Hello,
I'm currently experiencing an issue with a circuit which should be very simple, but is behaving strangely. What I am trying to build is the attached schematic. Basically, I'm trying to switch a load on/off using an RF receiver module. The load in this case is basically just a resistor of 2 ohm (e-cigarette vaporizer for a miniature fog machine).
Expected behavior:
When the button on a remote is pressed, the DATA pin on the RF module will go high. This will open the channel on the MOSFET and turn on the load. When the button is released, the DATA pin goes low and the load is switched off.
Actual Behavior:
The load will turn on/off with a frequency of approximately 4-5 Hz.
Where it gets weird:
If i disconnect the DATA pin and drive the MOSFET Gate directly with a bridge to VCC, the load turns on and stays on as expected. While the load is on, the DATA pin on the RF module is always 0 (measured with a multimeter). I.e. even though in this configuration the DATA pin is not connected to anything, and the only connections of the RF Module are the VCC and GND connections, it ceases to work.
What I've tested:
- Measured the voltage between RF Module VCC and GND with/without the load on. Without load it was 4.1V, with load it dropped to 4V. I tested the RF Module in isolation at 3.7V and it works without problems
- Disconnected the load. In this case the RF Module seems to be able to switch the MOSFET without problems. At least, the voltage at DATA behaves as expected
- Used a different load (DC Motor). The same issue occurs
- Used a different MOSFET (IRLB8721). The same issue occurs
- Used a different LIPO without short protection
- Added a 220uF cap between VCC and GND at the RF Module
At this point I'm running out of ideas what the problem might be. Maybe something causes noise on VCC which I cannot see with the multimeter or something interferes with the 315 Mhz RF signals? I might get access to an oscilloscope this evening, so I can at least look at VCC voltage with/without load on.
Any help would be greatly appreciated.
The components are:
Simple RF M4 Receiver:
https://www.adafruit.com/product/1096IRLB3034 MOSFET:
https://www.infineon.com/dgdl/irlb3034pbf.pdf?fileId=5546d462533600a40153566027b22585Power Source 2000mAh 3.7V Lipo:
https://www.adafruit.com/product/2011