I am hoping to get some advice on a little project I want to build. I have very little electronics experience, but I learn quickly. I want to build a device that senses the ambient temperature in my son's room, and then either turn on an IR LED if the temperature is below a certain temp, leave it OFF if within an acceptable temp range, and BLINK the IR LED if above a certain temp. I want the acceptable temp range to be about 20C-22.78C.
For a temperature sensor, I was thinking of using the TMP37, because it outputs at 20mV per degree, which would give me finer tuning over the more common TMP35 and 36, which outputs at 10MV per degree.
I am trying to decide between creating a circuit using an XOR gate and 2 PUTs to direct the flow to either an ON circuit, or a blinking circuit based on the temperature output...OR using an Arduino to program an ATtiny and simply connect the temperature sensor and IR LED to that and program it to do the same thing.
I need to know which of these options will be cheapest and use the least power. I already have an Arduino. I also want it to be as small as possible, so using small batteries will be necessary. I was thinking of using either a couple button batteries (2032), or maybe 2 AAs (Alk or Rechargeable). A cheap, rechargeable Lithium camera battery might also do well. I just don't want to be changing batteries every month. So I guess I am planning on supplying 3-3.3V.
I know about sleep mode on the ATTiny, and I am hoping I can have it sleep for 5 minutes, wake up and take some temp readings and find the average, then hopefully if within the acceptable range, go back to sleep. If outside the range, it will either blink the light, or turn it on steady, and then check again in another 5 minutes. If the temp is outside, and it turns the LED ON, will it be able to go back to sleep, or will that turn the LED OFF? If it will prevent sleeping, I could throttle it down to a low power mode.
Thank you for any suggestions you may have! I am excited to learn more!
For a temperature sensor, I was thinking of using the TMP37, because it outputs at 20mV per degree, which would give me finer tuning over the more common TMP35 and 36, which outputs at 10MV per degree.
I am trying to decide between creating a circuit using an XOR gate and 2 PUTs to direct the flow to either an ON circuit, or a blinking circuit based on the temperature output...OR using an Arduino to program an ATtiny and simply connect the temperature sensor and IR LED to that and program it to do the same thing.
I need to know which of these options will be cheapest and use the least power. I already have an Arduino. I also want it to be as small as possible, so using small batteries will be necessary. I was thinking of using either a couple button batteries (2032), or maybe 2 AAs (Alk or Rechargeable). A cheap, rechargeable Lithium camera battery might also do well. I just don't want to be changing batteries every month. So I guess I am planning on supplying 3-3.3V.
I know about sleep mode on the ATTiny, and I am hoping I can have it sleep for 5 minutes, wake up and take some temp readings and find the average, then hopefully if within the acceptable range, go back to sleep. If outside the range, it will either blink the light, or turn it on steady, and then check again in another 5 minutes. If the temp is outside, and it turns the LED ON, will it be able to go back to sleep, or will that turn the LED OFF? If it will prevent sleeping, I could throttle it down to a low power mode.
Thank you for any suggestions you may have! I am excited to learn more!