at www.siliconchip.com.au (select “Shop” and then “Panel artwork”) and temporarily attached to the lid using tape. After drilling, clean up the holes using an oversize drill, then print out another copy of the artwork onto photo paper and attach it to the lid using silicone sealant (or some other suitable adhesive). Once the silicone has cured, the holes for the LEDs can either be punched out or cut out using a sharp hobby knife. The assembly can now be completed by clipping the PCB into place, fitting the cable glands and the DC socket and running the positive and negative supply leads between the DC socket The PCB clips into the integral slots in the sides of the UB3 case. You need to drill holes in the rear edge for two cable glands, a hole in the front edge for the IR receiver (if used) and a hole in the lefthand end for the DC socket. Eleven holes are also required in the lid for the LEDs. siliconchip.com.au June 2013  63 Table 2: Link Selections For Infrared Device Link TV SAT1 SAT2 CD Player CODE1 Out In Out In CODE2 Out Out In In The remote control coding will have to be set up before the unit is used. This involves installing the Code links on the PCB (see Table 1) and setting up the remote to suit (see text). is incorrect, switch off immediately and check the supply polarity, the orientation of diode D1 and the 7805 regulator. If the reading is correct, switch off and install IC1 in its socket. Make sure that this device is orientated correctly and that all its pins go into the socket. IC2 & IC3 should also now be installed if you are also using sockets for these devices. This close-up view shows how the DC socket is wired to screw-terminal block CON1. and CON1. It’s also necessary to bend IRD1’s leads so that its lens is aligned with its hole in the side of the case. Initial checks Now for the smoke test. Check the assembly carefully, then connect a 12V DC plugpack, switch on and measure the voltage between pins 5 & 14 of IC1’s socket. You should get a reading of between 4.85V and 5.15V. If this Remote control coding Before testing, you will need to set up the remote control coding. The first step is to decide whether you will be using a TV, satellite or CD player code on the remote, then configuring the jumpers on the 10-Channel Remote Control Receiver accordingly – see Table 1. Omitting both the CODE1 & CODE2 jumpers selects the TV code; installing the CODE1 jumper only selects SAT1; installing the CODE2 jumper only selects SAT2; and installing both jumpers selects the CD player code. That done, the correct code must now be programmed into the remote. This involves selecting TV, SAT1, SAT2 or CD on the remote (to agree with the 10-Channel Receiver) and then programming in a 3-digit or 4-digit number for a Philips device. Most universal remote controls can be used, including the Altronics A1012 and the Jaycar AR1726. For the Altronics A1012, use a code of 023 for TV mode, 242 for SAT1, 035 for SAT2 or 083 for a CD player. Similarly, for the Jaycar AR1726, use 103 for TV, 1317 for SAT1 or 1316 for SAT2. In the case of other universal remotes, it’s just a matter of testing the various codes until you find one that works. There are usually no more than 15 codes (and usually a lot less) listed for each Philips device, so it shouldn’t take long to find the correct one. Note that some remotes may only work in one mode (eg, TV but not SAT). For example, if you have a Digitor Darlington Saturation Voltage In The ULN2003 Devices According to the ULN2003 data sheet, the output saturation voltage of each Darlington output stage is typically 1.3V <at> 350mA (but can be as high as 1.6V). And it’s typically 1.1V <at> 200mA and 0.9V <at> 100mA. This means that with a supply of exactly 12V and a load drawing 350mA, the load will typically see just 12V - 1.3V - 0.2V (the Schottky diode voltage) = 10.5V. And it 64  Silicon Chip could be less than that depending on how much current other channels are drawing, the temperature and so on. As a result, the Darlington configuration results in a voltage across the load that’s substantially below the 12V supply voltage and while most 12V relays will happily run off 10.5V, other loads such as 12V LEDs may not. In fact, 12V LED lamps and 12V LED strips would probably be quite dim if switched using this unit because of the Darlington saturation voltage. This can be slightly improved if the positive power supply terminal of each load is connected directly to the 12V supply, ie, bypassing D1. And, in fact, this will be necessary if the load total exceeds 1A, as D1 is only rated as 1A DC. siliconchip.com.au OUT + RELAY 1 OUT + RELAY 2 OUTPUT A OUT - 390Ω OUT + A OUTPUT B NO NC NC OUT - NO λ LED K OUT - Fig.4(b): driving a LED output. MOTOR + VOLTAGE TO SUIT MOTOR Fig.4(a): using two outputs to drive a motor in forward & reverse: (1) Both outputs set for momentary operation. In this case, pressing (and holding) the button for Output ‘A’ activates Relay 1 and causes to the motor to rotate one way, while pressing the button for output ‘B’ activates Relay 2 and causes the motor to rotate the other way. (2) Both outputs set for toggle operation. If both outputs are off at power-up, the motor will be stopped until one of the outputs is toggled (its direction will depend on which output is turned on). Alternatively, if one output is high and the other low at power-up, then the motor will run as soon as power is applied. The motor can be stopped and reversed by toggling the outputs. (3) One output momentary and the other toggle. If the toggle output is high at power-up, the motor will immediately run. It can be stopped temporarily by pressing the button for the momentary output, or stopped permanently by pressing the button for the toggle output. Table 3: Setting The Outputs For Momentary Or Toggle Operation Step 1 Step 2 Step 3 (Toggle Operation Only) Press Channel Up, then press Press “0” for momentary Press “0” for output off at power channel number to set operation or “1” for toggle up, “1” for output on 4-in-1 remote, you can use 5005 for TV1 but there’s no suitable code for SAT. Similarly, if you have an AIFA RA7, you can use 026 for TV1 but again there’s no suitable code for SAT. If you are using infrared reception (ie, IRD1 installed), the receiver should now respond to the channel number buttons on the remote. When you press a button, the Acknowledge (ACK) LED should flash (to indicate that code is being received) and the indicator LED for that channel should light. As mentioned, the 10-Channel Remote Control Receiver is initially set so that its outputs are momentary in operation. That means that a channel indicator LED should only light while its corresponding button on the remote is held down and should go out as soon as the button is released. If it doesn’t operate, check that IRD’s lens is aligned with its hole in the case. Check also that the code programmed into the universal remote is correct and check that the SET input is open, ie, no jumper installed. Note that the jumpers on the SET, CODE1 & CODE2 headers are only checked by the microcontroller at siliconchip.com.au power up. So changing these jumpers with the power on will have no effect on the operation until the power is switched off and then on again. Momentary or toggle You can easily change one or more outputs to toggle operation to suit your particular application. In this operation mode, an output changes state when its remote button is pressed and remains in that state until the button is pressed again. The output configuration is done using the hand-held remote. First, press the Channel Up (CH +) button and check that the Acknowledge LED on the receiver stays lit. Then press the number for the channel you wish to program. After that, pressing “1” will select toggle operation for that channel, while pressing “0” will select momentary. If momentary operation is selected, the Acknowledge LED OUT + 390Ω 1 4N28 OPTOCOUPLER 5 λ OUT - 4 2 Fig.4(c): driving an optocoupler. OUT + 12V RELAY OUT - NO C NC Fig.4(d): driving a 12V relay. will extinguish and the setting will immediately be stored. If toggle operation (1) is selected, then you need to enter an additional number – either “0” or “1” – to select the state of the output at power up. A “0” sets the output to off at power up, while “1” will sets the output to on. Once you have entered this number, the Acknowledge LED will extinguish and the settings will be stored. This procedure must then be repeated for any additional channels that require changing. Note that the Channel Down (CH-) button can be pressed before all the numbers are entered to exit the channel programming. There will be no change to the setting if this is done. In addition, the numbers for each setting must be entered within 12s, otherwise the program in the PIC micro will exit without making any changes. Finally, Figs.4(a)-4(d) show how to use the outputs to drive various devices, including a 12V DC motor in forward or reverse. Note that while Fig.4(b) shows how to drive a single LED, it’s also possible to drive series or parallel LEDs – just adjust the value of the current-limiting resistor SC accordingly. Extending The Range Of The Remote Control Want to extend the remote control range or want it to operate without line of sight? You can with the IR To UHF Transceiver described on the following pages. June 2013  65