Serin serout problem

[skimask]

my father cuts meat and has a cold room in the garage, This unit is wireless receiver that will give him the temperature. It is not crucial if there is a downtime to charge the battery, (or a downtime of a few hours if the compressot breaks down) but at least a warning that they are running low.

The transmitter is in the room and it's wireless/battery powered? And the receiver is elsewhere, plugged into the wall or something?

Ya know for that matter, you could (and probably are but I'm not sure), transmit the transmitter's battery voltage along with temperature data to the receiver.

[lerameur]

nope, the transmitter is in the garage, pluged into the wall, there is a 40 feet line runnin gfrom the sending module to the sensor, becasue the sensor is inside the fridge. This part is done, I installed the module up high inthe garage with the antenna sticking out, it is a straight line to the house. The receiving module is wireless, so he cantake it in his room or the kitchen etc..

[skimask]

nope, the transmitter is in the garage, pluged into the wall, there is a 40 feet line runnin gfrom the sending module to the sensor, becasue the sensor is inside the fridge. This part is done, I installed the module up high inthe garage with the antenna sticking out, it is a straight line to the house. The receiving module is wireless, so he cantake it in his room or the kitchen etc..

Ok, TX, powered, garage....

RX - portable, battery powered. Couple of notes I thought of. If the receiver doesn't get a good update for a minute or something, a light/alarm or something goes off as an indication to check on the transmitter (power went off or the transmitter got kicked over by the cat or something out there).

Have you already tried the TX module with this 40ft of wire? Does it work?

[lerameur]

yes the TX module is fully completed , I was doing my earlier test with it.
well also, i wanted to add a led for the battery alarm. A led for when the temperature goes over 50 F, and a piezo buzzer that gos off for 10 sec if the temperature goes over 50 F.

[skimask]

yes the TX module is fully completed , I was doing my earlier test with it.
well also, i wanted to add a led for the battery alarm. A led for when the temperature goes over 50 F, and a piezo buzzer that gos off for 10 sec if the temperature goes over 50 F.

So what's the next step?

[lerameur]

I am using a pic16F88 and I amnot sure whcih pins to use. Right now I am using pins 1, 2, 17, 18 for my lcd out and also pin 6,7 for control. Pin 5 and 14 for powering. Pin 8 for input.
If I use the Vref, then i need to move my lcd out pins to pin 10 through 13 ( I wanted to us these for led out, piezo and other outputs i needed. I never had luck outputting on port A. Shouln't be hard to get it going.
Also I dont have any MCP1525, I only have 7805 chips maybe use this chip for now and replace it when I get another ?...
and use a voltage divider on the 7805 to obtain 2.5 v ?
I assume the MCP1525 is an LDO chip ??

also instead of using 40k and 10 K resistors, can I use 400k and 100K ? would that take up even less power ?

[lerameur]

hi , maybe i woul dneed expert advise here on wiring and soldering. I think I did an ok job, but when i move my wires a few times after soldering, they break, I use the same wire that i use on the breadboard (picture you seen )
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[skimask]

I am using a pic16F88 and I amnot sure whcih pins to use. Right now I am using pins 1, 2, 17, 18 for my lcd out and also pin 6,7 for control. Pin 5 and 14 for powering. Pin 8 for input.
If I use the Vref, then i need to move my lcd out pins to pin 10 through 13 ( I wanted to us these for led out, piezo and other outputs i needed. I never had luck outputting on port A. Shouln't be hard to get it going.
Also I dont have any MCP1525, I only have 7805 chips maybe use this chip for now and replace it when I get another ?...
and use a voltage divider on the 7805 to obtain 2.5 v ?
I assume the MCP1525 is an LDO chip ??

also instead of using 40k and 10 K resistors, can I use 400k and 100K ? would that take up even less power ?

Well, if you can't change the Vref pins around, then maybe use 2 A/D converters and compare your fixed reference against the total applied? In other words, if you're battery ever got down to 2.5v, then the A/D input would be at maximum. Just takes a bit of math I supose...

And since you don't have any MCP1525 or anything like it, I know one thing you do have that does have a fixed reference...

Or do you?
I'll give you a little bit to think about it, then I'll give you the answer.

And also since you don't have a fixed voltage (or do you? )...you won't need to worry about the resistors for now.