June 25^th 2011

Today I did some rudimentary programming and circuit testing for the security mode of my rover. In the video you can see the various frequencies that the alarm will modulate within. It’s running with 5volts to keep the decibels down. The final version will be much louder in fact ear piercing I am sure. Circuit board is still being delayed because I can’t make up my mind on various details. A peek at the schematic you say…

here is my youtube link over at sicklabs http://www.youtube.com/watch?v=49IV2Mzf-C8

Performing some crude test tonight. Pan, tilt, Battery, and power management were completed.
The pan and tilt was a essential test to extract the “range of mobility”. The sensor deck needs to read analogous data, if that is that the correct word to use in this setting. And in doing so it must track without hitting the deck lid. I will attempt to move the base of the robot as the sensor deck approaches these outer limits.
Battery and power management works flawlessly, nothing went boom! That said and without out getting excessively technical (the ambient is working its subtle yet effective magic) I am pleased with the results so far.
Design update: engineering a circuit to monitor battery levels. Not critical for the robot but may become valuable when I inoculate it with code, bringing it to life…
http://www.youtube.com/user/SickLabs?feature=mhee
Ah almost forgot, check out my youtube page "Sick Labs "and see for yourself.

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Engineering a robot while on ambien.

This design, this curse, is finally starting to gain momentum. I am sourcing parts for my robot and given I know what features I want to implement, part sourcing is still tough. I am loosing my mind trying to stay awake and thumb through data sheets as fast as possible. All while it makes since, while the mind is fresh. You could spend a lot of cash on a particular part, or change design and it may end up costing less. But never over look the old “caught up in this chess match of, well this part is cheaper, but this part is better.” Often I find myself designing a circuit using cheap parts only to find out that the cheap parts need supporting parts that cost too much. This is daunting and could be a career all in it self.
Nevertheless I press on. I found a perfect IC to backbone my H-Bridge. The A4904 automotive full h bridge MOSFET driver turns out be be a complete unit for driving N-chan Mosfets and particularly N-chan Power Mosfet. I get all this for $4.27 in a 24 TSSOP package. I think I will ask for 8 samples from Allegro. So this may end up free of charge.
pointer for the nerds. On datasheets the words “automotive” typically means that the device runs on ~ 12 volts. This is valuable to know as it makes searching for mosfets and other IC so much easier.
Starting to doze out I want to mention some last details that are my notes:
Circuits that are complete or partial complete
Bat-led-cell 12V 2000ah
Switching power supply 3.3v core I
Switching power supply 5v core II
5v precession reference core III
2. H bridges
DAC
ADC
Wireless Bluetooth
4 GPS 128 satellite tracking
4 Servos
4 DC motors
1 chassis
1 pan & tilt
I/R sensor array
Sound detection
Gas sensor, monoxide, co2 etc.
Temperature
Humidity
Vibration
Acceleration
Time clock calendar
Television ir transceiver
Siren
display
camera