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electronics exam

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illillillill

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Hey, i have somewhat of a retarted teacher and i just got my project today, and found that he hadn't taught us half of teh stuff wer' asked to produce. i'm not bad at alectronics, the jerk just didn't teach us right so i'm persuing information on my own.

here's what i'm asked to build in 5 weeks:
- a program (i can do that myself pretty easily)
- an interface print with driver + relay + 7segment display + buttons (never even seen a 7segment display before)
- a temperature stabilised cabinet containing a heat sensor and a heater (the sensor will tell the relay through a program when there is heat enough and the heater will stop heating)
- finally i am to write a report on it all, (i can do that all by myself)

so basically what i need soem help with is the print which should contain everything for the PSU, the analog read function, the 7segment displays, and the relay control for the heater,

the controller i will be using is an ATMEGA328P-PU

i've spent a year so far on this education and i'm not gonna throw it away because of a jerk, so i'm begging you people. if someone can come up with a really good solution for me i might even consider donating to show my gratitude.
 

crutschow

Well-Known Member
Most Helpful Member
Is the display supposed to display the temperature? Are the buttons to control the temperature setting?

Need more info.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
You've seen a seven segment display before. A wrist watch, a timer on a microwave and a DVM.

I remember that, or similar assignment. The displays and buttons were provided for us and no temperature control.

If you have to multiplex the digits in software and input numbers it gets more difficult. That's what we had to do. You can always cheat and use "UP" and "DOWN" buttons. Use the "decimal" point to indicate heating and no 0.1 degrees.

At a minimum you will need PI or Proportional/Integral control otherwise you'll get an overshoot.

I did a weird project at work for an environmental chamber. I used the proportional range and changed that to (+-100%) and used it to control the temperature of a surface thermometer rather than the air temp of the chamber. Kinda fun.
 

illillillill

New Member
hehe yea i realize i should post some more info, the keypad . a 4x4 with digits , and probably a-d letters and * 0 # in at the bottom, is supposed to send information into an ATMEGA328P-PU which will contain a program that should send the numbers out to the display units so you can chose a temperature, view current temperature, possibly add a hustory too so you can see temperature 1 hour back or something, but what i really need help with is to figure out which keypad to use and how to make it communicate with the display unit, how much voltage i should have on the output of the PSU powering the keypad and the display units, on the same print is also a small relay that will act as a switch for the heating unit. :)
 
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