In a previous post I described how to control the internal tuner module of a common 1.2GHz FPV receiver by a PC. Since this setup was only for general tests I put some more efforts and put an AVR tiny44 in control. On a 4 channel receiver I removed the original micro-controller and replace it by a AVR tiny44, running on internal 8MHz oscillator. The tiny44 takes inputs from the 4 DIP switches and controls the tuner by I2C and the LED. Attached to this post is the source code for the tiny44, written for WinAVR compiler. With this code you have the following functionality: DIP1 DIP2 DIP3 DIP4 Function ON OFF OFF OFF Favorite frequency 1, default 1240MHz OFF ON OFF OFF Favorite frequency 2, default 1280MHz ON ON OFF OFF Favorite frequency 3, default 1276MHz OFF OFF ON short OFF Manual tune, 1MHz up OFF OFF OFF ON short Manual tune, 1MHz down OFF OFF ON long OFF Auto tune, 1MHz up every 100ms OFF OFF OFF ON long Auto tune, 1MHz down every 100ms For DIP3 and DIP4 a long press will be 1 second.
Features You can switch the frequency freely with the RP6D1 6ch dual conversion synthesized receiver. The ‘one button’ function makes it extremely easy to change frequency. Normally a synthesized receiver should be larger than the receivers that use crystals. Corona's technology makes it possible to manufacture a synthesized receiver with light weight construction. Including the antenna and the packaging, it weighs less than 10g.
The frequency set using DIP3 and DIP4 will be stored in EEPROM 5 seconds after last tuning action (DIP switch used). After power cycle this frequency will be the start for new tuning. Frequency range for manual/auto tuning is 850MHz to 2200MHz in 1MHz steps. Wiring is given in the source code, header of main.c.
The UDB (or the ArduPilot, or any digital device) emits digital electromagnetic interference which can cause some receivers to 'glitch' when located near to the UDB. For example, I had a lot of problems with both HiTec receivers (one comes with the EasyStar) and my old Futaba receivers. What was happening was that EMI from the UDB was causing the receivers to emit spurious pulses, which caused trouble with both the failsafe input to MatrixPilot, and with the mode control channel. I finally switched to Castle Creations receivers, and have never had any trouble. On Feb 11, 11:37 pm, William Premerlani wrote: Hi FlorinIt is possible that the Corona receiver does not produce enough voltage for the UDB. Could you post a link to some information about it? Interestingly enough, the UDB can work with low receiver voltage if the supply voltage to the UDB is also low.
That is because the input circuitry of the dsPIC30F4011 is based on ratios. So, lowering the supply voltage lowers the trigger voltages. Many receivers produce a constant peak pulse voltage over a wide range of supply voltages. So, paradoxically, the UDB-receiver interfaces works best with reduced supply voltage. That is why we lowered the design voltage from 5 volts to 4.5 volts. It is possible that the reason your first two flights were ok was that the supply voltage to the UDB was low. Best regardsBill On Fri, Feb 11, 2011 at 1:00 PM, MIG-29 wrote.
I see in the troubleshooting section that it is mentioned: 'Sometimes the board starts ignoring manual controls, or switches back to RTL mode unexpectedly This is a problem with some receivers that output servo signals at slightly low voltages. This causes the UAV Dev Board to not be able to see them. One solution is to change to a receiver that sends out stronger signals. Another option is to lower the voltage at which the UAV Dev Board runs from 5.0V to 4.5V. This makes the low receiver voltages look stronger relative to the UAV Dev Board's voltage. ' Maybe Corona is one of these receivers? However it still doesn't explain why it worked for the first two flights.
On Feb 11, 7:44 pm, Peter Hollands wrote: FlorinI'm going to let other people anser this one. But so everyone does not have to seasrch;, here is a link to Florin's receiver. Pete On Fri, Feb 11, 2011 at 5:06 PM, MIG-29 wrote: Hi thereToday I was testing my flying wing using UAVdevboard V3 and Corona RP8D1 receiver. First two flights were OK.
I was tuning the stabilization parameters. Before the third flight during the pre-flight check I noticed that the UDBboard wouldn't initialize.
It had only the RED led ON while the GREEN led was flashing. The period of flashing was not constant. At the same time the RED led on Corona (which has to be ON all the time- meaning it is locked on frequency) was flashing.
Using JUST corona itself without the UDB proved to be working. Apparently only when connecting Corona RX to UDB, problems occured. I am using a UBEC and 3s Lipoly to power my RC receiver, UDB and servos on the wing. The total current consumption measured on the bench while the servos were heavily used was 1.2 Amperes- this is because I am using standard metal gear servos for the elevons and normal standard servo for the throttle. I changed to a FRESH charged standard RC receiver battery (NiCd)hence eliminating the UBEC and the Lipoly, but the behaviour was the same. The RED led was ON all the time while the GREEN led was flashing.
I changed the Corona receiver with a Hitec RCD receiver. Everything was back to normal. What happened? Is there some sort of incompatibility between Corona RX and UDB? If there is, why did it work for 2 flights (total flight time 50 minutes) and stopped working before the third flight? Thanks!