I am! Now i am working on a
I am! Now i am working on a laser tag project though, using picaxe.
http://www.computerhope.com/issues/ch000352.htm said:
“Discharge current: The recommended discharge current of the NiMH is considerably less than that of the NICAD. For best results, manufacturers recommend a load current of 0.2C to 0.5C (one-fifth to one-half of the rated capacity, see 3.1 C-Rate). This shortcoming may not be critical if the required load current is low. For applications requiring high power or a pulsed load, such as on GSM digital cellular phones, portable transceivers and power tools, the more rugged NICAD is the recommended choice.”
http://en.wikipedia.org/wiki/Nickel_metal_hydride_battery said:
“Common AA cells (penlight-size) NiMH batteries have nominal charge capacities (C) ranging from 1100 mA·h to 2900 mA·h at 1.2 V, usually measured at a discharge rate of 0.2×C per hour.”
But this is usually. To be certain check your battery datasheet or something like that.
my cells are NiCd… so i am
my cells are NiCd… so i am coinfident that them can deliver enought current to operate small motors
Damn, why didn’t anyone told
Damn, why didn’t anyone told me that like… 6 months ago.
But yeah, robot idea is good. Small robots are always good. Some day i will make one for myself too. But smaller.
i was wondering about
i was wondering about security issues
what appens if i am out of home for a week and the critter fails to disengage then recharger plug after the full charge?
have I to expect dangerous flames? 
I read somewhere that a Charging current <= 1/10 C can be provided for days without hazard…
but if i want a higher charge current i have to think to this problem
Maxim (and a number of other
Maxim (and a number of other chip manufacturers) have battery charger ICs that monitor battery charge level and change charging based on what they detect, whether voltage, temperature, or current change. These would drop to a trickle rate once a battery has reached full charge.
You can also hook it up so
You can also hook it up so when it receives a charge to just shy of max it trips a relay that makes the motors got backward and away from the charger. The code should see the battery is full enough and ignore the charger.
the problem is this:i can
the problem is this:
i can not risk a flameout in ny house if somethink go wrong
this is the idea:
1) bot detect electrical docking
2) bot start to count time. after a certain amount of time it know that the charging in complete and backward motor at will to detach itsel from charging bay
3) charging station is picaxe or maxim( thx to robologist ) controlled and when it detect battery full , it stop current
so we have double security mechanism and bot is not overloaded with electronics
Have a look at this robots
Have a look at this robots circuit. It uses PD1 to detect the 5v charger current and PD0 switches the current on and off through a couple of transistors. It charges for 50seconds then stops and uses the PB0 ADC to check the battery voltage.
No need for a special charger IC if you can spare some program memory to take care of it.
PNA4602 modulated ir
PNA4602 modulated ir sensor require at least 3.3 v to operate
this means that 3.3v / 3 cells = 1.1 v
i am unsure is a NiCd cell can be considered totally depleted at 1.1 v
i fear lazy effect…
i can:
1) switch to a 4 cells setup (bigger robot)
2) use straight IR led light (not modulated)
3) keep this setup and send the bot to recharge when battery are 1.1v (insufficient discharge=lazy effect?)
1) excluded2) tested: it do
1) excluded
2) tested: it do not works
3) ok
this is the schematic of the
this is the schematic of the battery charger
it’s picaxe controlled
it’s able to detect if battery is atteched and sense battery full condition via ADC sensing (I hope)
delta peak or simple threshold
i am a little in troublei
i am a little in trouble
i have to develop a subsystem able to detect anvironment audio pressure level
if i clap hand it have to recognize the round and react
it have to be able to know if the environment is silent or not
i have done a simple test connecting scrapped mobile mic with oscilloscope
but the signal is very very very low
amplyfing it coul be tricky for me…
is there another simple solution?
thankyou
subsystems
INPUT:
-2 Contact feelers (hands)
- environament LDR sensor
- environment sound pressure sensor (ears)
- directional modulated ir rensor to head to the batt charger (smell)
OUTPUT:
-2 geared motors (legs)
-2 red led (eyes)
- pezo buzzer for voise (voice)
… i know, there is not a front sensor able to range obstacles :</p>
I don’t know much about this
I don’t know much about this but doing a few quick searches:
http://www.instructables.com/id/Make-a-Simple-Audio-Amplifier/ this is probably much more than you need.
There is a chip the LM386 and other similar ones here is a data sheet:
http://www.national.com/ds/LM/LM386.pdf
Maybe something to look at. This is probably stupidly unhelpful as I don’t really know much about amplifiers.
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posted new video
the audio level recognition works fine
it will be able to respond to sound pressure levels of the enviroment as clapping hand or the silence of the night and so on
it will behave according to those stimuli…
LDR provide anvironamental light level…
in a dark and silend environment it will fall asleep and snore…a buzzer will provide the voice
i am able to control the volume of the buzzer thanks to extra circuitry
it’s a dual op amp
one half conftrol volemue of the buzzer
the other half amplify the mic for sound recognition
this is the schematic
AUDIO IN + AUDIO OUT:
how about these
how about these ?
http://www.schursastrophotography.com/robotics/dockinglogicdocking.html
http://www.schursastrophotography.com/robotics/dockinglogiccontacts.html
hahaahah GREAT link!!it’s
hahaahah GREAT link!!
it’s exactly what i am doing now with my critter project
i will read that site carefully
many THANX!!
i got a problem with AUDIO
i got a problem with AUDIO IN circuit (chack schematics)
it works perfectly when mortors are still… but when motors go on it’s a mess!
obviusly the hi-gain op-amp amplify all the noise from the motors and it saturate.
HOW TO MAKE IT IMMUNE TO VCC NOISE?
oh boy, sensitive amp
I don’t suppose you could separate power supplies on this little critter?
Maybe you should not try to suppress motor noise specifically. Try to block ALL frequencies, except for a very few that you DO want to “hear”. Like the frequencies that are carred by an (old fashioned) telephone network. Dunno, maybe from 1000 to 8000 Hz?
Some other bard will have to explain which capacitors you would need for that.