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Infrared Remote Control
Assistant
Remote controls are handy, but sometimes equipment makes their
use quite clunky. Selecting between live TV, DVD/Blu-ray, pay-TV
and internet streaming on a television often requires you to press
several different buttons in sequence. Now, these sequences can be
performed at the press of a single button using the Infrared Remote
Control Assistant.
By John Clarke
I
t’s even more annoying when the multiple steps require
the use of more than one remote control.
If you have several sources connected to your TV,
you may need to open the ‘source’ menu and use the up
or down or left and right buttons on its remote control to
select the source and then press ‘Enter’ to select that input.
There can be even more presses involved to access internet streaming such as from SBS On Demand and ABC iview.
This may be OK for you (you probably set the TV up!),
but your spouse, parents and friends probably don’t appreciate the complexity, and may well not be able to figure out how to do this.
The IR Remote Control Assistant helps solve this. It vastly
simplifies the procedures by recording the sequence and
then replaying it whenever a button is pressed.
It isn’t useful just for these complex remote control sequences either. It can also perform the same task as a single button press on multiple remotes, so you can perform
common tasks without having to go to the device’s specific
remote control.
For example, you might want to set up the IR Remote
Control Assistant to provide volume control as well as handling complex sequences.
What about learning remotes?
Many universal remote controls have a learning function, but they are designed to provide a single function
for each button switch. They can’t store a long sequence
of infrared codes.
With the IR Remote Control Assistant, there are eight
push button switches and each can be used to store separate
infrared remote control sequence procedures in memory.
It not only stores the codes required in the right sequence,
but also the delay between each button press.
This may be important as some sequences require you
to wait until the device is ready to proceed with more button presses.
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Silicon Chip
It can typically store up to 100 separate remote control
codes in each sequence (ie, up to 800 codes total). Sequences can run for up to about two and a half minutes,
although the total time may be reduced if there are many
complex codes involved.
For example, for ten typical button presses, the maximum
sequence time is two minutes and 36 seconds but for 50,
it drops to about one minute and 20 seconds.
In practice, you’re unlikely to require a code sequence
so long in either number of codes or time duration that you
run out of memory. And the unit can record eight separate
sequences; each is allocated its own memory space.
Presentation
The IR Remote Control Assistant is housed in a remote
control case that has a separate battery compartment. The
eight sequence pushbuttons are on top, while at the front
is the infrared (IR) LED that sends the codes to the TV or
other device.
There is also an IR receiver used to receive the infrared
codes for recording sequences.
A small switch is included to select between the record
or play mode, while a visible-light LED indicates operation.
The IR Remote Control Assistant is easy to use. Once it has
been programmed, just press one of the eight pushbuttons
to replay a stored IR sequence. The LED indicator flashes
in response to the code being sent. While the IR Remote
Control Assistant is playing back an infrared sequence, it
can be stopped by pressing any button.
Programming sequences is also quite easy; this is described below, after the construction section.
Circuit description
The full circuit is shown in Fig.1. It’s based around 8-bit
microcontroller IC1, which is the electronic ‘brains’ behind
the IR Remote Control Assistant. While we’ve often used
the PIC16F88 in the past, that part is now no longer rec-
Australia’s electronics magazine
siliconchip.com.au
Features & specifications
•
•
•
•
•
•
•
•
•
•
•
•
Deep memory storage
666.66ns sampling resolution
Eight separate independent
selections available
Up to 100 separate IR code storage
possible per procedure
174s (2m 54s) maximum record
time per procedure
34.4kHz to 41.66kHz modulation
adjustment range, in 15 steps
Easy learning or record function
Automatic memory erase before
recording on each selection
Bulk erase of all eight selections
available
Indicator LED
Adjustable infrared modulation
frequency
Battery powered, with low
standby current (3.3µA typical)
ommended for new designs and is becoming more expensive. The PIC16F1459 has a lot more features but despite
that, it is cheaper.
IC1 stores the programmed code sequences in 1Mbit serial RAM chip IC2. Remote control codes from other devices are picked up by infrared receiver IRR1 and
fed straight to the RA5 digital input of IC1 (pin
2). IRR1’s 5V power supply is switched by Mosfet
Q1 and filtered using a 47W series resistor and
10µF bypass capacitor, to provide clean power
to IRR1; it is sensitive to supply noise.
Mosfet Q1’s gate is driven directly from the
RC4 digital output of IC1 (pin 6). As Q1 is a Pchannel Mosfet, IRR1 is powered when pin 6
is low, and switched off to save power when
pin 6 is high.
When transmitting infrared remote control code sequences, IC1 drives its RC5 digital output (pin 5) high. This forward-biases
NPN transistor Q3’s base-emitter junction,
with the current limited to a few milliamps
by its 1kΩbase resistor.
When switched on, Q3 sinks about 25mA
from the cathode of infrared LED1. It does
this in pulses, so the average LED current
is less than 10mA during pulses and less
if averaged over the whole transmission.
The RC5 output is a pulse width modulated (PWM) output running at close to
a 32% duty cycle.
Trimpot VR1 adjusts the modulation
frequency for infrared LED1. The voltage
at its wiper is converted to a digital value at
the AN8 analog input of IC1 (pin 8). After processing, this value provides a modulation frequency for RC5
between 34.4kHz when fully anticlockwise and 41.66kHz
when fully clockwise.
siliconchip.com.au
Infrared remote controls tend to use a frequency of either 36kHz, 38kHz or 40kHz. The adjustment is provided
to obtain the best results during use. Typically, setting the
frequency to 38kHz (mid-position of VR1) will suit all IR
receivers, provided the Assistant is reasonably close to the
receiver. More range might be available at a different
frequency setting selected with VR1.
The LED indicator (LED2) lights
up in response to the IR code
during the recording of infrared
signals and as a sending data indicator when replaying infrared
signals. It is driven via the RC3
output (pin 7) via a 1kΩ resistor.
The RC3 output also powers up
one side of VR1 when set high,
saving 0.5mA the rest of the time.
Button sensing
Pushbutton switches S1-S9 are
connected in a 3 x 3 matrix with the
RC0, RC1 and RC2 outputs (pins 16,
15 & 14) connecting to one side of the
switches and the RA1, RA4 and RA0
inputs (pins 18, 3 & 19) connecting to
the other side.
Note that RA1 and RA0 have 100kΩ
pull-up resistors to the 3.3V supply, but
RA4 does not. That’s because the RA4
input of IC1 can be configured with an
internal pull-up to 5V, via the software.
The reason that RA1 and RA0 do not
have this feature is that on this chip, they
can also be used as the USB D+ and D- signal lines. These pins thus operate somewhat
differently from other I/O pins when USB mode is disabled.
Their pull-ups are designed to suit the USB specifications
Australia’s electronics magazine
July 2020 77
rather than be used as general-purpose pull-ups.
The reason that the 100kΩ resistors go to the 3.3V rail
rather than the 5V rail is that these USB-specific pull-ups
are implemented via internal P-channel Mosfets within
IC1, and their sources connect to the +3.3V rail. So if we
pulled these pins up to +5V then the 3.3V supply voltage
would rise, as the intrinsic reverse diodes in these P-channel Mosfets would conduct.
That would cause the 3.3V supply to rise to around 4.7V.
That usually would not be a problem, but we use the 3.3V
supply to provide memory backup for IC2. And as we shall
see later, this voltage is already near the maximum allowed
for that purpose.
That leaves us with the question of whether 3.3V is sufficient for the RA0 and RA1 inputs to differentiate between
high and low levels. It turns out that the minimum voltage
that is guaranteed to be detected as a high level for these
pins is Vdd ÷ 4 + 0.8V, which for the highest possible Vdd
of 5.15V, is still less than 2.1V. So the pull-ups to the 3.3V
rail work fine.
To detect if any switch is closed, all RC0, RC1 and RC2
outputs are taken low in sequence. The RA1, RA4 and RA0
inputs will typically be high due to the pull-ups. However,
one input will be held low if a switch is pressed. The combination of which of the three sets of pins are low tells us
which button was pressed.
Note that if more than one switch is pressed at a time,
then the first detected closed switch will be the one that’s
deemed to be closed. When we require two switches to be
closed, such as when clearing memory for an individual
switch, switch S9 (the Mode switch) is checked for closure
independently from the other switches.
ing until the gate is held fully low. The reason we do this
is so that IC1 does not reset due to a momentary drop in
its supply voltage, which can happen if IRR1 is instantly
switched on, due to its 10µF bypass capacitor and the limited current that can be supplied by the 9V battery.
Once powered, IRR1 is ready to receive IR codes. Most
infrared controllers use a modulation frequency of 3640kHz. This is done in bursts (pulses), with the length of
and space between the bursts (pauses) indicating a code.
The series of bursts and pauses are usually in a particular format (or protocol), and there are several different protocols commonly used.
This includes the Manchester-encoded RC5 protocol
originated by Philips. There is also the Pulse Width Protocol used by Sony and Pulse Distance Protocol, originating from NEC.
If you are interested in details on all these protocols
and others, see the article in SILICON CHIP from June 2019
on the Steering Wheel Audio Button to Infrared Adaptor
(siliconchip.com.au/Article/11669).
The output from IRR1 is a demodulated version of the
infrared signal, which is high (5V) when there is no signal
and low (near 0V) when a 36-40kHz modulated burst is
detected. We record the level and duration of each pulse
to memory when recording. The recorded sequence is reproduced during playback by modulating LED1 in bursts.
It is driven as described above.
Memory
As described earlier, infrared receiver IRR1 is used for
recording the infrared code and its power is controlled by
Mosfet Q1. Before recording, the supply voltage for IRR1
is increased slowly to 5V over 13 milliseconds.
This is done by applying brief low pulses (2/3ns long) to
its gate, with a repetition rate starting at 66µs and reduc-
The memory chip is a 1024kbit (1Mbit) memory organised as 128kbytes. The memory is accessed over a simple
Serial Peripheral Interface (SPI) bus. When writing, data
is sent to the SI input of IC2 (pin 5) from the SDO (pin 9)
output of IC1. When reading, data is received from the SO
output of IC2 (pin 2) to the SDI input (pin 13) of IC1.
In both cases, the data is clocked using the signal from
the SCK (pin 11) of IC1 to the SCK input of IC2, at pin 6.
Communication with IC2 is enabled by a low level at the
chip select (CS), driven from pin 10 of IC1 (RB7) and sensed
at pin 1 of IC2.
Scope1: this shows the modulation of the infrared signal
from pin 5 of IC1. This drives transistor Q3 which controls
infrared LED1. The modulation frequency is around
38.5kHz, as VR1 is set mid-way. VR1 can be used to set
the frequency from 34.4kHz to 41.66kHz. The duty cycle is
fixed at about 32%.
Scope2: the top trace is a capture of an infrared signal,
measured at the pin 1 output of IRR1. The lower trace
shows the output at pin 5 of IC1 after that infrared coded
signal shown in the top trace was stored in memory and
replayed, which is shown inverted and also modulated at
34.4kHz.
Recording
78
Silicon Chip
Australia’s electronics magazine
siliconchip.com.au
S
Q1
NTR4101
PTG
A
TRANSMIT
D
1k
1 F
1 F
CERAMIC
100nF
(INFRARED)
CERAMIC
9V
BATTERY
+5V
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6
3
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1
4
10 F
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RA3 /MCLR
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FREQUENCY
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10k
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100k
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100k
CERAMIC
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MCP1703
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BC 33 7
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TAB (GND)
IR REMOTE CONTROL ASSISTANT
A
Q2
NTR4101
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100nF
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Vss
20
2020
A
GND
10 F
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RECEIVE
SC
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IRR1
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INDICATOR
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+5V
+5V
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2
3
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Fig.1: the circuit of the Assistant is not too complicated. It’s based around microcontroller IC1 which records infrared
pulses sensed by receiver IRR1 into RAM chip IC2. It can later read these back and reproduce them by flashing
infrared LED1 via transistor Q3, when triggered by a press of button S1-S8.
When writing to memory (after power is applied via Q2),
the memory is selected by bringing the chip select input
low. Then a write instruction is sent, followed by the desired memory address from which to start. This is a 24-bit
address sent as three 8-bit bytes. The seven most significant address bits are always zero, since only 17 bits are required to address the 128k bytes.
Following this, data can be written. The memory powers up in sequential mode where the address automatically
increments after each byte is written.
The signal from IRR1 consists of a series of high and low
levels. These levels are monitored at a fast rate, but we don’t
store each sampled level directly into memory. That would
chew up the memory too quickly. For example, sampling
at a rate of 1.5MHz (ie, each 2/3µs) and storing that level
in successive bits, the entire 1Mbit of memory would be
full after 2/3 of a second!
So instead, we sample the level each 666.66ns, but we
don’t store this directly in memory. Instead, we continue
siliconchip.com.au
to monitor the level and record how long it remains at the
same level before changing. The level and duration of each
pulse are stored every time the level changes.
To store this, we use two consecutive 8-bit address locations (16 bits total). The most significant bit (bit 15) stores
the level while the remaining 15 bits are used to store the
length of the pulse, in 666.66ns intervals.
The maximum value we can store in 15 bits is 32,768,
so the maximum period stored in each 16-bit memory location is 32,768 x 666.66ns, or 21.845ms. If the data level
does not change within the maximum period, we continue
storing the duration of that same level into the next 16-bit
wide memory slot. This is a form of ‘run-length encoding’
data compression.
For our project, we further divide up the memory into
eight separate 16kbyte blocks. So the first 16kbyte block is
reserved for the sequence stored using switch 1, the second 16kbyte block is for switch 2 and so on, up to switch
8 for the last 16kbyte block.
Australia’s electronics magazine
July 2020 79
NTR4101
1 F 1 F
D1
5819
REG1
MCP1703-5002E/DB
ra cyaJ
Jaycar Version
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Silicon Chip
The 100µF capacitor is only discharged through leakage in the capacitor itself and via discharge at VBAT , at
around 1µA.
Power
The circuitry is powered from a 9V
battery that is regulated down to 5V
using an ultra-low quiescent current
regulator that typically only draws
2µA at low output currents. Reverse
polarity protection is via schottky diode D1. There are two 1µF ceramic bypass capacitors, one at the input and
one at the output of the regulator for
supply decoupling and to ensuring
regulator stability.
The 5V supply is also bypassed with
a 10µF electrolytic capacitor and a
100nF capacitor near IC1.
Saving power
Since we are powering the IR assistant from a battery, power draw needs
to be minimised. This is done by only
powering parts when they are needed
and placing IC1 in a sleep state unless
it is required to record or play infrared code. In sleep mode, IC1 typically
draws just 0.3µA. IC1 is woken from
sleep when a switch is pressed.
Other parts powered off include the
Australia’s electronics magazine
100nF
S3
100k
D2
47k
IC1
S2
S1
S4
S5
100k
4148
PIC16F1459
1k
FREQUENCY
VR1 10k
S6
Q2
1
IC2
NTR4101
23LCV1024
100 F
10 F
+
9V
–
9 V BATTERY
To read the stored data, the CS input
of the memory is taken high and then
low again to select the memory, and
the read instruction is sent along with
the 24-bit address location. Then the
data is read out in sequence.
Power for IC2 is switched on or off
via another P-channel Mosfet, Q2. This
conserves power as the IR Remote Sequencer will be sitting dormant most
of the time, so it makes sense to power
off the memory. It draws around 3mA
when active, but only 4µA in standby.
Data stored in the memory is maintained when power is removed from
IC2 by supplying a voltage to the battery backup (VBAT ) at pin 7. This derives
power from the 3.3V supply from the
internal 3.3V regulator in IC1 that’s
intended to power its USB peripheral. This is available at the VUSB3V3 pin,
pin 17. The voltage range for VBAT is
1.4-3.6V, so this 3.3V supply (3.0-3.6V
tolerance range) is ideal.
Power for VBAT is applied via D2 and
a series 47kΩ resistor. A 100µF lowleakage capacitor holds power to VBAT
for a substantial period (more than
100s) during the period while the battery is changed. D2 diode isolates VBAT
from the 3.3V supply that will drop to
zero when the battery is disconnected.
S9 MODE
(UNDER)
10 F
47
S8
S7
1k
S6
1
1k
S5
Q2
100 F
Q1
Q3
C 2020
15005202
NTR4101
BC337
Rev.B
100nF
100nF
47k
IC1
S4
1 F SMD
CERAMIC
CAPACITOR
ON
UNDERSIDE
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1
23LCV1024
10 F
S3
100k
4148
PIC16F1459
1k
1k
FREQUENCY
100nF
IC2
D2
IRR1
150
S2
100nF
1
100nF
S1
NTR4101
100k
15005201
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Rev.B
A
A
LED2 (UNDER) LED1(UNDER)
S9 MODE
10 F
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Q3
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TSOP4136
IR REMOTE ASSISTANT
A
LED1
LED2
150
VR1 10k
Fig.3 (right): this is the
PCB overlay diagram for
the version which fits
into an Altronics remote
control case. Construction
is similar to the PCB
shown in Fig.2, except
that LED1, LED2, S9 and
IRR1 are mounted on the
other side of the board,
and IRR1’s leads are
cranked differently.
TSOP4136
IRR1
A
IR REMOTE ASSISTANT
1k
Fig.2 (left): use this PCB
overlay diagram as a
guide when building the
version of the Assistant
that fits into a Jaycar
remote control case. Start
assembly with the SMDs:
IC2, Q1-Q2, REG1 and
the three 1µF ceramic
capacitors. Watch the
orientations of IC1, IC2,
D1, D2, LED1, LED2,
Q3 and the electrolytic
capacitors.
1 F 1 F
S7
D1
5819
REG1
MCP1703-5002E/DB
S8
+
9V
–
s cinortlA
9 V BATTERY
Altronics Version
infrared receiver (IRR1), memory chip
IC2, indicator LED2 and trimpot VR1.
Overall current drain in standby is
thus 0.3µA for IC1 plus 1µA for IC2’s
VBAT input and 2µA for regulator REG1.
This is about 3.3µA total, although we
measured 2.7µA on our prototype. If
the IR Remote Control Assistant is
used for one minute per day, that adds
about an average of 7µA current draw
over the day.
Assuming a conservative 400mAh
capacity for a 9V alkaline battery, we
can expect the battery to last four years.
That’s almost the shelf life of the battery itself, which would typically be
five years. More frequent usage of the
IR Remote Control Assistant will reduce the battery life a little.
Construction
The IR Remote Control Assistant is
housed in a remote control case and
built on a double-sided PCB.
We’ve designed two different PCBs
to suit different remote control cases.
For the Jaycar HB-5610 remote control
case, the PCB is coded 15005201 and
measures 63.5mm x 86mm. The PCB
coded 15005202 and measuring 58.5
x 86mm suits two Altronics cases, either H0342 (Grey) or H0343 (Black).
siliconchip.com.au
stalled, and these must be mounted
with the orientations as shown. Note
that D1 is a 1N5819 type while D2 is
a smaller 1N4148.
It’s a good idea to mount IC1 using an IC socket. When installing the
socket, take care to orientate it correctly. Its notch should be positioned
as shown. Then fit trimpot VR1 and
transistor Q3.
The capacitors can go in next,
with the electrolytic types orientated with the polarities shown (the
longer lead is positive). Make sure
these capacitors are fitted so that
their height above the PCB is no more
than 12.5mm; otherwise, the case lid
may not fit.
Parts varied by version
LED1, LED2, IRR1 and pushbutton
This same-size photo matches the Jaycar
PCB layout opposite (Fig.2) but the
Altronics version (Fig.3) is virtually
identical, albeit on a slightly narrower
PCB. Make sure the battery wiring is
threaded through the strain relief holes,
as shown here and on the diagrams.
A panel label attaches to the front
face of the box in each case, so you
know what the unit and its controls do.
Select the correct PCB to suit your
case and refer to the relevant PCB overlay diagram: Fig.2 for the Jaycar case
or Fig.3 for the Altronics case.
Start assembly by soldering IC2 in
place. This is a surface-mounting device, best fitted by placing it in the correct position and soldering one of the
corner pins to the PCB pad. Check that
the IC is aligned and orientated correctly before soldering the remaining
pins. If it is not aligned, remelt the solder on the pin and align the IC again.
Any solder bridges between the
leads can be cleared using solder wick
to draw up excess solder. Solder wick
works best when a little flux paste is
applied to the bridge first.
Fit Q1, Q2, REG1 and the three 1µF
ceramic capacitors next, using a similar technique. Two of the capacitors
are near REG1 while the other is on
the opposite side of the PCB, underneath IC1.
Install the resistors next. You can
read the resistor colour code to figure
out the resistor values, but it’s best to
use a digital multimeter to measure
each value. The diodes can then be insiliconchip.com.au
S9 are mounted differently depending on the version you are building.
For the version that fits into the Jaycar case, these parts mount on the top
side of the PCB.
Bend LED2’s leads down by 90°,
6mm back from the base of its lens,
making sure the anode lead is to the
left. The LED then sits horizontally
with the centre of the lens 6mm above
the top of the PCB.
Similarly, LED1 mounts horizontally 6mm above the PCB, except its
leads should be bent some 4mm back
from the lens base, again ensure that
the anode is to the left. IRR1 is also
mounted with the centre of its lens
6mm above the PCB. Bend its leads in
a dog-leg shape, so the front of its lens
lines up with the LED lenses.
For the Altronics version, LED1,
Parts list – IR Remote Control Assistant
1 panel label (see text)
1 20-pin DIL IC socket
8 click action pushbutton switches, any colours (S1-S8)
[eg, Jaycar SP0720-4, Altronics S1094-1099]
1 right-angle (RA) tactile pushbutton switch (S9) [Jaycar SP0604]
1 9V battery
1 9V battery clip lead
Semiconductors
1 PIC16F1459-I/P microcontroller programmed with 1500520A.hex, DIP-20 (IC1)
1 23LCV1024-I/SN static RAM, SOIC-8 (IC2) [RS Components 803-2181]
1 MCP1703-5002E/DB 5V ultra-low quiescent current regulator, SOT-23 (REG1)
[RS Components 669-4890]
2 NTR4101PT1G P-channel Mosfets, SOT-23 (Q1,Q2) [RS Components 688-9152]
1 BC337 NPN transistor (Q3)
1 TSOP4136 IR receiver (IRR1) [Jaycar ZD1953]
1 5mm IR LED (LED1)
1 3mm red LED (LED2)
1 IN5819 1A schottky diode (D1)
1 1N4148 signal diode (D2)
Capacitors
1 100µF 16V low-leakage (LL) PC electrolytic
2 10µF 16V PC electrolytic
3 1µF 16V X7R SMD ceramic, 3216/1206 size
3 100nF MKT polyester
Resistors (all 1/4W 1% metal film)
2 100k 1 47k 3 1k
1 150 1 47
1 10k mini top-adjust trimpot (5mm pin spacing) (VR1)
Extra parts for Jaycar version
1 70 x 135 x 24mm remote control case [Jaycar HB5610]
1 double-sided PCB coded 15005201, 63.5 x 86mm
4 4G x 6mm self-tapping screws
Extra parts for Altronics version
1 68 x 130 x 25mm remote control case [Altronics H0342 (grey) or H0343 (black)]
1 double-sided PCB coded 15005202, 58.5 x 86mm
4 4G x 9mm self-tapping screws
4 5mm long untapped spacers (or M3 tapped spacers drilled out to 3mm)
Australia’s electronics magazine
July 2020 81
LED2, IRR1 and pushbutton switch S9
mount on the underside of the PCB.
For LED2, bend the leads up by 90°,
6mm, from the lens base, making sure
that the anode lead is to the left. The
LED then mounts horizontally with
the centre of the lens 4mm below the
bottom of the PCB board. LED1 is also
mounted horizontally but 3.5mm below the PCB, with its leads bent some
4mm back from the LED base, again
ensuring that the anode is to the left.
IRR1 should also be mounted with
the centre of its lens 4mm below the
bottom of PCB. Insert its leads from
the top and then bend them down by
90° so that the body swings beneath
the PCB. A cutout is provided for its
leads to pass to the other side of the
PCB without sticking out. The back
of the lens should be in line with the
front edge of the PCB.
More common parts
Switches S1-S8 are mounted orientated as shown, with the flat side to the
bottom edge of the PCB. We used four
white-topped and four black-topped
switches, although any colour or colour combination can be used.
For the Jaycar case, the battery snap
is inserted from the battery compartment side first, with the leads passed
through to the PCB. For both versions,
the leads from the battery snap pass
through wire stress relief holes that
are on the PCB.
First feed the wires through the
outside 3mm hole, then under the
PCB and up through the next 3mm
hole. Then solder the ends directly to
the plus (red wire) and minus (black
wire) pads.
cleared by pressing any of the S1-S8
switches. If cleared, LED2 will just
flash momentarily.
Finishing the case
Drill out the end panel for the LEDs,
IR receiver and switch. A drill guide
is available and is provided with the
front panel label that’s included with
of the front panel artwork. This can
be downloaded from the SILICON CHIP
website (www.siliconchip.com.au).
For the Altronics case, it is essential
to place the drilling template onto the
end panel with the correct orientation
before drilling.
The top panel of each case can then
be drilled out for the eight switches using the drilling template that’s a part
of the front panel label artwork. Again,
make sure the top panel is orientated
correctly before drilling.
Drill a small hole first and gradually enlarge the holes with a reamer. As
you enlarge the holes, regularly check
that each hole is located correctly and
is not too large by placing the panel
over the assembled PCB and switches.
Countersinking the inside of the holes
can help locate the switches better as
the panel is brought up to meet the
switches.
The front panel artwork includes
Testing
Apply power and check that there is
4.75-5.25V between pins 20 and 1 of
IC1’s socket. If that is correct, disconnect power and insert IC1. Check that
LED2 lights when the Mode switch
(S9) is pressed.
Press the Mode switch again so that
LED2 goes off. Then press one of S1S8. The LED should light up. Stop the
playback of whatever random data
was in the memory chip by pressing
any of S1-S8.
Next, clear the memory by pressing the Mode switch (LED2 will light)
and holding this switch closed for 10
seconds until the LED flashes to indicate that all memory has been cleared.
You can test if the memory has been
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rectangular blank labelling borders for
each switch. This can be written onto
using the ‘fill and sign’ option on a PDF
reader before printing. Alternatively,
use a fine-point permanent marker on
the label itself to indicate what each
switch is programmed for. More space
is provided for switches S2, S4, S6 and
S8 than for S1, S3, S5 and S7.
A front panel label can be made using overhead projector film, with the
label printed as a mirror image so the
ink will be between the enclosure and
film when affixed. Use projector film
that is suitable for your printer (either
inkjet or laser) and affix using neutralcure silicone sealant.
For black cases, use a light-coloured
silicone. Light-coloured cases can use
clear silicone, such as the roof and
gutter type. Squeegee out the lumps
and air bubbles before the silicone
cures. Once cured, cut holes in the
film for the switches with a hobby or
craft knife.
Other labels and for more detail on
making labels, see www.siliconchip.
com.au/Help/FrontPanels
Mounting the PCB
The PCB attaches to the base of the
Jaycar case using four self-tapping
screws into the integral mounting
bushes.
The PCB for the Altronics case is
mounted on the lid section using 5mm
spacers and 9mm self-tapping screws.
If the spacers are M3 tapped, they will
need to be drilled out with a 3mm drill
to allow the self-tapping screws to enter freely. Finally, attach the lid to the
case using the four screws supplied
with the case.
Programming it
Orientate the Remote Control As-
The assembled PCB inside
the case. Note how some of
the components must be tilted
to allow the case to close.
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Looking at the top
of the Jaycar case
version – it’s
simply a matter
of “point-n-shoot”
– press the button
for the previously
programmed
action required.
sistant with the front end of the case
with the LEDs and IR1 facing you and
placed near the audiovisual items you
are using.
To record the IR sequences required,
place the Assistant in record mode by
pressing the “Mode” switch using a
small probe such as a ballpoint pen.
The indicator LED lights, and you then
press the button you wish to record a
sequence for. The indicator LED flashes in acknowledgement.
The IR Remote Control Assistant is
then ready to record a series of infrared codes from one or more infrared
remote controls. Ensure that these are
aimed at the infrared receiver on the
Assistant as you press each button to
broadcast the required codes.
Recording does not start until a remote control signal is received. That
way, on playback, the code sequence
begins straight away. Any pushbutton (S1-S8) can be pressed to end the
recording. Further sequences can be
stored by pressing the Mode switch
again and a using a different pushbutton switch (S1-S8) for each new
recording.
At the start of recording, the memory
allocated for that pushbutton switch
is cleared, ready for a fresh recording.
That means that the new recording
overwrites any previous recording for
that pushbutton switch.
Note that when the IR Remote Control Assistant is first placed in the record mode, record mode will end after ten seconds if one of the S1-S8
switches are not pressed within that
time. Similarly, after record mode is
initiated and a switch is pressed, it
will abort if an infrared code is not
received within ten seconds.
If you want to clear the memory
for one switch without making a new
recording, press and hold the mode
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you want to clear. The memory is first
cleared, and then the IR Remote Control Assistant waits for the receipt of an
infrared code. Press any switch to end
the recording. The memory will stay
cleared since no IR code was received.
Hints and tips
switch and then press and hold the
switch for the memory to be cleared
and hold both for ten seconds. The acknowledge LED will initially flash out
the pushbutton number (from 1 to 8)
before clearing the memory associated
with that switch.
Another method of clearing an individual memory is to press and release
the Mode switch and then press the
switch associated with the memory
You can record just about any infrared code sequence, but be aware that
sequences could get out of synchronisation if you are not careful.
For example, if you program the unit
to change from one source to another,
the source you select might depend on
what source was selected originally.
Also, if one of the receivers misses
a code during playback, the following codes could have no effect or the
wrong effect.
So you will need to position the
transmitter LED in a location where
all the receivers will pick it up reliably before playing back a complex
sequence, and avoid moving the unit
too much during playback or blocking
the IR signals.
SC
Quick instructions
Modes
There are three modes: Playback, Record and Erase. Playback is the default mode, and
the unit is normally in this mode. Record mode is invoked when the Mode switch
is pressed and released, after which the indicator LED (LED2) lights. It will automatically return to Playback mode unless a recording is started within 10 seconds.
Bulk erase
Full erasure is performed by pressing and holding the Mode switch alone for 10 seconds.
Individual sequence erase
Press and hold in the Mode switch (S9), then while holding that, press and hold in the
pushbutton switch (S1-S8) required for memory erasure. Keep pressing both pushbuttons for 10s until the indicator LED (LED2) flashes out the switch number. Release the switches; the selected sequence has been cleared. LED should now only
flash momentarily when that pushbutton is pressed.
Recording a sequence
Place the Infrared Remote Control Assistant near the audiovisual equipment with the
front end facing toward you. Press the Mode switch (S9) and release. The indicator
LED will light. Press the pushbutton (S1-S8) required for the recording. The indicator will flash off and then on again.
Point the audiovisual remote control(s) toward the audiovisual equipment, making sure
it also faces the infrared receiver on the Assistant. Start the sequence by pressing a
remote control button for the operation first required within ten seconds. Continue
to run through the sequence using the remote control to perform the tasks. The indicator will flash at the infrared encoding rate.
Press any pushbutton (S1-S8) to end the recording.
Sequence playback
Playback mode is the default mode, and in this mode, the indicator LED is off. Point the Infrared Remote Control Assistant toward the audiovisual equipment, then press the required
switch (S1-S8). The recorded sequence will be reproduced via the onboard infrared LED.
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July 2020 83
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