I'm thinking that using an old battery-powered drill used as the=20 motor and gear-box might be an inexpensive and reliable=20 solution. Many of these drills are simply discarded because it's=20 often cheaper to purchase a new drill with new batteries than to=20 purchase replacement batteries. Certainly, I see excellent drills=20 other than missing or defective batteries available for a few dollars=20 at garage sales and flea markets. Drive the drill motor with a ramped PWM source. I would arrange a slip mechanism on the arm itself and mount your=20 limit switches to the arm rather than to the motor assembly. dwayne PS - you could arrange to have a mode where the motor speeds up very=20 quickly, then stops and reverses even more quickly. This would allow=20 you to slap the offending motorcycle operator repeatedly until they=20 get the message. dwayne At 04:04 PM 1/9/2015, David C Brown wrote: >This is a barrier to stop passing motorists using my drive as a passing >place (because I have just had it relaid and don't want it wrecked by heav= y >traffic like the old one). > >The barrier is not meant to be a physical barrier, rather a psychological >one. Even if the barrier is quite flimsy very few drivers are bloody >minded enough ignore it. (It will be well illuminated). > >The family will have a remote control to operate it. I think a period of >10 seconds is the mist they will want to wait so the motor has to come up >to speed and move through ninety degrees in that time. Obviously startup >time and running speed are interrelated. > >Since I envisage a small motor and a lightweigh barrier I see no safety >problems but I will fit stall protection. > >Environment is outside in a Derbyshire winter (often wet, rarely very >cold) and I have devised a pretty good scheme for keeping water out. --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .