Thanks for all the help so far, its quite interesting reading and I'm very keep to try this out.
BILL what would you use instead of the 1n914's? which would you recommend the LZ35DZ or the DS18S20 temp sensors?
No I've not done any programming at all "yet" however hopefully I will soon.
would a development board be worth buying to "experiment" with?
I've been looking for a good one at a decent price and stumbled on this
https://www.mikroe.com/en/tools/easypic5/
anyone have any experience with this or anything similar?
I've still got to decide what programmer to get yet. IF I got that EasyPIC5 board would I need to buy a seperate programmer or would it program the PIC from the computer?
ANY thoughts on using 3 or 4 DS18S20 temperature sensors instead of the LM35DZ's?
Anyone any ideas how (IF) i can get an output to trigger at a set temperature and stay even if the temperature goes higher than the temp I want it to trigger at?
Temp sensors either LM35dz OR DS18S20 depending on which is easier to incorporate and get working
This may sound a stupid question to most of you, but is there a comparator in the pic's that can be used to compare 2 (temp inputs) and trigger different output pins and logic circuitry (AND OR gates etc) for example
(this is what I've got in my mind so far)
INPUT A0 (temp sensor) (set for 75ºC)
INPUT A1 (temp sensor) (set for 50ºC)
INPUT A2 (temp sensor) the LCD Display shows this actual temperature AND shows the word OUTSIDE TEMP (actual temp) ºC (LINE 3 of display)
INPUT A3 (temp sensor) the LCD Display shows this actual temperature AND shows the word INSIDE TEMP (actual temp) ºC (LINE 3 of display)
INPUT B1 +V (from ignition switch)
INPUT B2 +V (from battery)
INPUT B3 push to make non latching switch
OUTPUT A0 (normally LOW) to relay driver circuitry
OUTPUT A1 (normally LOW) to relay driver circuitry
OUTPUT B3 (normally LOW) Siren/buzzer circuitry
OUTPUT 4
OUTPUT 5
OUTPUT 6
OUTPUT 7
IF input A0 ≥ 75ºC AND input A1 ≤ 50ºC AND input B1 is HIGH OR input A0 ≤ 75ºC AND input A1 ≥ 50ºC AND input B1 is HIGH THEN outputs A0 and A1 and B3 stay LOW
AND the LCD display shows the word DIESEL
IF input A0 ≥ 75ºC AND input A1 ≥ 50ºC AND input B1 is HIGH THEN outputs A0 AND A1 go HIGH driving the circuitry needed afterwards needed to activate a relay on each line output)
AND the LCD display shows the word the word VEG-OIL
( IF I remember my maths equations for MANY years ago then ≥ means equals or greater than and ≥ means equals or less than)
IF input B3 goes high AND INPUTS A0, A1 and B1 are HIGH, THEN output A0 stays HIGH AND output A1 goes LOW AND a timer starts that counts for 65 seconds
AND the LCD display shows the word PURGING
IF TIMER = 0 (65 seconds reached) AND INPUT B1 is LOW THEN outputs A0 and A1 go LOW AND power to LCD module goes LOW
IF TIMER = 0 AND INPUTS A0, A1 and B1 are HIGH, THEN OUTPUTS A0 and A1 GO LOW, and the LCD display shows the words POWER OFF! DIESEL ONLY (on 1 or 2 lines)
IF input B1 goes low BUT INPUT B3 has NOT gone high THEN
outputs 1 and 2 go low (inactive turning OFF both relays) BUT output B3 goes HIGH (sounding a siren/buzzer)
AND a timer starts that counts to 65 seconds
AND the LCD display FLASHES the word WARNING (line 1) and shows the word NOT PURGED (line 2)
WHEN TIMER = 0 (65 seconds reached) THEN outputs A0 and A1 and B3 go LOW THEN power to LCD display module goes LOW
IS it possible to program a PIC controller to do all that? and IF so any ideas what kind of external circuitry I'd need as well?
Can you drive an LCD circuit direct from the same PIC chip, or would it need a seperate controller to do this, and if so how would you interface the two?
sorry lots of questions and I'm showing my ignorance of PIC's and programming, but you cant learn if you don't ask questions.
the 3rd and 4th lines of the LCD display and the extra 2 temp circuits are not needed, it would just be handy if I had a 4 line display instead of a 2 line one, or something like 240x 128 LCD Screen
HOPE I've made that clear enough to understand but the last programming I did was in college and they had only JUST got a computer with 4K of ram (yes 4K not MEG) and a printer attached, they hadn't even got a display of any kind, this was in 1977! how things have changed
Future "mods" (IF I ever get this working) and have the LCD SCREEN instead of the 4 line display would incorporate a fuel level sensor that either shows a bar graph of fuel level with the word FUEL next to it, (or above it if this was a vertical bar graph) and the sensor would be a fuel level sensor which I think the values are 240 - 33Ω