[Swlug] Remote SWLUG on Jitsi tonight Tuesday 17 May 2022 at 7pm BST

[Rhys Sage]

It was great to see you all at the conference. I hope I didn't hog the call too much. The sound quality was a little hard at times but overall the technology seems to work reasonably well.

The drone I'm thinking about initially will run off some 18650 cells. I bought 8 with a marked capacity of 5600mah and if you know 18650 cells then you'll know that's nonsense. They're a Chinese brand called SkyHawkEye and are actually about 2300mah which is on a part with most other 18650s. With no BMS circuitry in them they're half the weight of normal 18650s which is why I like them.

The plan with the drone as I've mentioned is a delta wing with a V tail so basiclally a delta V. That keeps construction simple and adds other advantages. So far for the drone I have...
Servoes (two should be fine) a motor and motor controller, a BMP280 pressure sensor, a GPS unit, several Pi Picos but I will use only one for the drone and an accellerometer. I did go nuts and but some HATs but while they will fit my Pi 3B+ (which I use as a desktop in my bus/motorhome), they don't fit well with the Picos. In terms of availability I can only get Picos with any ease. I'd love to get a backup 3B+ but they're unavailable. 

The GPS sensor should provide lattitude, longtitude, altitude, local time, direction and speed. I have one with a USB connector that does. As the Pico does not have a USB connector I had to buy a different one. I hope it uses IC2 (which I'm only just learning about) as I believe the BMP280 and accellerometer both do. That will make conncetivity way easier.

The plan for navigation is to keep the drone at a constant 80-120 feet above the ground in level flight. To that end I might have to experiment with LIDAR or install some form of SONAR. I feel SONAR is more likely to be successful than LIDAR at that range. An interesting thing to add would be RADAR for collision avoidance. I'm getting way ahead of myself though. The first step will be to get the Pico to produce information from all the devices individually before I try anything fancy.

As far as the radio distress beacon I was discussing, that's going to be a very simple device. I'm getting a lot of hostility over that from online radio ham groups. They seem to think very highly of their licences and get very snooty about discussing anything with anybody that does not have a ham license. Thus, testing might be challenging. I want to work on two things. I can produce Morse code as a light flashing and as a buzzer buzzing though it worked far better when I ran the buzzer via a transistor and a 1K resistor straing from the Pico 3.3v pin. Running it from pin 15 to the buzzer to GND seems a bit hit and miss. Eventually I will omit the buzzer and have it running a relay to operate a Michigen Mighty Might radio transmitter. I was going to build that today but noticed the conferance was on. 

Eventually the plan with the radio beacon is to have it going two way using a Pixie QRP with an e-ink or LCD B/W display that displays incoming morse code as text. I did see a nifty little keyboard the size of a pack of fags on Magpi a few days ago. That might be an interesting addition. Then powering it I was thinking of small solar panels that charge a capacitor, allowing the user to enter text which is then sent automatically every 5 minutes. Receiving should use far less power and might run straight off some 6v solar panels. 

How I miss social interaction like this. I just don't get much in SC. I go from home to work, to the dump or the shops. I don't even get to the rifle range more than once every couple of years. You made my day today. Thanks.

Rhys Sage