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Temperature and light sensor with signalling LEDs
Rebuilding an existing module module to be a stand-alone unit, with temperature sensor and signalling LEDs. Uses an AVR ATmega8 microcontroller.
I/O
Inputs
- PC0 Temperature sensor (analog)
- PC1 Light sensor (analog)
- PC2 Analog input 3
- PC3 Analog input 4
- PC4 Analog input 5
- PC5 Analog input 6
Calculations
- Temperature

- Light intensity

Outputs
- PB0 Buzzer
- PB1 Green LED (PWM)
- PB2 Yellow LED (PWM)
- PB3 Red LED (PWM)
- PD3 Life signal
- PD4 Link activity
Serial communication
D-sub 25-pin
- 13.8V
- 0V
- 5V out (from internal voltage regulator)
- 0V out
- Analog input 3
- Analog input 4
- Analog input 5
- Analog input 6
Communication
Interfacing is done with RS-232, using MAX232 or MAX202.
Serial settings
- Baud
- 38400
- Data bits
- 8
- Parity
- None
- Stop bits
- 1
Source code
Gallery
Schematic drawing
Parts used
Qty.
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Part
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1 × |
AVR ATmega8-16PU, DIL-28, 16 MHz, 23 I/Os
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1 × |
Buzzer, electromagnetic PCB, 12V, 35mA, Ø16mm, int. oscillator
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5 × |
Capacitor, aluminium electrolytic, 1 µF, 50V
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2 × |
Capacitor, aluminium electrolytic, 10 µF, 25V
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3 × |
Capacitor, aluminium electrolytic, 47 µF, 25V
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1 × |
Capacitor, ceramic, 1 nF, 100V
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3 × |
Capacitor, metallized polyester foil, 10 nF, (0.01 µF)
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1 × |
D-sub soldering cups, 25 pin male
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1 × |
D-sub soldering cups, 9 pin female
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1 × |
DIL socket, 16-pin, 7.62mm
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1 × |
DIL socket, 28-pin, 7.62mm
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1 × |
Enclosure, plastic (1591 FL), 150x80x50mm, flange
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1 × |
Fuse 5x20 mm, 800 mA, fast-acting
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1 × |
Fuse holder, panel, 5x20mm, PTF30
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1 × |
Heatsink, 27.3K/W, 19mm, attachable, TO220
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1 × |
LED 5mm clear, Green, 2.1V, 20mA, 385mcd, 6°
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1 × |
LED 5mm clear, Green, 3.4V, 20mA, 10.000mcd, 25°
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1 × |
LED 5mm clear, Red, 2.1V, 20mA, 7.000mcd, 20°
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1 × |
LED 5mm clear, Yellow, 2.0V, 20mA, 250mcd, 6°
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1 × |
LED 5mm clear, Yellow, 2.1V, 20mA, 10.000mcd, 20°
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1 × |
LED lens 5mm, CLB 300 low, Green
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1 × |
LED lens 5mm, CLB 300 low, Yellow
|
1 × |
LED lens 5mm, CLF 280, Green
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1 × |
LED lens 5mm, CLF 280, Red
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1 × |
LED lens 5mm, CLF 280, Yellow
|
1 × |
Light-to-voltage sensor, TSL 252R, 9.4mV / (μW/cm2)
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64 cm2 |
PCB, stripboard, 100x160mm, 160cm2
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1 × |
Power jack, panel, 2.1mm, plastic housing
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1 × |
Resistor, carbon film, 0.25W, 100 Ω, 5%
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2 × |
Resistor, carbon film, 0.25W, 150 Ω, 5%
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2 × |
Resistor, carbon film, 0.25W, 330 Ω, 5%
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2 × |
Resistor, carbon film, 0.25W, 4.7 kΩ, 5%
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1 × |
RS232 interface, MAX232CPE, dual
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1 × |
Spacer, round unthreaded, 3mm, Ø6mm, Delrin
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35 × |
Straight pin header, female, Single row, 2.54mm
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2 × |
Straight pin header, male, Dual row, 2.54mm
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40 × |
Straight pin header, male, Single row, 2.54mm
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1 × |
Temperature sensor LM35DZ, 0 to +100 °C, +-0,6 °C
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1 × |
Transistor, NPN, 100 mA, 45V, 0.5W, BC547B
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1 × |
Voltage regulator +5V, 2 A, L78S05CV
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