TreadBot

**dragons_fire** · - 10th April 2007, 23:28

Here are a couple pics of the robot im working on. I do this just for fun, and for the challenge of getting it all together and working the way i want it too...

the chassis is made from 1/8" polycarbonate and 3 layers of 6oz glass cloth. the wheels are turned from 3/4" aluminum. the battery pack is a 7.4V 730mAh li-poly RCplane battery.

A better pic of the chassis construction. you can also see the hall effect sensor and the magnet in the wheel. i think i will probably add 2-3 more magnets around the wheel for more resolution.

robot with mock-up of PCB. it uses a PIC18F6585 controller, Pololu Micro Dual Serial Motor Controller, Rogue Robotics uMMC Serial Data Storage Module with 1Gig Card, memsic 2 axis accelerometer and a Paralax Ping ultrasonic sensor.

Im still adding 4-8 IR detectors for base station detection, Lynx 433MHz data transmitter, temp and air pressure sensors (just for the fun of it).

so now I need a mission for it and i cant think of anything... the memory card is going to be for mapping data, so it can remember where its been, and easily get back to any of those places. It cant climb stairs and doesnt have enough clearance for outdoor use.

if anyone has any ideas or opinions, i would be glad to hear them...

Danny

skimask · - 11th April 2007, 00:23

Put a couple of IR LEDs on the cat blipping out a signal for the rover and have it follow the cat around ALL DAY!!! Then when the batteries run down, since it's got the house mapped, it can find it's way back to the charging station where it doesn't plug into anything...it 'hovers' over a charge transfer coil (magnetic recharging?)...waits until it's recharged. When it's recharged, it looks thru its map (all the while it's been chasing the cat, it marks where the cat has been the most), goes to the spot or area where the cat usually hangs out and then POUNCES on the cat!

**dragons_fire** · - 11th April 2007, 01:28

HAHA!!! thats a great idea... Exactly the kind of ideas im looking for... Only probelm is that i dont have a cat (and dont want one), and the dog sleeps on hte couch all day where this thing cant get too...

the mapping idea is just for the challenge of trying it, but im still debating my method of using the revolutions to tell how far its gone.. the room (the main floor of the house) has linoleum, hardwood and a couple rugs.. i can almost guarantee its going to slide trying to go from one to the other.. it looks like i may need to add a compass into it somehow, or add IR transmitters on different frequencies around the room, and have the robot detect them and figure out where it is...

im curious as to what other people think about what it can do, or how to figure out where it is...

**dragons_fire** · - 11th April 2007, 01:47

we also have the western canada robot games being held in my city, so i was thinking about making it for the minesweeper competition. its a great idea, but i dont think i could have it ready by the competition this year, and i dont want to build it just to wait until next year...

skimask · - 11th April 2007, 02:23

Originally Posted by dragons_fire

the mapping idea is just for the challenge of trying it, but im still debating my method of using the revolutions to tell how far its gone.. the room (the main floor of the house) has linoleum, hardwood and a couple rugs.. i can almost guarantee its going to slide trying to go from one to the other.. it looks like i may need to add a compass into it somehow, or add IR transmitters on different frequencies around the room, and have the robot detect them and figure out where it is...

im curious as to what other people think about what it can do, or how to figure out where it is...

Mapping - are you using stepper motors or regular 'just add volts and it spins' motors? Regular motors - good luck getting them to spin EXACTLY the same speed to go straight! Not saying it's impossible, but it'll be tough without good electronics. And what happens when the treads slip on the floor? The 'bot could think it's moving forward, when it's actually getting nowhere. Keep an eye on current draw could help with that. Motor draws X current, it's moving normally, motor draws 2X current, tracks are probably hanging up, motor draws .5X current, tracks are probably slipping like they're on ice.

Compass - magnetic compass 'could' work. How about an RF/IR link? A master RF TX sends out a pulse at X intervals, say 10 seconds. 1 second later, an IR LED on wall X1 pulses, 1 second later, an IR LED on wall X2 pulses, and so on and so on. The 'bot 'hears' the master pulse and starts looking for IR pulses. Depending on which IR sensor sees it and at what time, it can figure out which way it's pointing, limited accuracy of course.

**dragons_fire** · - 11th April 2007, 02:42

the motors are just regular brushed motors, they have a gear ratio of 298:1 which equals out to 71RPM and 30oz/in of torque. im using a serial dual motor controller, and with the hall sensors, i should be able to adjust the motors to get it to move straight forward...

my big issue, is that it will turn better on shiny hardwood, than it will on carpet, so if i tell it to turn 90*, it will turn 95* on wood, and 80* on carpet.. what i was thinking with the IR link, was to have 3 transmitters around the room, and then have 16 (or more) sensors around the top of the bot, and it could somewhat triangulate where it is by the angles to all 3 transmitters. it could do that maybe every 5 minutes, just to make sure its where its supposed to be...

skimask · - 11th April 2007, 02:59

Originally Posted by dragons_fire

the motors are just regular brushed motors, they have a gear ratio of 298:1 which equals out to 71RPM and 30oz/in of torque. im using a serial dual motor controller, and with the hall sensors, i should be able to adjust the motors to get it to move straight forward...

my big issue, is that it will turn better on shiny hardwood, than it will on carpet, so if i tell it to turn 90*, it will turn 95* on wood, and 80* on carpet.. what i was thinking with the IR link, was to have 3 transmitters around the room, and then have 16 (or more) sensors around the top of the bot, and it could somewhat triangulate where it is by the angles to all 3 transmitters. it could do that maybe every 5 minutes, just to make sure its where its supposed to be...

Motors - That kind of gear ratio sounds a bunch better than direct drive. Should be able to keep track of that fairly well.

Turning/mapping/whatever - too bad a guy couldn't 'easily' add a circuit like an optical mouse. Ya get 2 of those, one at the front in the middle, one at the back in the middle, you can do some math to figure out how far the 'bot actually turned.

This could turn out to be a lllooonnnggg thread...

**dragons_fire** · - 11th April 2007, 03:38

definately could be a long thread... there are a bunch of different ways to do everything... like figuring out how far it turns... there is: gyros, compass, "mouse balls", hall sensors on the wheels, IR base stations (celestial navigation), and im sure there has to be another 100 ways that i didnt mention...

right now im thinking i might just make it so it hides from light (photophobic) during the day, and then comes out to play at night... at least until i can come up with something better for it to do...

skimask · - 11th April 2007, 03:48

Originally Posted by dragons_fire

right now im thinking i might just make it so it hides from light (photophobic) during the day, and then comes out to play at night... at least until i can come up with something better for it to do...

Just like in Gremlins...(you said 'mouse balls').

**dragons_fire** · - 11th April 2007, 04:05

HAHA i havent seen that movie in forever....

**mackrackit** · - 11th April 2007, 08:29

Originally Posted by skimask

Turning/mapping/whatever - too bad a guy couldn't 'easily' add a circuit like an optical mouse. Ya get 2 of those, one at the front in the middle, one at the back in the middle, you can do some math to figure out how far the 'bot actually turned.

Why not use a "ball" mouse. xy axis could keep track of turns to. Might take a bigger ball to go across the floor. The optos in the mouse are easy to use too.

**dragons_fire** · - 11th April 2007, 15:00

i didnt know computer mouses had balls??? i thought they all used lights and lasers!!!!! :P

i like the idea, but i think it would have problems getting up from the hardwood to the rug, (about 1/4" bump) and still be somewhat accurate with out using a massive ball, and i dont really have much room for a big ball...

Not trying to put down all the ideas, im just trying to get some ideas and start a conversation about different ways to do it... its really interesting how many ways there are to do different tasks and some of the weird ways that no one would ever think of.

**mackrackit** · - 11th April 2007, 20:50

"i didnt know computer mouses had balls???"

That is how you tell the difference, male or female... You really are a NEWBIE

The ball and optos could mount on a spring loaded platform in the front or back.

This is an interesting problem, in my work we use doppler radar along with gps for applicators that move across the field at 20 mph. Even then things could end up depending on plowed or disked - satellite coverage - etc- 50 cm off in a couple of km.

Run a "female" mouse over paper with lines and you will see the problems with that. I bet the RF idea with beacons would be the most accurate.

If I think of something very small and cheap will let you know.

skimask · - 11th April 2007, 21:00

Awhile back I had an idea for tracking a push type lawn mower.
I'd put IR LED transmitters in the 4 corners of a square lot, each with it's own pulsing IR code. On the top of the mower would be an IR detector that could move 360 degrees. I slowly go 'round until I saw 1 of the IR LEDs, mark that angle, and keep going until I saw at least 2 of the 4 IR transmitters. As long as I had two angles to work with, I could triangulate my position inside the square lot (ignoring the fact that there are really 2 places an object could be in 2D space using that method, one inside the square, one outside). The more the IR LED transmitters, the better the accuracy, and the better the chances I'll see them if the platform was to somehow get off level.

**dragons_fire** · - 12th April 2007, 00:19

yup im a newbie... im also almost to young for that kinda stuff!!! haha

it doesnt have to be perfect, its just for fun.,.. im thinking that although i love the size of this thing, it might be a tiny bit too small for experimenting with all this stuff...

Skimask, thats exactly the same thing i was talking about.. haveing a bunch of base stations around, that all emit different pulses, and have the robot decode that, and triangulate where it is...

im hoping i can fit everything into the pic now.. im using the 18f6585 because it had the specs i wanted for another project that fell through... so mow i have it left over, and would like to use it...

heres the specs:
48 k bytes 24 k words
1024 eeprom
53 i/o 12adc

i would just like to say, you guys have all been great. i have been on some other forums (mostly for other stuff like offroading and RC stuff) and people just tell you that there is only one way to do things, and that it wouldnt be worth the effort to attempt to do certain things..

skimask · - 12th April 2007, 00:29

Originally Posted by dragons_fire

it doesnt have to be perfect, its just for fun.,.. im thinking that although i love the size of this thing, it might be a tiny bit too small for experimenting with all this stuff...

Well, you could always go vertical with the PCBs, stack them with interconnecting header pins for power and use some IR emitter/detector pairs to communicate data, or whatever...then again, that might make the thing too tall to go under stuff...

Skimask, thats exactly the same thing i was talking about.. haveing a bunch of base stations around, that all emit different pulses, and have the robot decode that, and triangulate where it is...

Might be a bit of an MCU intensive process, might involve floating point math, then again, might be able to make it 'just good enough' and not 'perfect'.

As far as the PIC goes, the only thing I see limiting is program space. And when that happens, you could do what I said earlier, offload some processing to a daughterboard vertically stacked.

This almost sounds like too much fun! I outta be building one myself...as soon as my 'lab' in the basement gets done.

**dragons_fire** · - 12th April 2007, 04:23

right now (without the PCB and components) it will fit underneath 3/4 of the doors in my house!!! the only think that could stop it is stairs!!!

I was thinking i could stack the boards 2 or 3 high, and that would give lots of room for all the sensors and other "gadgets" that i would like to add.. It would also be a lot smaller if i went with all SMT stuff and make everything myself instead of using prebuilt components. at the moment in designing it to use a serial motor driver, which uses a 9-pin header, a pic12f629 and a dual h-bridge chip. if i put the h-bridge directly on my board, and ran it off of the 18f6585, it would be tiny... at the moment, im using it for simplicity, it uses a 4byte command to control direction and speed or both motors.

With the mapping, i was thinging of doing it somewhat like a micromouse would. the room would be divided into little squares, and then it would decide which squares it can go in, and which ones it cant..

i would like to make a list of different "missions" for robots, not just for me, but for anyone else that just plays around with this stuff. to start, here are some of the things im working on, and some others that i would like to make someday:
workin on:
house mapping
cave exploring - lots of old mines around my place
snowplow

others:
photophobic
phottropic
lawnmower
sumo competition
micromouse
firefighting
minesweeping

if anyone has any others, lets hear them... im sure there are lots of other things out there...

**dragons_fire** · - 12th April 2007, 04:47

this is a neat idea, a little expensive for hobby robotics though....

http://www.robotshop.ca/home/product...ar-system.html

**mackrackit** · - 12th April 2007, 09:06

Originally Posted by dragons_fire

this is a neat idea, a little expensive for hobby robotics though....

http://www.robotshop.ca/home/product...ar-system.html

Looks similar to Skimask idea, I was going to suggest sonar also. I have a cheap sonar measuring tape that is pretty accurate. Use two to have a location.

Let us know what you plan to use and we will see if we can help.

**dragons_fire** · - 12th April 2007, 15:56

i was thinkin about using one of those "laser" measuring tapes.. i had a parallax ultrasonic sensor, which is probably not much different (although mine is only good to about 10 feet). i was thinkin about maybe adding a small servo to it, and mount a distance sensor on top, then it could sweep and it would be able to tell what distance at what angle (by using what pulse is sent to the servo).

my motors and motor controller dont arrive here till tomorrow, thats why its all just 'ideas" right now... when they get here, it will be time to start designing the PCB and putting it all together...

**dragons_fire** · - 13th April 2007, 00:38

so... i ordered some motors and a motor controller from robotshop.ca, and it gave me 3 shipping options... it could come on monday for $6, friday (3 days before) for $10 or thursday for $28.. i picked friday, so i would have them mto play with over the weekend.. well, guess what i just found in my mailbox (its thursday today for those of you who dont know) !!!

so im sitting here putting it all together and thinking.. i need a way to connect all these things together...
up until now, i have always used .10 headers for all my connections such as servos and sensors.. basically everything uses headers.. so my next question is:

does anyone know of any small 2pin and 3-pin connectors, that are smaller than .1 headers?? preferably with digikey part numbers if possible...

thanks again...
Danny

skimask · - 13th April 2007, 04:03

Originally Posted by dragons_fire

so im sitting here putting it all together and thinking.. i need a way to connect all these things together...up until now, i have always used .10 headers for all my connections such as servos and sensors.. basically everything uses headers.. so my next question is: does anyone know of any small 2pin and 3-pin connectors, that are smaller than .1 headers?? preferably with digikey part numbers if possible...

I would stick with the .1 headers for now, easy to put together, easy to tear apart if/when you make a mistake or a modification....but that's me, I'm crazy that way... As far as the smaller types go, flat flex cable maybe?
Have fun! Don't fry anything...at least anything that's not replaceable!

**dragons_fire** · - 15th April 2007, 06:16

SO i got my board designed now, and i used the .1 headers. i managed to fit everything on there, plus 18 I/O pins that can go to anoterh board on top. my issues that im having now, are that i dont think i can easily do thru-hole plating at home (i managed to fit everything on the board, using only 5 vias that i will need to solder a pin through), and i took a copy the design to staples for a copy, and they charged me 4 times as much because i wanted it dark, and its not good enough for me to use. now im looking into either getting my own laser printer, or trying out the inkjet transparencies. (i have about 8 injets lying around, they come free with almost everything now. within the next year or two, im sure we will see them at the bottom of cereal boxes!!!)

**mister_e** · - 15th April 2007, 18:07

transparencies film work great with inkjet printer. That's what i use here. Set your printer to the best resolution mode... yeah slower but better.

I tried laser printer in the past. i gave up, sometimes the toner don't do a nice and perfect job on 10-12mils traces.

Home made Thru-hole plating would be nice... but not a trivial thing. Sure there's some rivet kit available here and there... but it's a little bit expensive for what it worth. Better to outsource your PCB to some cheap PCB fabs.

Good luck!

skimask · - 15th April 2007, 18:11

Originally Posted by mister_e

transparencies film work great with inkjet printer. That's what i use here. Set your printer to the best resolution mode... yeah slower but better. I tried laser printer in the past. i gave up, sometimes the toner don't do a nice and perfect job on 10-12mils traces. Home made Thru-hole plating would be nice... but not a trivial thing. Sure there's some rivet kit available here and there... but it's a little bit expensive for what it worth. Better to outsource your PCB to some cheap PCB fabs. Good luck!

Inkjet? Really? I didn't think that worked at all! I tried the 'Press-n-Peel' method awhile back, used the good laser printer at OfficeMax, was really careful and all that. But it seemed like my problem was with the toner.
Does the ink actually dry on the transparency or do you have to be fairly careful with it (i.e. don't bend it, etc.)? How small are you able to get reliably on the traces and circles and the like?

**mister_e** · - 15th April 2007, 18:25

I've never had enough guts and patience to try the press and peel method. Yeah i like dealing with chemicals and black-rooms

Depending of your printer, you won't need to care about film handling. I'm a Canon printer fan. I use a IP4200. I print the film, wait 20-30 second (just for safety sake) then do the exposure job.

The ink stick on those film really well, you can bend them as you wish. no real problem. Just make sure you select the right film model for the right printer brand and you're in business.

I'd compare few film brands to see if there's any difference between them. Not really. I use those from staples.

PCBs brand make a difference. Here we can have those from C.I.F (circuit imprimé francais) or MGChemicals. By far, i prefer MGChemicals. Hassle free, work all the time.

**dragons_fire** · - 15th April 2007, 18:27

i tried a transparency on my injet on the last board i did, it worked amazingly well, nice and dark, with nice edges and all... my printer doesnt have rollers after the printing head, so i dont have to worry about it smudging, i just have to let it dry for 10 minutes after..
unfortunately, with the last board, my overhead got scratched and the board came out bad...

i think what i may try, is getting a laser printer, adn try ironing the toner onto regular (not-presensitized) boards. that way, i can use cheaper boards, and skip some of the chemicals..

**mister_e** · - 15th April 2007, 18:49

this method may have it's advantage for sure. My biggest concern, and also why it doesn't turn me on, is the precision of your layout alignment when doing a double sided PCB. With transparencies film it's just soooo simple to do.

You place your 2 films on a white sheet (or lightened table if you have any) align them perfectly, stick them together with tape on 3 edge (create a kind of pouch) and VOILA!

Place your film on your exposure gizmo, place your PCB the way you want without having to care about alignment, start neons, few minutes later it's done... on both side!

But yeah... you have to deal with exposure time, chemicals etc... but it's working really well. I did many successful prototype PCB using fine pitch SMD components, i can't confirm if the toner method would work as this well. But as long as it's working for you... life is good

If you scratch your film, or you use a fine tip ink pencil.. or simply print it again. Make sure you inspect them carefully first.

If you mess the toner transfer, what happen? is this easy to remove? What is the aprox cost of a toner-transfer sheet?

Films can be reuse again and again.

skimask · - 15th April 2007, 22:06

Originally Posted by mister_e

Place your film on your exposure gizmo, place your PCB the way you want without having to care about alignment, start neons, few minutes later it's done... on both side!

But yeah... you have to deal with exposure time, chemicals etc... but it's working really well. I did many successful prototype PCB using fine pitch SMD components, i can't confirm if the toner method would work as this well. But as long as it's working for you... life is good

If you mess the toner transfer, what happen? is this easy to remove? What is the aprox cost of a toner-transfer sheet?

Films can be reuse again and again.

I didn't realize you were using the pre-sensitized boards. I tried that too... used a couple of 15w flourescent bulbs for exposure (not even close to the right equipment to be sure), couldn't really get the hang of it. I suppose it was because of those bulbs I used.
Toner Transfer Sheets $ - they weren't cheap, cheaper than presensitized boards, but a guy still has to buy the blank copper. If you screw up the toner, sure you can take it off with a steel wool pad, but then you have to start over again, transfer it somehow, blah blah blah.
I'd really love to get my hands on one of those Protomat S62's for the house...only $25K with the options...pocket change! NOT!

**mister_e** · - 15th April 2007, 23:21

Yeah it's one of those machine some may want to have hanging on their bench

Maybe your tube haven't the right specs, were to far of your PCB, or your exposure time was not appropriate. You have to use special wave lenght tube (UV). regular Black-light tube (or lamp)have nothing to do with that. I usually pre-heat my tube before for 1-2 minutes.... once again for safety sake.

Once you have did few experiments, you know how much time your exposure time will be... it's almost the same everytime.

At least you will scrap 1 big PCB. if you're using 2-3 tube, this MUST take less than 2.5 minutes.

Start the exposure lamps and hide major part of your whole PCB with an opaque material
wait at least 1.5 minutes
move the opaque material to reduce the 'hidden from UV' PCB area every 5-10 seconds
develop the whole PCB and look where your PCB look the best.

At the bottom of this link, it's almost what i said... but in english

http://www.turbokeu.com/myprojects/pcb.htm
Enjoy and have fun with the pcb etching and... drilling job

EDIT: i heard some use now ultraviolet LEDs...

**dragons_fire** · - 16th April 2007, 15:54

the board is done now, and some of the stuff is mounted to it. im using the pic18lf6585, which is the low voltage one (but should work from 2 - 5.5V) and i have a 5V 5A regulator. when i connect the battery without the chip in its socket, everything works fine, as soon as i stick the chip in, the PIC and the Regulator heat up... i havent let the smoke out "yet" but they did heat up lots, and might not be any good anymore... i checked to see if i had Vss or Vdd backwards (so when i put the chip in, it would short out) but everything looks good.

if anyone has any ideas of why its doing that, please let me know.. heres a pic of the bottom of the board on my first attempt with the toner transfer method. the top didnt turn out as good, but there is only 3 traces on the top, and they werent affected.

my last question for everyone is: For PICs that have multiple Vss and Vdd's, do they all need to be connected (they are on this board), or are they connected internally?

**mister_e** · - 16th April 2007, 16:17

All VSS and VDD have to be connected.

From what i see on your picture, there's few potential traces short-circuit. Assuming there's no routing mistake and the original design worked, You should do a visual inspection first then use you Multimeter.
<img SRC="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1538&stc=1&d=117673623 8">

Seems to be caused by a lack of etching time or toner transfer... i can't tell.

The overall layout and routing looks good, the final results... so so. I try to avoid 90 degree routing, the etching process work better. It have also other benefits in high frequency.

I also try to avoid unconnected 'ground plane dedicated' copper islands.

Check if there's any polarised capacitor connected backward.

skimask · - 16th April 2007, 16:29

my last question for everyone is: For PICs that have multiple Vss and Vdd's, do they all need to be connected (they are on this board), or are they connected internally?

All Vss's must be connected together outside of the chip, same with Vdd.

And nice job on the PCB...really. The only things I was going to mention...mister_e already covered them...

As far as overheating, with the PIC out of the socket and power disconnected, if you put a meter between any Vss and Vdd, what do you get for a resistance reading? How about a Vf reading (normally seen as a continuity test on a meter when really it measures a diode's forward voltage)... Now try it with the PIC in the socket and power still disconnected?
Then hook up the meter to Vdd & Vss, turn it on volts, put the PIC in the socket, and plug in power just long enough to read the meter. Did the meter come up to system voltage? In other words...dead short somewhere on the board?

**dragons_fire** · - 16th April 2007, 17:53

Originally Posted by skimask

As far as overheating, with the PIC out of the socket and power disconnected, if you put a meter between any Vss and Vdd, what do you get for a resistance reading? How about a Vf reading (normally seen as a continuity test on a meter when really it measures a diode's forward voltage)... Now try it with the PIC in the socket and power still disconnected?
Then hook up the meter to Vdd & Vss, turn it on volts, put the PIC in the socket, and plug in power just long enough to read the meter. Did the meter come up to system voltage? In other words...dead short somewhere on the board?

1.036kohm across vdd and vss "with" and "without" the chip. i tried another regulator that isnt mounted to anything, and it comes back with the same reading.

5V without chip, 4.48V with chip

when i put my meter on the doide symbol (i have never used it before and dont know what it is), i get .324V without any power applied to the board (im assuming there isnt supposed to be)

skimask · - 16th April 2007, 18:09

Originally Posted by dragons_fire

1.036kohm across vdd and vss "with" and "without" the chip. i tried another regulator that isnt mounted to anything, and it comes back with the same reading.

1-ish Kohm... hmmmm...no dead shorts. Something is turned on by the PIC.

5V without chip, 4.48V with chip

Something's loading it down! Try disconnecting the motors? Try disconnecting and unsoldering stuff until you find the 'leak'. Maybe change your program a bit to make absolutely sure nothing is being driven for X seconds before something starts to happen.?.?

when i put my meter on the doide symbol (i have never used it before and dont know what it is), i get .324V without any power applied to the board (im assuming there isnt supposed to be)

Try this with the 'diode' symbol on the meter. Hook the meter up to a plain ol' diode, 1N4148, whatever you've got handy. Whatever the meter reads (within range of course) is what the forward voltage drop of the diode is and if the meter leads are connected correctly. The datasheets on the diode will tell you what the nominal values are. You can also use this function to correctly identify leads on a transistor.

**dragons_fire** · - 16th April 2007, 18:40

to be honest, when i said everything was soldered to the board, i really meant there a couple things soldered to the board... right now it has the regulator, the PIC, OSC, power switch, headers and i have a diode, resistor and cap on the MCLR pin.. they are connected exactly the way it says too in the march 2007 nuts and volts... mclr goes to the programmer, then there is a diode off of that, with a 4.7kohm resistor to dvv, and a 1uF cap to ground.

it gets so hot so quick, that i havent programmed anything into the pic yet, and because its a plcc, i cant really use my breadboard to try it...

im heading to work though, so if i get a chance, i may look at it some more to see if i can find any shorts on any pins, and make sure i have the mclr stuff on right..

skimask · - 16th April 2007, 19:41

I'll put money on the MCLR diode put in backwards.
Any takers for odds?

**mister_e** · - 16th April 2007, 21:41

i'll bet on at least one I/O short to GND (Vss) or short to another I/O. Try to set all unused I/O to input. But before, remove the PIC, measure impedance between ALL i/o and Vss, then Vdd.

Something suck juice here...

OR, a VSS is connected to VDD and so on... kind of routing mistake

If the MCLR pin was just put backward... the PIC would just act oddly... not suck as this juice.

How about the current measure?

**Darrel Taylor** · - 16th April 2007, 22:01

Originally Posted by skimask

I'll put money on the MCLR diode put in backwards.
Any takers for odds?

I'll take that bet.

It's got to be the Plethora of shorts that mister_e pointed out in the picture.
<br>

skimask · - 16th April 2007, 22:40

Originally Posted by Darrel Taylor

I'll take that bet.

It's got to be the Plethora of shorts that mister_e pointed out in the picture.
<br>

But the poster did say that the regulator/etc didn't get hot until he put the PIC in the socket. Doesn't really make sense to me either. Maybe the stress across a couple of pins on that socket are shorting out only when the chip is in.

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