I am a new member who has just signed up.
Long story short, I have been working with Picaxe chips for about 15 years and have solved a handful of little project problems with them over that time. However, last month my ENTIRE electronics toolkit was lost in the post, tools, components and all, so I found myself in the strange position of starting, literally, from scratch.
Since I was starting from scratch, I figured it was a good time to ask around and see if maybe there was something more suited to my needs than the picaxe, particularly as I have three pretty urgent projects on the go (which is why my stuff ended up in the post, I was travelling around with it and left it behind on an interstate visit.).
One of the suggestions that was made to me was the M5Stack system, and I have to say, at first glance it looks absolutely perfect for my needs.
All three of my projects require a simple display, some buttons to control settings and the ability to switch on or off a few circuits. And of course, that is all built in with the M5Stack. Perfect!
One project requires interfacing with a handful of temperature probes and yes, I've read the article on interfacing more than 3 DS18B20 probes which answered all my questions there. Tick! (I only need four)
One project required interfacing with an opto-isolated hall-effect current sensor, and I really cannot see any problems there. Tick!
But one project requires interfacing with a GPS and a compass. Now, I've found the commonly used GPS module (M8N) that is in the M5Stack format and it looks perfect. The external GPS antenna is a real bonus, and the whole integration looks straight forward and suited to my needs.
However I cannot decide if the built in MPU9250 in the M5Stack Gray kit will be suited to my needs.
I am building an autopilot for my boat. I already have the steering motor (actually I already have the whole autopilot, but the brains of the thing are going potty) so all I need to do is control the motor with a simple reversible 12 volt DC circuit, which I had done successfully with some big MOSFETS using the picaxe. (Yes, they were lost in the post too.)
The code logic is very simple and the processing power required is minuscule. But I cannot figure out if the onboard MPU9250 will work as a compass given that:
1). It is inside the case and might therefore be affected by power flow in the unit itself.
2.) Whether it is actually an ok compass in itself. I don't need more than two or three degrees accuracy, but if it drifts more than that, it will affect how long I take to get from A to B.
Can anyone shed some light on the compass and how it actually behaves in the real world?
For the record, it won't be a show stopper if it is no good, as I can buy plenty of cheap and simple I2C compass chips that are ok, but I like the idea of using the inbuilt version if I can.