PDA

View Full Version : how to control a high voltage stuff with microcontroller



m_ghv_geo
03-31-2010, 11:28 AM
hi all i goat my first microcontroller yesterday as a learning kit at radio shack it is called parallax basic stamp bc-2 item # 90005
i was playing, discovering and learning with it a few days but know am and up with tons of questions

first question is how can i control lets say a 120v lamp with it http://forums.parallax.com/images/smilies/eyes.gif ?

next question is this thing only has 9 volt Battery sou its max output is 9 volts lets say i want to control a few 12 volt motors with it how can i do that?

i can figure out by my own how to program but i need help to how to connect higher voltage stuff to microcontroller?

http://forums.parallax.com/images/smilies/blush.gif please go easy on me i am new in this microcontroller world

Mike Green
03-31-2010, 12:19 PM
1) An ordinary 9V battery cannot put out enough current for a motor more than for a few minutes. It simply doesn't have the capacity. You need an adequate power supply.

2) Nuts and Volts Column #6 discusses how to control higher voltages and higher currents using a Stamp I/O pin. Download it from Parallax and read it.

3) Controlling any kind of AC device is potentially very dangerous. You need to know what you're doing. For 120VAC devices up to a few Amps, you can use an appropriate relay or SSR (Solid State Relay). Parallax makes an Industrial Control Board that provides for several such relays. EFX-TEK also has a Solid State Relay board. Using either one is still potentially very dangerous. You can get killed.

m_ghv_geo
03-31-2010, 01:46 PM
thanks for second answer i will try to find it
it would been good if you wrote a direct link to that page thx any way

m_ghv_geo
03-31-2010, 02:02 PM
i found Nuts and Volts volume #6 but i have trouble finding "how to control higher voltages and higher currents using a Stamp I/O pin"http://www.parallax.com/Resources/NutsVoltsColumns/NutsVoltsVolume6/tabid/449/Default.aspx



Mike Green said...
1) An ordinary 9V battery cannot put out enough current for a motor more than for a few minutes. It simply doesn't have the capacity. You need an adequate power supply.

2) Nuts and Volts Column #6 discusses how to control higher voltages and higher currents using a Stamp I/O pin. Download it from Parallax and read it.

3) Controlling any kind of AC device is potentially very dangerous. You need to know what you're doing. For 120VAC devices up to a few Amps, you can use an appropriate relay or SSR (Solid State Relay). Parallax makes an Industrial Control Board that provides for several such relays. EFX-TEK also has a Solid State Relay board. Using either one is still potentially very dangerous. You can get killed.

Ron Czapala
03-31-2010, 08:06 PM
See Figure 6.3 in the article. The appropriate relay (solid state or mechanical) can control high voltages.

The Basic Stamp and transistor drive the relay. The diode is critical to protect them when the relay coil power is disconnected.

Chris Savage
03-31-2010, 09:25 PM
Parallax carries a Digital I/O Board Kit (http://www.parallax.com/Store/Accessories/Other/tabid/167/ProductID/658/List/0/Default.aspx?SortField=ProductName,ProductName)tha t controls up to 8 relays, either mechanical or solid-state. This kit requires soldering. If your soldering skills are fairly decent then this is the ideal way to control 120VAC devices and can be done serially or parallel using a simple command such as HIGH 0. Take care.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage

Parallax Engineering

rev
03-31-2010, 11:30 PM
This is a nice and realatively cheap solid state relay that can handle a few amps @110V, and doesnt require a diode or transistor on the low voltage end, all you have to do is get the polarity right.
A very quick and easy way to start controlling high voltage right away with your basic stamp.
http://www.grainger.com/Grainger/items/6C900?Pid=search

Chris Savage
04-01-2010, 02:16 AM
rev, the SSR we carry handles 8A @ 125V. Looks like we just got sold out of them, but they're as easy to control as an LED. They also fit nicely into the Digital I/O Board I mentioned.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage

Parallax Engineering

m_ghv_geo
04-01-2010, 02:56 AM
thanks all for those info's my soldering skills are rely bad i need some one to teach me how to use soldering maybe i will go to "nyc resistor" to learn properly but for know i have to learn a bought the transistors how they work and how to use them can one of you provide a link to the page which will help me understand their principals

rixter
04-01-2010, 05:09 AM
m_ghv_geo,

You need to look at Column #6, not volume #6. Column #6 is in Volume #1: ...... http://www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol1/col/nv6.pdf

Rick

eod_punk
04-01-2010, 10:20 AM
M_ghv_geo I found these videos on eagle to be helpful, maybe his soldering tutorials cam help you as well.

http://tangentsoft.net/elec/movies/

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
There is no problem that can't be solved with a suitable amount of explosives!

EOD Memorial (http://www.eodmemorial.org)

m_ghv_geo
04-01-2010, 01:39 PM
thank you eod_punk

m_ghv_geo
04-01-2010, 01:53 PM
only think what am i looking for is how to use the transistor does someone knows really really simple project were transistor is used it will be good if transistor will be 2n3904 thank you all for your wonderful answers