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ideas:temp_management

RFM69HW Temp Management

Idea 1: Crystal Oven

Components

  • RFM69HW
  • Moteino or another micro
  • 2 Resistors (10ohms)
  • Mosfet

Design

  • 2 resistors in parallel lying over the RFM69HW crystal acting as heaters
  • Mosfet is used to connect the resistors to ground (they are connected to VCC as well) to complete the circuit and heat up the crystal.
  • To control the temperature we use PWM to turn the mosfet on and off, the hotter we want the more often we turn the mosfet on.
  • The control system uses a PID loop

Current Implementation

  • Using the PID v1 library on the arduino (using a moteino)
  • Measuring temperature with the onboard RFM69HW temperature sensor
  • Working well using a setpoint of 20C to test.

Possible Improvements

  • Improve heating efficiency with better insulation
  • Tighten the PID loop
  • Use an external temperature sensor which maybe more accurate

Idea 2: Adjust Freq to Temp

Experiments

This section is more for documentation.

Temperature Drift

  • 04/01/15 23:04 - AB → AH6,
    • AH6 reporting T-6
    • AB reporting T25

  • In this screenshot its possible to appreciate the difference between the frequencies of the nodes, currently AB is only rx'ing 20% of AH6's beacons most likely due to the frequency difference.
  • 05/01/15 07:34 - AB → AH6
    • AB = T24
    • AH6 = T1

  • Comparing the 2 pictures
    • 1st image frequency difference was 27 pixels
    • 2nd image was 21 pixels

ideas/temp_management.txt · Last modified: 2015/01/06 22:18 by jcoxon