Nick Mulder

Hi, A project we are working on at the moment requires us the ability to have control of an operate switch on a remote piece of moving gear. Because the sight lines are so unreliable we cant use IR ... Does any one know of a radio control cct or kit that gives us one or more bits of info (parallel) over at least a 10m range, if not more ... Is this easy ? or more to the point >> small and lightweight ? cheers, nick mulder

they were used in Nintendo power gloves ...

the reason i am aware of PID control is through reading up on motor control - perhaps you could look into modifying some of the cct's and systems used in that field ? the forums at CNCzone.com have heaps of info on that... [move] :P

wouldn't proportional control be enough ? or are you introducing drag/delay/error in the system yourself ? An outline of the sensor and driven system would be helpful for anyone who wishes to help you, are you working in analog or going digital ? a lamp and LDR/phototransistor ? what are the surrounding conditions/is it isolated ?

Hi, I am working on a project that is using LDR's to sensor light which needs to be scaled to both 0-5v and 0-12volts with adjustable 'zero' points and scale factors depending on the ambient light mins and max's - looks like I need a similar cct... I have only worked with op amps making simple comparators so far so this is new to me - after reading up on them I now know how to make a non-inverting amplifier with an adjustable scale factor - what I need to know is how to get the zero point ... If I put 12 through my LDR and instead of getting a nice ~0-12volts output (from darkest dark to full on sunlight) and instead got say an 4-8volt range I would need to scale the output by 3 - easy.. but how do I make the 4volts output as zero before thnis scale ? also I believe that op amps can be made to convert log scales to linear - I think this would be of use as I need a linear output compared to the LDR any suggestions ? is it a simple switch of the resistors in what has been discussed here already ? cheers as always, Nick

Hi, I am keen to make the circuit outlined here: http://www.aaroncake.net/circuits/slave.htm it calls for a '2N5777 NPN Darlington Phototransistor' of which I am yet to find a supply of here in NZ - upon looking at the symbol used for the Darlington Phototransistor in the cct diagram in the link above it seems to be two transistors cascaded together one being a Phototransistor and the other a normal transistor... I dont know much about transistors and especially darlington types but if they are simply a bundled package of two transistors could i make a substitute from the discrete versions ? I ask this as I have a simple NPN Phototransistor here already and a PNP and NPN from other projects I could use.. is it as simple as that ? :P

Hi, I am trying to make a servo driving unit for time-lapse photography on an old 60's 16mm camera 8) - the servo will simply push a mechanical button but it needs adjustability that other systems wont give (like cam-follower DC motor or solenoid) - I have so far managed to get the mechanics all fine but only about 1/2 of the electronics - The servo needs to go from 0 degrees to 180 degrees with a regular frequency spanning from the fastest being the time it takes for the servo to make this movement ~ 1-2 sec (you couldn't go any faster would make the servo not reach its full angle) up to about 60 mins - however if this is unfeasible I'll settle for less ... I can make the pulses that tell the servo to go to these angles with 555/556 timers (haven't done it yet but have found plenty of tutorials online) - I would have two, one outputting a ~ 0.6ms pulse and the other a 2.4ms pulse @ around 50hz . I would have a flip-flop relay switching output to the servo between the two... However, not only do I need to be able to adjust the timing of the switching between these two 555/556 circuits I also need to be able to adjust the duty-cycle of this timing (so I can open the shutter for longer periods for night photography in case your interested) ... So heres the issue, how do I drive this timing flip-flop ?? I considered another 556 circuit doing exactly the same thing as the servo drivers but with a much larger time scale e.g.. 0.000278 Hz (60 mins period) - but this would result in very large RC constants ... is there another way ? (also, as the system driving the switching between the two PWM generators is actually doing the same thing as the two PWM generators themselves but over different time scales could I also use your potential suggestions to also run the servo's themselves ?) cheers, hope this makes sense, Nick [email protected] PS. Sorry, should also add i am a bit of a beginner with practical electronics - I only learned about PWM and this stuff yesterday trolling the net ... :P