Re: Is there a Raduino replacement with supply voltage, FWD & REF readings ?

John (vk2eta)

On Wed, Sep 11, 2019 at 09:01 AM, Razvan Fatu wrote:
- supply voltage indication
- forward power
- reflected power
Hello Razvan,

I had the same objective of creating a portable rig. The easiest and cheapest option I found was to add a second Arduino (a Mini in my case but can be a Nano, the sketch is the same). They communicate over the I2C bus with the 2nd Arduino a slave on the bus.

The advantage is that you get a lot of extra pins but most importantly a new lot of memory for per-processing the data you collect as the memory gets full pretty quick on the Raduino's Nano as you add features. The 2nd Nano can be set to sleep most of the time, adding limited extra current.

I added a FWD/REV and SWR measurement, a battery voltage indication on the display and a two level low battery alarm (with TX inhibit on the 2nd low level), plus a few other features that I thought were useful for a portable rig (Output power control in SSB, ATU, Android/iPhone style mic/headphone with PTT on/off via the call/hangup button, etc..).

I still use the same display (has some advantages on power consumption and readability in the sun) but I alternate the display between not urgent data (like battery voltage and Step Size+Key selection). On Tx I replace the second line by real-time Forward power and SWR. See attached pictures (no antenna handy, so no actual values, sorry).

This may give you some ideas:

For the SWR bridge I uses Don's (ND6T) design described here:
It is sensitive enough to give you readings from about a watt, so useful across the range. Not as precise as Farhan's solution in the Antuino, but ok for my needs.

The latest drawings and sketches for both the main Arduino and the 2nd one are in the file section at;
They are highly configurable by enabling/disabling the functions you want.

The post describing the functions:
and the latest version:

Please be mindful that these sketches are for V3-V4 boards. For V5, the relay switching function and the 2nd IF frequencies need to be changed.

Hope that helps.

All the best,

73, John (VK2ETA)

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