GM0ONX's Radio Artisans Arduino Rotator Controller
My ZL1BPU rotator controller served me well for many years, but it was not without its problems. The controller did not have an integrated digital display and
relied on a voltmeter circuit to display the heading which did not always align the computer display. The Yaesu emulation was poor being unidirectional and
ZL1BPU own commands only supported by PSTrotator.
I came across this project on Goody K3NG's Radio Artisans website and though this would make an excellent alternative way to do things. Clone Arduino
Uno boards are available on eBay for less than a fiver with the 20 by 4 line costing about the same. The project 'sketch' is well documented which is a
good thing because they are a few elephant traps in it for the uninitiated and I must have found them all.
The only other non standard thing compared to K3NG's original is in my controller the relays are the are active low, that is they close when the circuit is
grounded and were purchased from eBay complete with the PCB circuit in place. These are very handy little unit s and a steal at less that £3 for the set.
The project is completed with 99p encoder switch also from eBay. You can find my version of the sketch which is set up for 'ground to operate' relay boards,
20*4 display by clicking here. You will need one of the older Arduino IDE to load this sketch and you can find them here . I believe I used version 1.0.5.
Remember you will have to calibrate the rotator this is done via the Arduino IDE program and is very simple. Rotate the rotator fully CWW and then from
the command line send the letter '0' then return. Send the rotator fully CW and then send the letter 'F' and then return. The interface is compliant with the
most common Yaesu GS232 commands and you can find more info on this on page 16 of the GS232B Manual found here.
The Ham IV rotator however has a major Achilles Heel in its design, it shares the return path with the rotator motor and brake which has a 0.5V ripple
voltage on it causing 'interference' on the rotator position sense voltage. I originally modified the variable resistor in the Ham IV so that the wiper was
isolated from earth and ran a separate to the wiper arm, but after a few weeks the isolation wore through and made connection with earth again.
Following a conversation with Barry Beggs GM3YEH he suggested that I build a filter to remove the ripple voltage and this worked very well. Because the
wiper arm is connected to earth I had to provide a separate power supply just for the sense voltage in which neither the positive or negative lines are
connected to earth.
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Now in its third guise the GM0ONX Ham IV controller |
Plenty of space left for a speed controller board for slow starts and stops if required. |