Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

EMI Interference

Status
Not open for further replies.

dirtbiker1824

New Member
Hi I am making a RF controlled Relay for controlling my light switches in my house. I have the RF side of my board down but I'm having trouble with the power supply. I purchased the BP5034D5 power module from Rhom. Here is the datasheet link https://www.rohm.com/products/databook/pm/pdf/bp5034d5.pdf. I have the power module connected as shown in the application circuit and I'm getting a 5volt output. I am having trouble however with my decoder circuit (433 Mhz) when its powered by the AC power module. For some reason when I have the power module powering the circuit my RF decoder behaves differently than when I connect it to a steady 5VDC power source. I believe that EMI could be causing issues but it seems strange since the problem is not erratic. Normally when I push a button on the transmitter side I have it set up so that the pin is latched on the decoder side. But when I have the AC power module powering the circuit the decoder acts like its in momentary mode, the pin only stays low as long as I hold the button down on the transmitter, once released it goes high.

Do you think this is a problem with Electromagnetic Interference and if so what can I do to shield or fix this.

Thanks you very much for all help! This problem has been killing me lately as I am not very familiar with EMF or AC power.

**I know the thread title is repetitive, sorry but I can't change it**
 
Last edited:
What sort of capacitor filtering do you have on the 5 volt input to the circuit as it sounds like ripple in the input voltage resetting the circuit to me.
try placing something like a 1000uf cap across the 5v and ground rails on the power input to the circuit, you might also need a small cap across the rails to like a 0.1uf cap for the smaller transients.

Do you have decoupling caps close to your ic's as well, its a good practice to have them.

Pete.
 
I just have a 100uF Electrolytic capacitor as my filter capacitor. I assumed this would be enough since the Vp-p according to the datasheet is .05 V which doesn't seem like much to me since the operating range of the decoder is 2.2V - 5.6V. I will try with the 1000uf tho. Also what do you mean decoupling caps near the IC. I know almost nothing about filter circuits so any/all help you could offer would be greatly appreciated!
 
You might check the decoder to make sure you have everthing that should be tied up tied up and not floating.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top