Pneumatics @ 24V stamp at 5V. How to interface?
Hello Thanks for the input -
I'm working on a Midi based robotic drum kit. It uses pneumatic cylinders to strike the drum heads. Stamps (andPICS) run at +5Volts. The Solenoids that I'm trying to interface with are really just simple switches, However they run at 24Volts. Is there a simple way to connect to them?
I'm working on a Midi based robotic drum kit. It uses pneumatic cylinders to strike the drum heads. Stamps (andPICS) run at +5Volts. The Solenoids that I'm trying to interface with are really just simple switches, However they run at 24Volts. Is there a simple way to connect to them?
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Comments
Dave
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Dave Andreae
Tech Support
dandreae@parallax.com
Http://www.parallax.com
·
wow thanks for the comprehensive reply! THis is super helpful!!!
one last question on the ULN2003's... will they handle 24VOLTS? the data sheet lists the Vo= 50 and the Vi as 30. This means that i can use this safely to run the INs at +5volts and the "other side" the outs and "supply" at 24 volts correct?
that would be fantastic and so simple....
thanks in advance
elliott
·· What is the current rating of the 24V devices you mentioned?
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Chris Savage
Parallax Tech Support
csavage@parallax.com
the solenoids (8 of them) are rated: Valve coils are rated 24 VDC 6 watts each
elliott
·· That means that they draw approximately 250mA.· I would estimate high.· The ULN can handle up to 500mA per output, but not all driven at the same time.· How many do you expect to have going at once, and what is the estimated duty cycle?
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Chris Savage
Parallax Tech Support
csavage@parallax.com
·· It could work.· In a few areas it seems a little close on current tolerances, but you can always test actual current draw before committing to anything.· I would definately test the solenoids current draw instead of basing things on the Power/Voltage calculation.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Post Edited (Chris Savage (Parallax)) : 8/15/2005 2:45:43 PM GMT
first of all SINCERE THANKS FOR all the help with this issue!!! On digikey's site I found a Darlington chip thats rated to 1.5 amps. Would this solve the problem?
ULN2067B IC SWITCH QUAD DARL 16 POWERDIP STMicroelectronics
NPN - Darlington
50V
1.5A
4 Darlington
16-DIP
DIGIKEY PART# 497-2350-5-ND
·· Oddly the chip would seem to have a robust darlington system, but yet the max power dissapation is listed at a mere 4.3W.· Your solenoids draw 6W each.· I'd have to look into it more.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
How much did your solenoids cost u and·can you control the presure or are they just on/off?
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Best Regards
Manuel C. Reinhard
my solenoids were an absolute steal. they're from CandH sales. They sell used equipment. There are eight solenoids coupled to a distribution manifold, with a 60 psi regulator included. I'm currently workin gon Version 2.0 of the drum kit. In the first version, I bought all of the solenoids and valves from Mcmaster carr. The valves were 25 bucks a pop. the Solenoids were similar. the manifold was like 90 bucks and on and on... and no they are simple on and off solenoids. The "velocity" sensitive do exist, however in my research I have only found them new for over $400 each.
From my perspective there are enough engineering challenges with just the stick mechanism. I eventually want to find some used velocity sensitive solenoids. but given that this is my second attempt at creating a the kit I realize that this is a very long term process.