Smokin'

Well took the stuff off of the solderless breadboard and put on the drive board. Somehow fried the 7805 regulator, not sure about the L293D chip yet. I need to make an independent power supply for times like this, preferably switchable from 5v to 3.3 for electronics and maybe even 12v for motors. Just a bit frustrated, can't find my solder wick and thinking I've tossed it, because it was in a bin outside that got rained in and everything in it was ruined and smelled funky.

The plan was to supply 7.2 volts to the 7805 to drop it down to 5v so as to not over voltage the motors, yes would have a prob with some heat. Keeping a steady amount of voltage to the motors would have been worth it. Now have to switch to something else I think to at least get it going. May use 4 AA cells to supply 4.8v to the motors till I figure out what smoked the 7805. Just called radio shack and they don't have any desoldering wick, major bummer. Was hoping to take Leo to the RBNO at the Generator tomorrow in working order. Time to grab a wet paper towel and desolder the hard way. At least enough to get my 4 AA holder back and the bad reg out of the board. If the reg was totally blown and not shorted, I'd just bypass it with jumpers, but it's in circuit and I don't want to blow the L293D.

Old problem that is new to me

Ok, I've gotten Leo to move some with his motors. Still working on the sensors and such. While working on the motors, one of the things that came to mind was the fact that any time his batteries are going dead, they have to be manually changed out. So if he's getting sluggish, then he has to be ripped open, partially gutted, sometime in the next few hours or even left that way for a day or three, then have freshly charged batteries shoved back in him, put back together and expected to perform just like he did before. Sounds violent and violating, I know so there is a much cleaner solution out there. There are seven batteries that have to be charged or changed out when he's go 'dead'. Yes this a problem for later, sense he can't even sense his environment yet, let alone navigate it. Suggestions are welcome.

I don't want Leo to be something I toy around with till I'm bored and then put on a shelf for who knows how long. Neither do I want him to be an electronic pet or pest. Like I said before, it's a problem for later. I believe that reaching any level of autonomy for a bot is a huge step. The roombas do their tasks, then return 'home', recharge and do their appointed task when their programming says to do so, so why shouldn't other bots do the same?

Got the motors running!!!

The L293D does weird things if you have both Enable pins high and nothing connected to the one of the Half H-bridge. Got all the wires connected in the right spots and low and behold, it works even the PWM is going well. That means that I get to take from the solderless breadboard to the permanent breadboard. I'm going to add a few filtering caps first though on the 7805, batteries and wires pick up lots of RF and especially from the cheap DC motors that make up the muscle part of Leo's drive unit. The next step will be to work on his bumper switches and then work on encoding the front idlers with hall effect sensors and rare earth magnets.


Progress Report:

1. Body Modifications 33% (still have the shell and to remount the shovel to make it a neck)
2. Drive Train 75% (Motors mounted, L293D working just needs to be finished)
3. Sensors 0% (2 IR receivers and 8 IR LEDs bought, 3 switches that need mounted, etc)
4. Circuits built 10%(L293D x2, 38MHz IR circuit, bumper circuit, etc.)
5. Programing 1% (motor test program works)

What needs to be bought:

1. 4 hall effect sensors $8
2. 4 0.25" rare earth magnets $10
3. Sonar Sensor $25
4. PIR sensor $10
5. 4 new motors $12
6. 1 servo <$10
7. 2 potentiometers <$5
8. Accelerometer $20
9. 2 ardiuno chips $14

Total = $110 +/- $3 plus $20 in S&H

Motor probs

Got the L293D hooked up, unsuccessfully. I can only get the right motor to turn in one direction. I don't know if I smoked the chip, will take the meter to it tomorrow. Both motors work fine and I have L293D hooked up as the spec sheet specifies. I probably need to add some 0.1uf caps to the 7805 regulator. Next time I find a bunch of them at a good price, I'm going to pick up a fistful of them. A bit worried that I smoked the chip and not in the good way you do ham and turkey. I can't seem to get the PWM on the arduino to work either, hopefully all these problems will be solved in the next few days. I'd like to add the bumper switches and probably an on/off switch so I don't have to chase him down.

For some reason, the right motor likes to stay in reverse.

Been busy and doing a lot of thinking

I've been looking into behavioral programming and it seems like the way to go. As humans we don't have set paths we take and certainly don't have encoders on our ankles to tell use how many steps or 'clicks' we take. Still need a tachometer of some sort, just like our brain keeps track of how many steps we take from point a to point b, even if we aren't conscious of the count. Yes there are some blind people who can use a form of PID to get around quite well, but we don't use it that much. Yes, I know...we depend on our sense of sight to get around. Well, we have lots of sensors to choose from such as IR ranging sensors, sonic ranging and internal mapping.

Here's been my thought process of late. We have an internal tachometer(the soles of our feet), we have an inertial guidance system(our middle ears), object detection(our eyes), and internal mapping(our brain). So following that bit of logic:

Human Bot

Feet Wheels, tracks, GEV
soles Hall Effect sensors and rare earth magnets on the wheels
Mid Ear Accelerometer (preferably 3 axis)
Eyes CMOS camera
Brain High Powered MCU with lots of Memory

If you go along with behavioral programming, then you are taking low level actions to make higher level actions. Combine that with some neural programming in the decision making and threshold processing you have. If you think about, if a bot has it's right bumper triggered, it backs up the path it came till it can make a decision on how to get around what ever made the collision..

Just some thoughts

Tonight's Work

Worked a bit more on Leo's body. All that is left after the glue dries is to do some trimming and the MCU shelf part is done. I've been trying to figure out what kind of hinges to use on the bumpers that won't stick. I had an epiphany while drinking a soda, reuse a soda can to make the hinges for the bumpers. It's quite fitting since Leo's body started off as a RC toy and has been upcycled to a bot body. I will be working on the front bumpers tomorrow afternoon.

My current dilemma is that I'm out of pins before I've begun really. I may put a pot or a resistor on the back IR distance sensor and make it digital, so I can have 2 analogs for the compass. Then I need to make the passive battery sensor only go low when it gets down to the point it needs to head 'home' to recharge. That would leave one digital pin unused, besides pins 0 and 1, which I already have plans for.


Progress Report:

Completed
Bot Body : Dozer Model(Modifications at 50%, Battery compartment and MCU shelf done)
MCU : AtMega328 Arduino

Incomplete
Sensors : 3 Bumper Sensors(3 Digital Pins)
5 IR Distance Sensors(5 Analog Pins)
Passive Battery Monitor(3 Digital Pins(75%,50%,Time to head home)
2 Encoders(2 Digital Pins)
Dual H : Still haven't ordered it(4 Digital Pins)
Compass: Still haven't decided which one (2 analog pins)

This is is what it started off looking like:

From Leo the Bot

I took off the bucket assembly :

From Leo the Bot

Then made an addition to the body:

From Leo the Bot

I am making the shelf the MCU sits on a bit wider, the batteries and the L293D will be under that, to keep heat and the RF they might throw off to a minumun and keep the the center of gravity low

I'd like to enclose the MCU part, once I get a compass in it. Then reuse the bucket assembly to make a neck of sorts for a PIR module and for sonar to sit on. I know by then I'll be out of I/O on the AtMega328, so will have to get another one and figure out how to make them communicate with each other. I need to pick up some solder wick, since I've yet to find what I did have.

The home depot trip

Got the wood needed for Leo's bod mods, got the ballast for the light in the kitchen though I think I'm going to take it back and get a new light though. Did some of the mods today. Really thinking of rethinking some of the mods. Don't want to run into weigt issues, or have too much time invested that I want to only use this bot body either.