Robin Lovelock
Senior Member
Hi Folks. Things are progressing well with the small picaxe-controlled robot boat, which I hope will be launched this year from UK to USA. It's still doing 24/7 testing, sailing around Bray Lake, and I'm now looking at the software, testing it with my GPS simulator, and checking the logic to navigate from UK, past the Azores, the Bahamas, Bermuda and to a spot to be decided in the USA 
All explained on www.gpss.co.uk/autop.htm including video showing our recent sea trial on the UK south coast.
This thread relates to sound output from my picaxe - the little servo driver board. It's been working well, taking GPS data in RS232, wind direction sensor as analogue voltage in, and driving the rudder servo, to steer the boat around waypoints. The software also uses the TUNE command to play tones into a little loudspeaker that is near an FM transmitter - so we receive information on the shore, no more than 100 or 200 yards away. This is only for testing on Bray Lake - but it's just possible we might use it at sea.
I thought I'd posted a thread on this sound stuff, but I couldn't find it. I was probably interested in text to speech.
Now I'm thinking of dedicating another picaxe to sound, driving the loudspeaker, and using whatever is simplest to pass data from one to the other.
e.g. my autopilot picaxe might pass a code to say which sound or tune to play from the "sound picaxe".
There are some side effects which I've lived with: e.g. our tunes and subroutines to play tones, use up valuable memory. We can just about squeeze our new waypoints to the USA in, but if we put this sound stuff into another picaxe or connected chipset, it would release memory. Perhaps more significantly, playing the tones with TUNE causes a slight twitch of the servo - there is obviously interferrence here.
Here is what we use the sound for:
1) range to the next waypoint as tones: e.g. dah-dah-dit = 50+50+10 = 110 metres.
2) inside a waypoint box - we play theme from "Close Encounters"
3) starting a new tack at 45 degrees to the wind "Popeye the Sailorman"
4) rudder left - low tone "dah"
5) rudder right - higher tone "dit-dah"
Our autopilot picaxe software has a feedback loop lasting about 6 seconds:
1) use SERIN to read data from the GPS including lat/lon, direction, speed.
2) read direction from wind direction sensor and convert to absolute direction.
3) test if lat/lon in a waypoint box, or other values, and change the destination lat/lon if needed.
4) calculate the target heading from GPS lat/lon to the destination lat/lon.
5) modify this target heading if it means sailing too close to the wind.
6) calculate the error in heading between target heading and real GPS heading.
7) move the rudder servo to steer the boat.
go back to step 1 above.
Sounds are generated in several of these stages, using TUNE (via subroutine calls).
Any ideas on a simple way of connecting two picaxe, such as my servo controller, and communicating.
I can then put the sound stuff onto the second picaxe. It will only take a few milliamps - power drain is important.
Or - maybe there is a text-to-speech solution ?
Many Thanks in advance for any ideas.
Robin
www.gpss.co.uk/autop.htm
All explained on www.gpss.co.uk/autop.htm including video showing our recent sea trial on the UK south coast.
This thread relates to sound output from my picaxe - the little servo driver board. It's been working well, taking GPS data in RS232, wind direction sensor as analogue voltage in, and driving the rudder servo, to steer the boat around waypoints. The software also uses the TUNE command to play tones into a little loudspeaker that is near an FM transmitter - so we receive information on the shore, no more than 100 or 200 yards away. This is only for testing on Bray Lake - but it's just possible we might use it at sea.
I thought I'd posted a thread on this sound stuff, but I couldn't find it. I was probably interested in text to speech.
Now I'm thinking of dedicating another picaxe to sound, driving the loudspeaker, and using whatever is simplest to pass data from one to the other.
e.g. my autopilot picaxe might pass a code to say which sound or tune to play from the "sound picaxe".
There are some side effects which I've lived with: e.g. our tunes and subroutines to play tones, use up valuable memory. We can just about squeeze our new waypoints to the USA in, but if we put this sound stuff into another picaxe or connected chipset, it would release memory. Perhaps more significantly, playing the tones with TUNE causes a slight twitch of the servo - there is obviously interferrence here.
Here is what we use the sound for:
1) range to the next waypoint as tones: e.g. dah-dah-dit = 50+50+10 = 110 metres.
2) inside a waypoint box - we play theme from "Close Encounters"
3) starting a new tack at 45 degrees to the wind "Popeye the Sailorman"
4) rudder left - low tone "dah"
5) rudder right - higher tone "dit-dah"
Our autopilot picaxe software has a feedback loop lasting about 6 seconds:
1) use SERIN to read data from the GPS including lat/lon, direction, speed.
2) read direction from wind direction sensor and convert to absolute direction.
3) test if lat/lon in a waypoint box, or other values, and change the destination lat/lon if needed.
4) calculate the target heading from GPS lat/lon to the destination lat/lon.
5) modify this target heading if it means sailing too close to the wind.
6) calculate the error in heading between target heading and real GPS heading.
7) move the rudder servo to steer the boat.
go back to step 1 above.
Sounds are generated in several of these stages, using TUNE (via subroutine calls).
Any ideas on a simple way of connecting two picaxe, such as my servo controller, and communicating.
I can then put the sound stuff onto the second picaxe. It will only take a few milliamps - power drain is important.
Or - maybe there is a text-to-speech solution ?
Many Thanks in advance for any ideas.
Robin
www.gpss.co.uk/autop.htm
