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Electric heater and timer controller
This module was part of the rack box project — which was terminated when I moved out of my first apartment.
Controlling the electric heater, and give alarm if server stops responding. Uses an AVR AT90S2313 microcontroller.
- The module turns off the heat in the living room after the porch door has been open for 20 seconds. 90 seconds after the door has been closed the heat is turned back on. It can also be controlled using an external switch.
- A short signal pulse from another module or a switch, will activate the output for 15 minutes. Used for turning on the test voltage on the Rack status panel. A new pulse within these 15 minutes turns the output off.
The solid state relay leaks a small amount of current to the oven, about 10mA. This current can be eliminated using a resistor in parallel over the oven supply after the relay. A 22K, 5W resistor should be the job.
- Porch door, from Multi-purpose module 1
- Manual oven disengage
- Signal activate
- Oven relay N.O
- Oven relay N.C
- Oven LED
- Oven local LED
- Signal output
- Lifesignal (to Module stability monitoring unit 2)
- Red: 5v
- Black: 0v
- Input: Porch door
- Input: Manual oven disengage
- Input: Signal activate
- Output: Oven relay N.O
- Output: Oven relay N.C
- Output: Oven LED
- Output: Signal
- Output: Lifesignal
|1 ×||AVR AT90S2313-10PI, DIL-20, 10 MHz, 15 I/Os|
|1 ×||Capacitor, aluminium electrolytic, 10 µF, 25V|
|2 ×||Capacitor, ceramic, 22 pF, 100V|
|1 ×||Capacitor, ceramic, 1 nF, 100V|
|1 ×||D-sub soldering cups, 9 pin male|
|1 ×||DIL socket, 20-pin, 7.62mm|
|3 ×||Diode, small signal, 1N4148/Ph|
|1 ×||Enclosure, plastic (1591), 100x50x25mm|
|1 ×||LED 5mm coloured clear, Green, 2.1V, 20mA, 30mcd, 10°|
|1 ×||LED 5mm coloured clear, Red, 2.1V, 20mA, 8mcd, 10°|
|2 ×||LED holder 5mm, RTC51, black plastic|
|2 ×||Mounting bracket, DIN rail, Plastic|
|1 ×||Quartz crystal oscillator, 4 MHz|
|5 ×||Resistor, carbon film, 0.25W, 330 Ω, 5%|
|6 ×||Resistor, carbon film, 0.25W, 4.7 kΩ, 5%|
|3 ×||Resistor, carbon film, 0.25W, 10 kΩ, 5%|
|1 ×||Switch, toggle, 1-pole, micro, on-on|
|5 ×||Transistor, NPN, 100 mA, 45V, 0.5W, BC547B|