I was looking for a very simple mechanical device that does 3 simple operations:
1) move up 5cm
2) move up 5cm (for a total of 10cm)
3) move down 10 cm (to the starting position)
Dimensions: big enough to suspend a 50x50 mm2 specimen (so a pretty small device)
This device has to be programmable, so that I can set it to move up by 5cm after 1min, move up again by 5cm after 10min, and finally go back into the
starting position after 30 min (times are given as example).
Does anything like this exist? What is something that comes close to it? Shouldn't be expensive, considering the simple operations it has to do.
Thanks for your attentionDr.Bob - 18-10-2016 at 09:15
Sounds like a Jiffy jack (lab type jack stand) connected to a stepper motor, like those used in a x-y-z type cad cam machine or a syringe pump.
Should be very easy to find something like that. Even the newer rotovaps have an electric lift on the water bath that might work. Muffin Man - 18-10-2016 at 10:17
I mean, could it be as simple as a servo with a long arm to move a very small weight ?
Very low weight, like 5g.
I need to use it as a dip coater, but since I want to make the procedure reproducible with the least amount of human error, I wanted a programmable
one that I could set up at start, then attach the platelet to the "arm", and abandon it for 1h.
I never worked with such appliances so I don't even know how such device is called.
Also I'm not an expert in electronics. I can play around with the program itself, but not the electronic components.
I searched that servo you mentioned, but I don't get how it works. Could you elaborate for the ignorant?Sulaiman - 19-10-2016 at 08:11
just search for 'linear actuator' or 'door opener'
[Edited on 19-10-2016 by Sulaiman]
As I understand, this linear actuator has a mid rod that moves up and down thanks to lateral screws.
What I'd like to understand is: is there something I can attach to the end of that rod? In my case, this appartus should be held head-down, because I
have to append my lamina on it. I've drawn a schematic of what I want to build:
This device has to be programmable, so that I can set at which time it has to go down, for how much time it has to stay down, and after how
much time it has to go up.
I looked up some items on ebay and most of them have a remote control with switch positions, however I cannot find one that is automated and does his
thing on his own after having been programmed.
Will this work for my application?
[Edited on 20-10-2016 by Metallus]Sulaiman - 22-10-2016 at 05:56
I started a long reply but it would be easier if we knew if this is for
continuous industrial production
hobby production
or
short-term hobby use
and
can you programme any microcontroller?aga - 22-10-2016 at 10:53
Arduino, 'standard' ardunio stepper motor + interface board, a bit of string (or steel rope if you prefer) and a pulley at the top.
Teensy bit of coding and you're done.
If the standard stepper is not poweful enough, despite the gearing (which might be the case if it's a 5kg weight) then go to a NEMA 23 stepper or
bigger, or possibly just a small block & tackle arrangement.
With something like an arduino, you'd have the option to set the Times as you like, or add in sensors to make it go up and down when it Should, rather
than just at set times. Metallus - 24-10-2016 at 03:12
I started a long reply but it would be easier if we knew if this is for
continuous industrial production
hobby production
or
short-term hobby use
and
can you programme any microcontroller?
I already wrote what I need it for in the post above: I need a semi-automatic dip coater for lightweight laminas (5g) and the process lasts ca 1h. At
the moment I do it manually, but it's a rather boring procedure because I have to wait intervals of 5-10mins doing nothing.
I'm testing how each parameter influences the amount of stuff I can deposit on my laminas, so I guess it would fit the "hobby production"?
When it comes to programming, I know the basics of C and the logical functions and/or if/else/then, but it's been 5y since I last touched C language.
I think I would be able to do it after spending a day after it.
@ Aga
The device you described seems to fit the bill. As I said before, the weight is very low and I doubt it will ever exceed 10g.
One of the items that got linked in the first posts were very attractive because of the low price (I had planned on spending max 100€). I don't need
anything sophisticated or super high quality/performance. Just some motor that pulls up and down and is programmable, like an oven.
You know that in modern ovens you can set up a temperature ramp and hold up time? I'd need something like that, where you set up the holding time, at
which speed it has to pull up and for how long it has to stay up. If it came with a similar interface it would be perfect.
A stepper motor to which I can append a wire will do the job just fine. Just wanted to know if there was a premade microcontroller/whatever that has
an inbuilt program that lets me set up the different steps.
[Edited on 24-10-2016 by Metallus]
Muffin Man - 24-10-2016 at 03:59
Since you can program, have you thought about the Lego Mindstorms kits? I was able to get a whole kit for free through Kijiji but they are pretty rare
at that price. You would be able to snap together a suitable framework with a motor and gear reduction if necessary.
This would not be as cheap as an Arduino and stepper motor combination but there are tons of other stuff that you could do afterwards.Sulaiman - 24-10-2016 at 04:31
Because my next question was "where can I find those time delayers to put before appliances in order to stop/start them at given intervals"?
I had one of those things that worked with intervals of hours and I used it once to make my pump start up and work for 1h, then stop for 3h, for 3
days.
Now I thought of buying one that worked with minutes/seconds and the ones you linked look exactly like it.wg48 - 24-10-2016 at 06:33
Here is a two channel programmable timer 0.1s to 9,999s
In the listing that I pointed to, only the 220 Vac versionis are 1 to 30 minutes,
but a wide range of voltage and timer ranges are generally available.
Relay logic is simple, contacts are normally closed (NC) or normally open (NO)
NO contacts in parallel = OR
NO contacts in series = AND
NC contacts in parallel = NAND
NC contacts in series = NOR
etc.
Two changeover contact sets (DPCO/DPDT/2P2W) can make a dc motor reversing switch.
