RF based wireless temperature monitoring system without μcontroller... HELP

[hurikane]

Dear Guys,
i am considering designing a RF based temp. monitoring system. However, i don't have access to μcontrollers and especially the burning kits. I've read extensively on this and i've realized that μcontroller is the best way to go, but i was hoping that someone might have another idea on the implementation with minimal design tradeoff. i live in a part of Africa where i cannot even an audrino or zigbee, so am looking for usefuul links and suggestions on how i can go about with the implementation within the next 4 weeks.
Would be very great if anyone could help...
cheers!

 

[crutschow]

What RF frequency and what distance?

 

[canadaelk]

Also: What temp range and display detail (or just hi/lo warning) E

 

[WTP Pepper]

Sorry you cannot get access to such uP kits as many have on board temp sensors. Combined with low power, they can acccurately measure ambient temp. Many have RF systems built in like the Nordic Semi conductor series. Many UK comps ship worldwide, it does depend on the price you can pay.
Could you design a stable XTAL controlled RF oscillator whose overall drift is temperature dependant?
Maybe a series of window comparators driven from a temp sensor that trigger different caps to be switched into a tuned circuit to pull it. Not ideal, but a start.

 

[picbits]

555 timer with a thermistor tranmitting a frequency proportional to the voltage on a spare radio frequency ? Decode with a frequency to voltage converter then comparators or similar to display the temperature ?

Without a microcontroller though you're creating a lot more work for yourself.

 

[DerStrom8]

A comparator setup would be able to switch something if the temperature goes above a certain limit (or below). It would be very difficult to monitor the temperature without some sort of uC though. A microcontroller would not only make it easier to build the circuit, but it would make it easier for YOU to build it. IMHO the uC is definitely the way to go--much simpler all the way around.

 

[ronsimpson]

This application note is temperature to RF and RF to micro computer.
There is no micro on the temperature end.
There is a micro on the readout end.

I know it is not what you want but it has some good ideas.

You could try a basic stamp where the micro goes. They are programed from the PC with just a serial port.

 

[hurikane]

something above 50m and i was thinking of a 433MHz

 

[hurikane]

Also: What temp range and display detail (or just hi/lo warning) E

i intend to use a 7 segment together with a buzzer and/or LED to indicate a warning when the temp exceeds certain value. I have already purchased a LM35 sensor so i suspect the temp range will be between -55 to 150 deg cent.

 

[hurikane]

thanks guys for your helpful contributions...
even i f i have a μC now i don't have the kits to burn the program. Is there anyway i can get a tailored μC of this sort.
thanks ronsimpson for the link...
I'm ready to work hard, a flow chart of the design stages will be very helpful.
thnx in advance.

 

[ronsimpson]

If you don't want a micro;
The temperature censor in the link above has a output that is a frequency related to temperature. Room temp is 273hz. Frequency=1hz/Kelvin C=K-273

If you build a frequency counter that counts for 1 second you will read out in Kelvin.
If you could build a counter that starts out at -273 and counts up it will read in C.