GUI v2

UPDATE 09/11/06  

 

It's finished! (almost). The Motor Board PCB arrives and I've soldered all components together. The final results looks awesome to me! Most beautiful that I've planed. There's some parts that I don't solder, because I need purchase a SMD rework station (all solders on this robot are made with a ordinary solder station). 

 

Two problems I only know after assembly:

 

• I've used RA4 pin of PIC18F452 for digital I/O, but unfortunately this pin is a open drain. Because that, I need to solder a pullup 10kΩ SMD resistor. Lesson: All the times, read the entire datasheet before use any device pin. 
• In my Eagle motor library, I don't provide horizontal restrictions. So, a little decouple capacitor stay above the motor, touch it, and make a bad contact between boards. Solution: remove it.

Well, even with all the issues (inverted connectors, capacitors with wrong package, pin without pullups) I think the whole project was a success. 

 

Now, the wireless part (NRF24L01+ transducer) waits to be soldered. It'll on the party next month. So, the whole project has been closed and I'll work on the software development, that I only write a very basic functions for test and maze solves.

 

 

 

 

 

 

 

 

There's a video of the test. And if someone needs more pictures or details, look at my Flickr page and my blog.

 

Thank's !!!

 

 

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UPDATE 09/09/13 

The first definitive PCB arrived from Batchpcb and are soldered!

 

 

 

 

 

 

I received the board at this weekend, it's the first definitive PCB of my GUI robot. It's your Motor Control PCB. Above are some images. Only left to solder the nRF24L01+ because I don't have a Hot Air Reflow Solder, and the Buzzer that I can't find.

 

Note that I've made a little mistake on p-Channel MOSFET SOT23 pinout (orange wire fix). But nothing too horrible (but in the GUI v2 design, I'll remember that...).

 

The new YouTube video contains a little test to PIC18LF452, to see if it's alive. The test was a successful.

 

Now, I expect that in the next week the Motor Board arrives too, so I'll complete the entire robot. 

 

 

My PCBs are shipped!  I'm very excitted to pick them up and solder everthing! But this update is about the schematics. I released the entire schematics of two boards and now I comment the most important parts. The full schematic are in the attachments.

 

 

The Micro Gear Motors and the H-Bridge circui. To save two I/O pins on MCU, I used a 74HCT04 for drive the directions commands. I have never used other combinations (like 11 and 00) in control logic. You can see on left down two Ball Caster. I put two because I need two orientations on holes. 

 

 

Motor Board - Battery and Interface with Controller Board

 

This is how the battery are attached to board. Nothing special. On the right are the female housing for up board connection. On of them is for reflectance sensors signals.

 

 

 

The LM2623 is a great Boost converter. Is very small (LLP or Mini SO-8 package) and use very tiny inductors. The output voltage is given by RF1 and RF2 voltage divisor by RF2=RF1/[(Vout/1.24)-1]. The frequency of PFM (Pulse Frequency Modulation) is setted by R18 andmay vary with input voltage (See page 6 of datasheet). In that design the frequency stay between 500KHz and 1MHz. The input and output capacitors are Tantalum capacitors, with X5R or X7R dieletric. I spect 85% of mean efficiency (over the voltage input range and current variation).

 

 

Motor Board - Reflectance Sensors

 

These are the QRE1113GR Reflectance sensors. I have to write their symbol and footprint, because I don't find them in any place. So, I spect that the design is correct, specially the footprint. There's a lot of stuff on this robot that I have created the Eagle library. If anyone needs, I put my personal library here.

 

 

 

 

Nothing special on MCU. Is a PIC18F452. Detail is the Breadboard Mini, for small prototype.

 

 

 

The Interface is given by a FD232RL, with self-power configuration. The 5V of USB don't power the robot, instead, charge the LiPo battery via MAX1555 circuit. I like MAX1811, because mre option like Low Batt indication, less charge time, but PCB space is a concern here.

After send the PCB for fabrication, I see a little mistake on this design. If you look this with Battery schematics, you see that only with the "ON/OFF" robot switch in "ON", the battery is charged. This was been corrected on next version.

 

 

 

For 3.3v devices i put a little LDO, because I don't need much power from this source.

 

 

 

 

The transceiver choosen is the nRF24L01+, from Nordic. That's design is the same of SparkFun nRF24L01+ breakout board. So, I hope that works. 

Certainly this part  will be the most dificult to solder, because the nRF package. I don't have a SMD rework air station. Only when I have one this part will be soldered.

 

 

Thank's.

 

 

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UPDATE 08/04/2009