From eb4901edc41737f50ab4ac078505b423f34a487d Mon Sep 17 00:00:00 2001 From: Wolfgang Hallmann Date: Sat, 21 Oct 2023 18:46:03 +0200 Subject: [PATCH] Fly with solar panels. What to know --- README.md | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 4 deletions(-) diff --git a/README.md b/README.md index 50a60ac..24225b0 100644 --- a/README.md +++ b/README.md @@ -255,13 +255,67 @@ Payload 3: ### Using two alternating frequencies in HORUS-V2 Mode -In Europe there are two areas of RX stations they listen on their regional frequencies. So the problem may occur that you have to decide -wich channel you have to choose for best reception reports on the track. So the idea was to define an additional channel to transmit. -You will find in the config.h the entry `RADIO_SI4032_TX_FREQUENCY2_HORUS_V2_ACTIV` on default `false`. -To activate this, set it to `true` and use define `RADIO_SI4032_TX_FREQUENCY2_HORUS_V2` to add a second frequency e.g. `437600000`. +In Europe, there are two areas where the receivers listen on their respective regional frequencies. So the problem can arise that you have to decide +which channel to choose for the best reception reports on the route. So the idea was to define an additional channel for sending. +You can find these two new entries in config.h + +``` +#define RADIO_SI4032_TX_FREQUENCY2_HORUS_V2_ACTIV false +#define RADIO_SI4032_TX_FREQUENCY2_HORUS_V2 437600000 +``` +To activate this, set it to `true` and add a second frequency. + From now on, the frequency will change after each TX Intervall in HORUS-V2 Mode (not working on HORUS-V2-continous-mode). +### Flying solar powered + +#### Rebooting after not reaching a 3D fix + +Sometimes you launch the sonde in an area where GPS cannot be received and then take it to where GPS is available. +In such cases, it has been found that there is simply no GPS FIX, no matter how long they wait. Then you try a RESTART. +Most of the time it works then quite fast. This is not a problem if you are still on the ground. + +There are ideas to prepare a RS41 powered by solar panels only. Goal is to fly more then one day don't have this limit with batteries. +Some addional enhancements are needable to reach this goal. One of them is to make sure after sunrise that there is a GPS fix. +To solve this its a good idea to make a System Reset in the air if a missing GPS-FIX reaches out some time limit (e.g. 3 minutes or longer). + +The `config.h` shows new entries to activate this improvement. + +``` +// Enable this setting to make a cold start on the CPU if GPS-Fix missing longer then GPS_REBOOT_MISSING_GPS_FIX_SECONDS +#define GPS_REBOOT_MISSING_GPS_FIX_ENABLE true + +// If enabled above, define threschold how long a missing GPS-Fix before cold start (dont hold it to short) +#define GPS_REBOOT_MISSING_GPS_FIX_SECONDS 200 +``` + +#### Probe does not start at sunrise because current too low + +If solar panels are to be used, it is important to consider a few things: + +- Autostart nessesery. Currently, it is still unclear when the RS41ng software will cause a probe to start on its own when batteries are connected. +If the batteries are inserted into the existing holder (2 x AA type) the voltage is conducted via a voltage regulator on the board. In this case, +the button on the board probably works and must be pressed to start the software. This is not helpfull if you wait for pushing a button in the air. +But there is another method to connect the battery voltage. In this case, the regulator is bypassed. Here the probe starts immediately as soon as at +least 1.5 volts are present (up to 4 volts are tested). The battery is connected directly to one end of an SMD component. +I'm sure your community has more info on this. +- Solar panels should deliver 3-4 volts and a current of 200 mA. +- You need a capacity of around 2.000 µF to buffer the solar power a little bit. Somehow the RS41 will not start without them. + +Lets have look on the voltage if the sun rises: +- Its dark, the capacitors are empty. +- First sun on the panels brings the voltage up to 300 mV. This will load slowly the capacitors. +- After a while the voltage comes up to 500 mV. The LEDs on the board start to glow and flicker a bit. +- More and more sun falling on the panels. The voltage climbs to 800-1.000 mV. Over 800 mV the red LED shows that the software starts but... +- While the voltage is still to low on 800 mV the main procedure on the board tries to init some hardware elements. This is successful +up to the moment when the GPS module gets initialized. There is a loop programmed and waiting the gps_init will work one day. Not this time. +- The voltage climbs still in background but the loop will never end. The only way to init the GPS unit successful is to initiate a System Reset. +- A System Restart is now implemented after waiting 10 times the loop initiated the GPS unit unsuccessfull. +- If the System is booting meanwhile the voltage is up to get the GPS unit initiated this time. +- Everything fine now .... But there is no guarantee this way of recovering is the best one - in practice it works. + + ## Building the firmware