There it is. Marcy-1's first free flight on the golf course.The 900Mhz RC transmitter interferes with the telemetry receiver even though they're on opposite ends of 915Mhz. You need to keep them separated or on different bands, which requires rebuilding the entire transmitter.The notoriously fickle capture compare on the PIC is still extremely hard to get working in the field.
Salute the Mar.
By now, we realized she had a serious roll oscillation which is probably from not having enough weight on the balace beam.
Last flight, ending in a tree impact.
Marcy-1, warrior copter.THE 900MHZ NIGHTMARE
Tracked down the SI4421 problem to a floating solder joint. The SI4421is electrically identical to the MRF49XA.
Dual 900Mhz receivers for Vika 1 & Marcy 1.
Ancient 72Mhz converter from 3 years ago.
900Mhz converter fits inside the case.
900Mhz converter has resistors for all the inputs to prevent overloading.The 900Mhz conversion runs at 9600bps. Manual control now has the full60Hz of the RC transmitter. It was reduced to 50Hz when it was 72Mhz.
After being plagued by broken wires & floating solder joints, the Marcy1 ground station was finally capable of flight.
Vika 1 is also beginning a long hard 900Mhz upgrade. Since the MRF49XAhas only a 16 bit buffer being consumed at 86000bps, getting VikaCopter to output data fast enough requires buffering an entire packet on the flight computer & sending it in 1 shot instead of sending data as it's collected.MICROMAG3 RIDES AGAINSince we didn't win the free $parkfun hibache knife set & no-one knowsif Marcy-1 will work, that leaves digging the old Micromag3 out of thegadget graveyard & fabricating a new Marcy-1 flight computerspecifically for it.A 3rd revision will be necessary. Depending on traffic, these boardscan be fabricated in 1 commute & since we're tax paying renters, thechips are fully recycled.
Spent $30 to find out only Mane Clog Remover, only at Walmart works.Other drain cleaners have additives which prevent the NaOH fromdissolving photoresist. Mind you, you're supposed to use batchpcb.
Etching skills are a bit rusty after the draino experiments.
Size comparison. Went back to single sided boards because they'relighter with our methods.
This one has a simple dipole with choke inductors, no decouplingcapacitors, 1 digital line under the chip & it still works. Filling aground patch & using 3 decoupling capacitors is only necessary formaximum range.
Suspect any inductors above 8nH would do the job but these were whatthe balun had.
Marcy 1 phase 2 with magnetometer grafted on.
& this is the raw & derivative of the magnetometer output at flight RPM. Flight RPM has 144 samples per period. The limiting factor is radio bandwidth, not the magnetometer. It takes 20000bps of radio bandwidth to downlink that. Monocopters take the zero crossings of the derivative to get azimuth & angular rate, but it's not so easy in realtime.