{"comment":{"url":"https://api.github.com/repos/rhempel/lego-linux-drivers/comments/15360431","html_url":"https://github.com/rhempel/lego-linux-drivers/commit/ef71ed788ee57e18e4954885fc6bd7857549579e#commitcomment-15360431","id":15360431,"user":{"login":"pootle","id":919663,"avatar_url":"https://avatars.githubusercontent.com/u/919663?v=3","gravatar_id":"","url":"https://api.github.com/users/pootle","html_url":"https://github.com/pootle","followers_url":"https://api.github.com/users/pootle/followers","following_url":"https://api.github.com/users/pootle/following{/other_user}","gists_url":"https://api.github.com/users/pootle/gists{/gist_id}","starred_url":"https://api.github.com/users/pootle/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pootle/subscriptions","organizations_url":"https://api.github.com/users/pootle/orgs","repos_url":"https://api.github.com/users/pootle/repos","events_url":"https://api.github.com/users/pootle/events{/privacy}","received_events_url":"https://api.github.com/users/pootle/received_events","type":"User","site_admin":false},"position":null,"line":null,"path":"","commit_id":"ef71ed788ee57e18e4954885fc6bd7857549579e","created_at":"2016-01-10T16:32:25Z","updated_at":"2016-01-10T16:32:25Z","body":"I like this. In fact I like this a lot!\r\n\r\nOnly 1 comment at the moment from first reading is on syncing. I really like this idea, but I think the -100 to +100 control range is too coarse. a 0.5% error in a matched pair can easily build up to a very noticeable / inconvenient problem. For example a tracked vehicle or vehicle with 2 independently driven wheels 10cm apart with 3cm diameter driving wheels could be over 5 degrees adrift after travelling 1 meter (near enough the same for a yard) - 1 wheel will be approx 1cm adrift from the other). This is a very visible offset!\r\n\r\nGiven the tacho tick is 1 degree, the best we could achieve with the hardware is 0.26mm or 1/100\" over a distance of 1m. This is 40 times more accurate. \r\n\r\nI would suggest going for the largest number you can handle in 16 bits without being in danger of overflow and hopefully at least 10,000.\r\n\r\nbtw in your search for a PC master / slave, how about reference / client\r\n\r\nThe same would apply for any situation syncing multiple axis joints - each turn the client can drift by almost 2 degrees."}}