Back in the now distant memory which is the summer I ordered a CTR2-MIDI from Lynn at Lynovation.

Background from their website:

If you already use a radio controller app like Marcus Roskosch’s (DL8MRE) apps for iOS and MacOS, Remote Ham Radio to operate contest quality remote radios, Thetis for your Apache ANAN or Hermes-Lite 2, or SDR-Console on Windows, CTR2-MIDI will provide an 8 function tuning knob, 6 programmable function buttons, and a multi-purpose paddle input jack. It’s small, only 60mm x 60mm x 20mm (2-3/8″ square and 7/8″ high) not counting the knob. This unit supports USB and Bluetooth-LE MIDI and is specifically designed with hams in mind.

On my desk, I use an Icom RC-28 to control my FlexRadio with the excellent SmartSDR from Marcus Roskosch. I was looking for a similar controller for use on my iPad (also using SmartSDR). The availablity of a port for a key/paddle was also very interesting to me as you’ll note from this post.

As I suspected when the CTR2-MIDI arrived from the US, it was a great, high quality solution. The only quibble was that I needed to grab a power bank or cable to attach it to the iPad to power it (in my use case, the data connection is performed via Bluetooth LE). I completely understand why a battery was not built into the CTR2-MIDI, something which Lynn has confirmed would have increased the size and expense of the unit.

As you may have noticed, I’m on a bit of a 3D printing/designing spree at the moment so I sat down to design an extension to the CTR2-MIDI. Lynn was very responsive to my emails and mentioned the board does have a LIPO charge controller which could be directly connected to a 3.7v battery. However, this connection is on the underside of the board. I wanted this to be a reversable and non-destructive addon, not a modification.

My search for a solution didn’t take too long as Seeed Studio, who make the ESP32-S3 board used in the CTR2-MIDI also produce the Lipo Rider Plus board which will provide a suitable 5v output from a 3.7v LiPo battery, as well as allow the battery to be charged. I purchased one and mocked up a proof of concept.

Alt

Fast forward a few weeks, more than a few test prints (which will be recycled) and I now have a nice compact non-destructive addon using a 1400mAh battery which will power the device for a at least 10 hours.

As an added bonus Lynn has confirmed this is also compatible with the CTR2-Micro.

Alt

I have uploaded the files to Printables under the CC BY-NC-SA 4.0 licence soon for anyone who wants to adapt for print their own for non-commerical purposes.

If you would prefer to purchase a working unit complete with the board, battery, switch and cabling enclosed in a high quality PLA print, then please check out shop.g7ufo.radio or drop me an email.