Radio novice Umar “2E0UMR” Munir has constructed a Bluetooth knowledge modem for varied digital modes, utilizing low-cost off-the-shelf parts managed by an Arduino-compatible microcontroller — with plans afoot to show the Blue Dmod right into a single-PCB implementation.
“On [the] market there are many choices for sound card-based knowledge modems, like Signalink, Digirig, and many DIY and low-cost modems,” Munir explains of his inspiration for the mission. “I have never seen any Bluetooth primarily based audio knowledge modem aside from Mobilinkd which is sadly Bluetooth serial port TNC [Terminal Node Controller]. With a purpose to preserve the price to minimal I obtained collectively parts I already had, [I] simply needed to order the microcontroller as I did not have any small type issue microcontrollers.”
The Blue Dmod delivers Bluetooth knowledge modem for digital modes on a good finances. (📷: 2E0UMR)
The Blue Dmod is constructed round an affordable BT002 Bluetooth audio module, with Munir connecting the radio’s microphone enter to the module’s left audio channel, the radio’s audio output to the module’s microphone enter, and the module’s proper audio channel to an Arduino-compatible microcontroller. There is a relay for push-to-talk (PTT) performance, as “not all radios like transistor/MOSFET-based PTT,” Munir explains.
“To maintain [it] all easy I used [an] RJ45 port to attach [the] radio to [the] modem,” Munir writes. “It [is] simple to make RJ45-based cables [rather] than utilizing any particular connector. I’ve examined the ‘Blue Dmod’ with Wouxun KG-UV9D, Wouxun KG-UV9K, and TCA/PRC 152 [radios]. On TCA/PRC 152 I had so as to add a ferrite core on excessive energy.”
Extra data on the mission is on the market on Munir’s web site; an preliminary schematic and the mission’s supply code can be found on GitHub underneath the reciprocal GNU Common Public License 3.