RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

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odranch
 
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RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by odranch »

Hello - My recently purchased T4 and Keyfob are not working, as far as I can tell. I have tried multiple 5v sources and get no response D0-D3 pins. VT does goes high on button press. There is 5v on the SC2272-T4 Vcc. There are voltage swings on DIN but I did not go as far as to attach a scope. The Keyfob blinks on press. I plan to use this transmitter/reciever on a Circuit Playground Express. Please Help.
Thanks.

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mikeysklar
 
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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by mikeysklar »

Can you post a photo of your hookup and link to the code you are test?

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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by odranch »

Hello - Since my post I have found that the receiver works, after a fashion in my application, and does bring D3 and D2 ( I’m using an Adafruit 2 button key fob) to a high or low state BUT ONLY IF I AM TOUCHING THE ANTENNA. This state change turns the CPX LEDs on and off simulating a flame. I have tried this with the antenna coiled and uncoiled. I can view the state of digital input A1 via the serial monitor and can verify that it does change state. The CPX is inside a Dietz kerosene lantern ( glass globe/metal frame) and I have tried mounting the receiver both inside and outside the lantern but get the same results. The system works great on the bench but fails in my real world application. The system is powered by a 5v supply when not connected to the USB. Any ideas on the strange antenna/receiver behavior?
Thanks.

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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by odranch »

This appears to be a useless spam reply by LEAHDAN and not constructive.

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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by mikeysklar »

deleted the spam post.

What part of the lantern did you mount the CPX in? I could see using the upper area where the glass meets metal blocking the antenna signal.

The CPX is a 3v3 controller I would think that feeding a 5v signal into it from the RF T4 would be an issue unless you are doing a form of level shifting.

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odranch
 
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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by odranch »

Hello - The 315 MHz receiver is powered by a 3.3v pad on the CPX board and not a separate supply though this is below the 5v specified for the receiver. Could I use Vout since this is a slightly higher voltage? I am not using a level shifting circuit.
In addition I am also trying to use the cap touch pads on the CPX. When connected to USB on the bench they work great. On battery (3.7v, 750 mAh lipo) they fail to operate at the touch settings that were used when the program was downloaded. My sensors are copper small copper foil plates attached to the sensor pad with 6” wire.
Thanks

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Re: RF T4 315Mhz / Keyfob '2' 315 Mhz not working for CPX

Post by mikeysklar »

Using the Vout to power the RF T4 is not a good idea without level shifting to protect your GPIOs on the CPX. The SAMD21 is only designed for +0.3v tolerance over nominal 3.3v. With level shifting it would be fine to use Vout to power the RF T4. It will also be able to supply more current.

The captouch situation you are seeing is strange. Works on USB and not on battery. Can you start a new thread for that issue so we can stay one topic at a time.

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