input & output circuits
Embedded Files
BACKGROUND
BACKGROUND
this week we make two PCP INPUT and OUTPUT circuit, as the two PCP have a multi-function to put all that we learn about mux, the opamp, shift register and apply it to show how this work.it was really good week in the lamb .it was my first time to work with mux , opamp and shift register and this makes me excited to see what is the final output of my PCP .
INPUT circuit
INPUT circuit
OUTPUT circuit
OUTPUT circuit
rationale behind the design of the input and output boards
rationale behind the design of the input and output boards
Thermistors are solid-state devices with a variable resistive portion whose resistance varies with temperature; they are also known as thermally sensitive resistors. These devices are usually made from semiconductor-based metal oxides with sintered or metallized leads in a two-terminal ceramic bead, glass-encapsulated device, or disc configuration. Resistance reading errors in the presence of moisture are removed when hermetically sealed.
If we send a constant current through the thermistor and then measure the voltage drop across it, we will be able to determine its resistance at a particular temperature. But how do we add a constant current power
If we send a constant current through the thermistor and then measure the voltage drop across it, we will be able to determine its resistance at a particular temperature. But how do we add a constant current power
supply?
supply?
Analog Devices/Linear Technology has a really nice solution using a thermistor network T1 as a sensor in one leg of the bridge configuration. An UA741 excites the bridge. This design has a response that is linearly related to the temperature sensed by the thermistor.
we also need some more inputs like switches to use it to trigger the output value so that we used 4 channel dip switch to minimize the number output pins we also used 74151 8 input multiplexer to explode out the input pins and make it connect to one output pin
as mux can be used as a data selector so we will be able to take the reading from the thermistor and the switch then using mux we can select wich input we will take.
after that we programming our controller to take the value then opreating a certain process to the output board which contain an rgb led and shift register.
shift register loads the data present on its inputs and then moves or “shifts” it to its output once every clock cycle, hence the name Shift Register.
A shift register basically consists of several single bit “D-Type Data Latches”, one for each data bit, either a logic “0” or a “1”, connected together in a serial type daisy-chain arrangement so that the output from one data latch becomes the input of the next latch and so on.
INPUT PCP design using Eagle
INPUT PCP design using Eagle
input circuit components
74151 (8 Input Multiplexer)
trimmer pot 1kohm
Thermistor NTC 10kohm
6.2kohm resistor
10kohm resistor
4-ch DIP switch
UA741 op-amp
1X40 0.1'' pin header
OPAMP and thermistor Sch:
OPAMP and thermistor Sch:
from the library importing the opamp which will work as a comparator
importing a thermistor for sensing the temperature as it gives different resistance value due to surrounding temperature
importing a potentiometer to adjust the value of the TEMP to compare it by the OPAMP
make a NET and connect it as shown
MUX AND DIP SWITCH Sch:
MUX AND DIP SWITCH Sch:
adding a multiplexer to use it with multi inputs and get one output pin
importing dip switch to use as an input for the mux
pin header
pin header
using a 5*1'' pin header for power and the MUX pins
clearnce DRC
clearnce DRC
distance DRC
distance DRC
SIZE DRC
SIZE DRC
PCP routing
PCP routing
Garber viewer
Garber viewer
using Garber viewer for exporting pdf to use it in GIMP then exporting a png for MODS
using Garber viewer for exporting pdf to use it in GIMP then exporting a png for MODS
using Garber viewer for exporting pdf to use it in GIMP then exporting a png for MODS
using Garber viewer for exporting pdf to use it in GIMP then exporting a png for MODS
bottom and profile in Garber viewer
bottom and profile in Garber viewer
drills and profile in Garber viewer
drills and profile in Garber viewer
GIMP editor
GIMP editor
using GIMP editor for importing the Png files which is the supported extension for the MOD
tracies png
tracies png
drills png
drills png
profile png
profile png
NOTE: do not forget to flip the PNG as you work in the bottom layer
INPUT CIRCUIT FABRICATION AND SOLDERING
INPUT CIRCUIT FABRICATION AND SOLDERING
INPUT CIRCUIT AFTER SOLDERING
OUTPUT PCP design using Eagle
OUTPUT PCP design using Eagle
output circuit components4
74595 shift register
IRF530 "N-Channel MOSFET
5mm RGB LED
High power SMD warm LED
2-pin screw terminal 5mm
10kohm resistor
330 ohm resistor
1x5 pin header 0.1''
SHIFT REGISTER
SHIFT REGISTER
LOGIC MOSFET
LOGIC MOSFET
TO CONTROL THE HIGH POWER LED
HIGH POWER LED
HIGH POWER LED
high power led with 2 screw terminal for powering with external power source
high power led with 2 screw terminal for powering with external power source
RGB LED
RGB LED
REGISTER PINOUT
REGISTER PINOUT
pin header connected to the pinout of the shift register
Distance DRC
Distance DRC
clearance DRC
clearance DRC
SIZE DRC
SIZE DRC
PCP ROUTING
PCP ROUTING
Garber viewer
Garber viewer
tracies and profile
tracies and profile
drills and profile
drills and profile
GIMP editor
GIMP editor
traces png
traces png
drills png
drills png
profile png
profile png
OUTPUT CIRCUIT FABRICATION AND SOLDERING
OUTPUT CIRCUIT FABRICATION AND SOLDERING
coding and testing
coding and testing
finally, I programmed my ATmega board as shown in the images
to take the reading from the dip switch and thermistor as I make the selector pin of the mux to be triggered for each pin for 5 sec after that the next pin will be selected using the truth table of the mux
each pin will triggered the the controller chip will take the reading after that it will operating a certain process
1-i the first switch is high the rgb led will blinking red light then green
2- if the second switch is high the rgb led will blinking red light then green then blue and vise versa
3- if the third switch is high the rgb led will blinking red light then green then blue and turn off the blinking again
4- if the fourth switch is high the rgb led will blinking will flashing colour after one
5- i the thermistor detect a higher temperature then which i adjust the opamp will give a high value and then the rgb will flashing with red led colour
all input is low so the rgb is going to be off
all input is low so the rgb is going to be off
all the input is high so the RGB is going to blink color after one
all the input is high so the RGB is going to blink color after one
peoblems
peoblems
What I learned this week is...
there was a short circuit in the input board which prevents the thermistor and OPAMP from working well
there was a fault in the design of the output circuit as i forget to put a pullup resistance for the RGB LED so i solder it as jumbers
the high power led was broken down so i didn't soldering it in the OUTPUT BOARD
CONCLUSION
CONCLUSION
What I learned this week is...
how to use an opamp as comparator
using the multiplexer to expands input pins
what is the shift register how to use it
using the thermistor to measure the temperature value
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