Thread: RF remote VFD control

I was playing around with some simple/budget RF remote switching gear from Itead (Radio Frequency) and it dawned on me that this stuff could easily be used for RF control of something like a VFD.

So I mocked up a prototype as follows.

VFDRC.jpg

A is an Arduino Mega 2560 micro controller - I used this as the Mega has 6 "interrupts" (and at least one interrupt is required for each button on the remote marked "RC")

The US$4.50 RC communicates with a US$2.50 RF receiver module (marked RFM on photon) the curly black bit of wire is the antenna.
Pairing between the RC and RFM is quick and easy.

The RFM is connected to a suitably programmed Arduino board via any 4 of its interrupt ports.
Once the Arduino has a knowledge of the status of A/B/C/D buttons then pretty much anything can be done with that information.

On my prototype circuit, pressing Button A on the RC switches relay "R" on and off - photo shows LCD display as being ON with LED on relay also on. the relay says it's is good for 240V/10A but I would trust it to handle that continuously but its more than enough to switch a VFD "ON/OFF" via the low voltage switching circuits on a VFD.

This could also be used to turn on a big DC if the small relay was to drive a secondary "beefier" relay.
Not that big a deal so far.

In my prototype the B/C/D buttons are used to change the VFD's output frequency ie motor speed.
"B" toggles between "frequency increments" of "1" and "5" Hz. Display show "DF:5"
Repeated pressing of "C" or "D" respectively increase or decrease the frequency by the frequency increment"

The required frequency will be converted to a scaled Voltage (0-5V) using one of the Arduino's Analog output ports and then amplified by a factor 2 using a basic Op Amp and then sent to the VFD analog input frequency control (it needs 1-10V input). Haven't tested this yet but should work OK.

Haven't fully tested the range of the RC but it was still working at over 12m when I ran out of testing room.