Archive for June 17th, 2010
You’ve seen bits & pieces of this in the previous weeks and months: now it’s up and running!
Admittedly, this is brassboard hardware; I must now build three final versions for our bikes incorporating all the tweaks & adjustments. But it’s time to write this stuff down so I can find it again … and perhaps you can use some chunks, too.
What it does:
- adapts the mic & earbud in our bicycle helmets to the mic and speaker jacks on an amateur radio VHF-band HT
- provides a handlebar-mounted push-to-talk button
- transmits the AFSK data burst from a TinyTrak3 GPS interface through the audio stream for APRS tracking
- powers the HT and circuitry from an external battery
Why we need it:
- voice intercom for our family rides: we talk without shouting at each other
- safety communication for public service events supported by the local amateur radio club
- GPS-based APRS position reporting for those events
- trip monitoring on our long solo rides
- it’s a neat tech hack with lots of Quality Shop Time
Major sub-projects (some already partially written up):
- somewhat modified TinyTrak3 board
- circuit board combining voice audio + TT3 + PTT + power
- slide-in enclosure replacing standard HT battery pack
- helmet mic and earbud mounting
- external battery pack
- antenna mount (an easier version) for a standard mobile whip antenna
I don’t have an instruction manual to go along with this, nor is there a parts kit available. You’ll certainly want to modify everything for your own purposes; the circuit board and case certainly won’t fit whatever HT you’re using!
Over the next several days, I’ll be describing & documenting the tricky parts… in no particular order, because I’m not going to sort my notes & photos ahead of time.