Topic: Hardware

Still playing with hardware... I think I'm actually learning. I've figured out how to use transistors, h-bridges, shift registers, and I can build basic circuits. I don't have an o-scope so I have trouble knowing when to add caps in certain places, but I'm getting there.

I'm getting pretty good with eagle, and I've had a few boards made at batchpcb, they have all worked as designed, which is great. I'm currently trying how to figure out how to put components on both sides of the board.

I'm still using arduino, but I have also started using C to program AVRs, I'm writing directly to registers in a lot of places. As soon as I can figure out the sleep functions, and get a little better with the timers for pwm, or prescaled timers I'll be moving to assembler.

I've breadboarded some neat multiplexed arrays, and recently charlieplexed arrays. Now I'm trying to make a nice 8x7 array out of smt leds. I think I'm going to use an atmega 168(or a 169) to drive the array, and I want the driver circuit to be on the backside of the array... all smt, nice and flat.

smt components are so damn cheap.. I can get 100 smt leds for $6, a cpu for well under $2. Resistors and caps are just pennies. I'm trying to put together a basic set up for making my own boards as well for rapid prototyping. They wont be as nice as the ones from batchpcb, but they will cost about the same, and I wont have to wait 4-6 weeks for them.

If I want to reproduce or improve a design, the cycle will be shorter, and my final designs can go out to a real fab house. For example the charlieplexed array I've come up with will evolve to be a 3X18 array(closest I can get to 56, maybe I'll make it wider, maybe I'll make it 5X18, which will be a 10x9 charliplex, yeah I like that more), and add an eeprom for memory, where I can save charset data, maybe a few buttons to make it easily programmable by user, a 3v coin cell, and bam, I have a really cool standalone, programmable, marquis for maybe $10 in retail components, probably half that if I kit it. dorky belt buckles are even better if they are home made ;)

The software part will be fun, the hardware part is still a bit challenging for me... but thats why I like it. Hobby a-la nerd.

Well arduino has got me hooked. I've learned a lot from the arduino, and I'm making my own circuits now. That said my circuits usually run off an arduino, boarduino, wee, arduino mini pro etc... all arduino clones. The thing is arduino has gotten me a lot closer to the hardware.

So I have an iscp programmer(a USBTiny) and all the atmel chips support icsp so I just wired up a few ad-hoc boards. I made a dual icsp programming board, for both 8 and 20 pin DIP packages of attiny chips(the attiny13, attiny45, attiny85, attiny2313 etc, etc) I also made a quick v5v powersupply for my breadboard, it takes anywhere from 7-18V, has caps to filter out noise, and even reverse current protection. If I need to flash an atmega16x(28 pin), I can just use an arduino board, I also have a kit from datapro that holds an atmega32(40 pin)

I'm learning how to program these in C and C++. Suprisingly I've learned a lot more bitmath too... its just so much easier to do stuff on a chip this way. I really want to learn how to use the low power functions and I can make really cheap circuits when I can get this close to the chip. Who knows maybe assembler is next?

I got a prototype zifduino, its an arduino, but with a zif socket on it. This makes it ideal for prototyping, and them simply popping the chip out, and putting it in a more permanent fixture once the software is complete. It will also be good for flashing lots of chips, verifying them, then using them. It is a prototype, but I think its fun helping the designer and providing feedback. I should have the next version of the zifduino as well, since there will probably be a few cycles till the boards is complete.

Eventually I will make some of my own boards, I hoping to learn a little in this process as well.

I got a pololu chasis, tamiya gearboxes, a pololu dual serial motor controller... and the damned controller does not work... so as an experiment I picked up a boarduino, and retested everything... still no workie... so I'm sending back the controller...

I refuse to give up however so I plugged an L293DNE into the board next to the boarduino... it works, but only with a motor supply current of 6V(4xAA batteries) I tried 3V(2xAA) and it was a no go. The motors are rated at 1.5-3v... hrm.... I've got some questions to ask. The 293 runs at 4.5-6v... and I have it on the 5v vcc from the boarduino(thats the reference voltage for the chip)... I'm not sure it it will push 3v through as 2x1.5 motors though... does the 6v battery pack for the motors get its voltage split? If so I'm great... if not its gonna melt these motors... but hey it works!

here is a pic and link to the gallery with a few pics of my lame bot.

I've been playing with an arduino, partly cause I"m bored, partly because I want to learn more about microcontrollers. The low level stuff. Arduino has a library that can control an LCD directly... no challange in using a pre-writen library... and it uses a whole lotta pins... so I picked up a K107 serial controller from Wulfden the firmware was actually writen by Peter H. Anderson he uses to proceeds to help fund his classes. It came as a kit, so I had to solder, and all that... pretty simple really.

Not challenging to use but I though it was worth a picture. My arduino decimilia and the k107 with a blue/white backlit LCD... aint she pretty.