Accelerometer | ADC | ADXL | Adxl20 | AVR | BasicStamp | BX-35 | BX28 | BX35 | COM3 | Compiler | Downloader | EEPROM | Electromagnet | GetADC | GP2D1 | GPS | I2C | IDE | Keypad | LCD | LCD+ | MIDI | Motors | Multitasking | Netmedia | Networking | PCB | PID | PlaySound | PWM | Relays | RTC | Servo | ShiftOut | SitePlayer | SPI | Stack | Timer | USB

I asked the group before (a week or so ago) and never got a response - i thought that this was on topic - if i'm wrong, let me know. i'm new to robotics and i want to get a mosfet to build into my project - but i know i'm going to need the groups help with writing code (still haven't had a reason to begin playing around with the editor), and i'll need the groups help with interfacing whatever switching device i get to the bx24. so, for that reson (because i'll be asking for code samples etc.) i was hoping someone could tell me a specific mosfet (model number, pin count) or other switching device for differential and PWM that you have used and can assist me with after i get my hands on one. I hope someone can give me some advice... :^) __________ miguel martin http://olio43.virtualave.net/bots/robot.html (some of my work so far) http://www.enkaschools.com/main/preschool.html (school)

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

> Well Here is a PICT of a Good mosfet drive circuit, works with TTL contol and i'm sorry, but what does PICT mean? and what is TTL? are those the product type names of the mosfet? >Depending on the mosfet you can really > control a large amount of current with them also, oh, that probably means that pict and ttl aren't mosfet names - are there any certain mosfets that i'll need to get (or aviod) to work with your circuit? > p.s. I also have a schmatic on a TTL speed control that you could easly hook up > to this circuit. Let me know if you are interrested. thanks. i am. __________ miguel martin http://olio43.virtualave.net/main.html http://www.enkaschools.com/main/preschool.html

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

Are you going to use this to drive motors? What kind of current draw do you need? Does it have to be a mosfet, or are you just looking for a good way to switch PWM? Even small DC motors can pull gobs of current. To test your motors for their maximum current drain, check them at their running voltage at *stall*. ie. hold the shaft. A bit more information and you may get lots of advice... Duncan

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

> From: Tom Umble <> > A good source of Robotic Info. including motor > controls > is Nuts & Volts Mag. the February issue has a column > on H Bridge motor controls, in the Robotic section i live in turkey and it's impossible to find mags of any kind unless they are totally main stream like Time - maybe a few for internet junk. and nuts & volts doesn't make their mags available on line like Wired does - all i see are the collumn headlines for feb. when i move back to the states, i'll subscribe i'm sure. __________ miguel martin http://olio43.virtualave.net/main.html http://www.enkaschools.com/main/preschool.html

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

Miguel Martin wrote: > From: "Miguel Martin" <> > > I asked the group before (a week or so ago) and never got a response - i > thought that this was on topic - if i'm wrong, let me know. > > i'm new to robotics and i want to get a mosfet to build into my project - > but i know i'm going to need the groups help with writing code (still > haven't had a reason to begin playing around with the editor), and i'll need > the groups help with interfacing whatever switching device i get to the > bx24. > > so, for that reson (because i'll be asking for code samples etc.) i was > hoping someone could tell me a specific mosfet (model number, pin count) or > other switching device for differential and PWM that you have used and can > assist me with after i get my hands on one. > > I hope someone can give me some advice... Well Here is a PICT of a Good mosfet drive circuit, works with TTL contol and even has a speed control! The speed control is a Pulse Width modulator type that really works great! You would have to make 2 of these for your differential drive, but that shouldn't be a problem....Depending on the mosfet you can really control a large amount of current with them also, some to 10+ Amps I believe! This Circuit came out of a book called Robot Builder's Bonanza 99 Inexpensive Robotics Projects, by Gordon Mccomb! This book is excelent for the robot beginner! Hope this helps! p.s. I also have a schmatic on a TTL speed control that you could easly hook up to this circuit. Let me know if you are interrested. [Non-text portions of this message have been removed]

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

From: > Are you going to use this to drive motors? What kind of current draw do > you need? yes. for small motors. I have a handful of different sizes - but right now I've built something using 2- 3 V motors ( I believe) - I pulled them out of cheep wire control cars. >Does it have to be a mosfet, or are you just looking for a good > way to switch PWM? I can say this: if you guys tell me it has to be a mosfet, then it does. if not, then I've got no reason *not* to use something else. I just assumed that fets were the way to go. all that I've read so far references fets...so... >Even small DC motors can pull gobs of current. To test > your motors for their maximum current drain, check them at their running > voltage at *stall*. i.e.. hold the shaft. A bit more information and you may > get lots of advice.. I also have a few I bought from RS - the smaller one (very similar to the one I've used from the small car) says "1.5-3.0 V speed (load)8300 RPM max" on the package. I have two larger motors from RS that say: "12vdc motor 1.3 A, speed (noload) 15,200 RPM, speed (load) 11,5000RPM, current (load 1.3 A, torque 56 rm.cm" [it's too bad that RS can't package the smaller motors with the same detailed info that they include for the larger ones. it would be very helpful, esp. for beginners.] as for the motor that I don't know anything about - I put the test probes of my meter on the motor's poles and took a reading while holding the shaft (not an easy task I should say - I need five hands for all of that :^) and the result - I believe - was 4V while holding the shaft - and 5.25V free running - powered by a 4.8V rechargeable RCcar battery. ( the recharger for the batter is a 6V 180mA transformer - if that helps at all.) my meter was set at DCV15 - the lowest setting. the next up is 150 so i'm pretty sure i read it correctly. I can't find the current because I can't measure R with my crummy little meter. I only have one ohm setting for Rx 1K ohm, and when I try measuring the motor across poles, without any wires or V connected - the meter reads 0 ohms. I zeroed the meter first, didn't touch the probes or poles while reading, etc.... *can* I find current w/out knowing R? the answer's "NO", isn't it? will that matter for what we're doing now? thanks so much guys. sorry I didn't give enough information the first time around. I hope this is better... ________ miguel martin http://olio43.virtualave.net/main.html http://www.enkaschools.com/main/preschool.html

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

A good source of Robotic Info. including motor controls is Nuts & Volts Mag. the February issue has a column on H Bridge motor controls, in the Robotic section Page 33. Also the Stamp Application page 17 has "Motor Control Made Easy". March has follow up column as well. Hope this helps.The have a Web site as well www.nutsvolts.com tom --- wrote: > From: > Are you going to use this to drive motors? What > kind of current draw do > you need? Does it have to be a mosfet, or are you > just looking for a good > way to switch PWM? Even small DC motors can pull > gobs of current. To test > your motors for their maximum current drain, check > them at their running > voltage at *stall*. ie. hold the shaft. A bit more > information and you may > get lots of advice... > > Duncan ------------------------------------------------------------------------ > GET A NEXTCARD VISA, in 30 seconds! Get rates > as low as 0.0% Intro APR and no hidden fees. > Apply NOW! > http://click.egroups.com/1/975/4/_/565855/_/953931021/ > ------------------------------------------------------------------------ > __________________________________________________

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

> From: "Dan Creagan" <> > them becomes a big problem. Jameco has some very good, low current, >good ok. i'll see what happens with an overseas order - but customs and the post office may steal them :^( > Once you get motors, then you can use L293D or SN755410 chips as H >bridges - i just got back from a 6 hour trip to the closest electronics stores in the city (this place is huge and it's organized like a rolladex - all like things are in one place) -- -anyway, i did get a few fets to have so that i can at least ask the group about. they were super cheap, so i don't care if i can't use them now. numbers (with barely any specs): i got two IRF 630 fets, 9A, 200V and a few BC264 N-Fets (NF-V, ra, 30V, 1dss>2mA, Up<1,6V) everyone that i met today told me i *had* to know the number first - mostly cause those guys know less about them than i do. (no joke) i tried explaining about the motor specs etc that i posted this am - but they keep saying i have to have a number - - - and i don't have any catalogues with numbers and specs (except for the RS, but if i'm supposed to stay away from that...well..) > mine from BG Micro. do they have a url? i tried bgmicro.com, no luck. thanks. maybe today wasn't a complete waste of time. :^) miguel martin http://olio43.virtualave.net/main.html http://www.enkaschools.com/main/preschool.html

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

If you want to make your life easier, get some better motors. The Radio Shack and RC car motors are cheap and pull too much juice for most robot control applications. Also, they are way too fast and low torque so taming them becomes a big problem. Jameco has some very good, low current, good efficiency motors and they are a button click away. Look at the Hsiang Neng motors and carefully pick your gear ratio. I usually go to something about 100:1 if I'm just experimenting. But 60:1 is good for a moderately fast robot. Once you get motors, then you can use L293D or SN755410 chips as H bridges - a very good solution. If you want to stay with the RS stuff or you want to use that multi-amp thingy from the RC car, then you can use an L298 which will handle a couple of amps. You can get L298's from several places, I got mine from BG Micro. They require fast diodes so don't use 1N4004's (RS stuff), but something like 1N4935s (also available from BG Micro). Or, you can roll your own with discreet components - but it is a lot nicer to go with the one chip solution if possible. Dan Creagan PS: my new (yet again) web site is finally going to have a domain name. It comes with yet another change of IP address. Any previous references will be invalid after the end of the month. The new site is http://academic1.bellevue.edu/robots/sigrobots.html . ----- Original Message ----- From: Miguel Martin <> To: <> Sent: Friday, March 24, 2000 3:46 PM Subject: Re: [BasicX] differential drive devices with bx24 > From: "Miguel Martin" < > From: > > > Are you going to use this to drive motors? What kind of current draw do > > you need? > > yes. for small motors. I have a handful of different sizes - but right now > I've built something using 2- 3 V motors ( I believe) - I pulled them out of > cheep wire control cars. > > >Does it have to be a mosfet, or are you just looking for a good > > way to switch PWM? > > I can say this: if you guys tell me it has to be a mosfet, then it does. > if not, then I've got no reason *not* to use something else. I just assumed > that fets were the way to go. all that I've read so far references > fets...so... > > >Even small DC motors can pull gobs of current. To test > > your motors for their maximum current drain, check them at their running > > voltage at *stall*. i.e.. hold the shaft. A bit more information and you > may > > get lots of advice.. > > I also have a few I bought from RS - the smaller one (very similar to the > one I've used from the small car) says "1.5-3.0 V speed (load)8300 RPM max" > on the package. I have two larger motors from RS that say: "12vdc motor 1.3 > A, speed (noload) 15,200 RPM, speed (load) 11,5000RPM, current (load 1.3 A, > torque 56 rm.cm" > > [it's too bad that RS can't package the smaller motors with the same > detailed info that they include for the larger ones. it would be very > helpful, esp. for beginners.] > > as for the motor that I don't know anything about - I put the test probes of > my meter on the motor's poles and took a reading while holding the shaft > (not an easy task I should say - I need five hands for all of that :^) > and the result - I believe - was 4V while holding the shaft - and 5.25V free > running - powered by a 4.8V rechargeable RCcar battery. ( the recharger for > the batter is a 6V 180mA transformer - if that helps at all.) my meter was > set at DCV15 - the lowest setting. the next up is 150 so i'm pretty sure i > read it correctly. > > I can't find the current because I can't measure R with my crummy little > meter. I only have one ohm setting for Rx 1K ohm, and when I try measuring > the motor across poles, without any wires or V connected - the meter reads 0 > ohms. I zeroed the meter first, didn't touch the probes or poles while > reading, etc.... *can* I find current w/out knowing R? the answer's "NO", > isn't it? > > will that matter for what we're doing now? > > thanks so much guys. sorry I didn't give enough information the first time > around. I hope this is better... > ________ > miguel martin > http://olio43.virtualave.net/main.html > http://www.enkaschools.com/main/preschool.html > > > ------------------------------------------------------------------------ > PERFORM CPR ON YOUR APR! > Get a NextCard Visa, in 30 seconds! Get rates as low as > 0.0% Intro or 9.9% Fixed APR and no hidden fees. > Apply NOW! > http://click.egroups.com/1/2121/4/_/565855/_/953977950/ > ------------------------------------------------------------------------

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

The address called http://www.bgmicro.com/ resolves correctly from my end. They are a surplus dealer and I've had good luck with them. Nice folks. Dan -----Original Message----- From: Miguel Martin <> To: <> Date: Saturday, March 25, 2000 12:45 PM Subject: Re: [BasicX] differential drive devices with bx24 >From: "Miguel Martin" < > >> From: "Dan Creagan" <> > >> them becomes a big problem. Jameco has some very good, low current, >good > >ok. i'll see what happens with an overseas order - but customs and the post >office may steal them :^( > >> Once you get motors, then you can use L293D or SN755410 chips as H >>bridges - > >i just got back from a 6 hour trip to the closest electronics stores in the >city (this place is huge and it's organized like a rolladex - all like >things are in one place) -- -anyway, i did get a few fets to have so that i >can at least ask the group about. they were super cheap, so i don't care if >i can't use them now. > >numbers (with barely any specs): >i got two IRF 630 fets, 9A, 200V >and a few BC264 N-Fets (NF-V, ra, 30V, 1dss>2mA, Up<1,6V) > >everyone that i met today told me i *had* to know the number first - mostly >cause those guys know less about them than i do. (no joke) i tried >explaining about the motor specs etc that i posted this am - but they keep >saying i have to have a number - - - and i don't have any catalogues with >numbers and specs (except for the RS, but if i'm supposed to stay away from >that...well..) > >> mine from BG Micro. > >do they have a url? i tried bgmicro.com, no luck. > >thanks. maybe today wasn't a complete waste of time. >:^) > > miguel martin >http://olio43.virtualave.net/main.html >http://www.enkaschools.com/main/preschool.html > >------------------------------------------------------------------------ >Good friends, school spirit, hair-dos you'd like to forget. >Classmates.com has them all. And with 4.4 million alumni already >registered, there's a good chance you'll find your friends here: >http://click.egroups.com/1/2623/4/_/565855/_/954010164/ >------------------------------------------------------------------------

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )

just a followup question - I bought a handful of 5V power relays , 555 timers, 556 timers (I've seen several sites which have tutorials about using the last two items in robotics - anyway...) anyone have any success with using these things for motor direction control? __________ miguel martin http://olio43.virtualave.net/main.html http://www.enkaschools.com/main/preschool.html

(You need to be a member of basicx -- send a blank email to basicx-subscribe@yahoogroups.com )