You said you corrected your layout, but I still don't see bypass caps for your EEPROM or clock/calendar chip. One 10uF cap does not equal 100 0.1uF caps -- or even 10 -- for bypass purposes. More important than the bulk capacitance is how it's distributed. A sprinkling of many small low-ESR capacitors is way more effective for bypassing than one large cap, due to the reduced trace impedance at each IC's power pins.
Since the EEPROM and RTC Chips are low power and low speed devices, I thought I could "get away with it", since there is a lack of pcb space.
But if you insist, I will put them caps in.
Sapieha,
You have your point....
But I am still certain the regulator manufacturer will not recommend 1uF for input and output as the "typical recommended circuit" if it will be unstable.
I checked the schematic for the Propeller Demo Board and they also use 10uF caps for both regulators' output and a very small 0.1uF cap at the power jack.
ON: Manufacturer never know what You will use them to -->
And on all data sheets most values are always shown as "IDEAL conditions" - In You words "typical recommended circuit"
All concern on other conditions are Yours problem.
On: decoupling's capacitors "That are not same as Capacitor we talk on"
(decoupling capacitors have noit same functions as that BULK capacitor ve talk on)
EVERY IC need its one (In some times both) 10-100nF ---> that are little dependent on Frequencies that are RUN on PCB.
AS I said --- You need calculate total Current "IDEAL" consumption on Yours PCB to that add all Dynamic currents That some of Yours equipment need + ALL dynamic current consumption PROPELLER can give You.
AND You will know how big that Capacitor need be --> not forget to have at last same Capacitor on Voltage input (Little bigger if possible)
Since the EEPROM and RTC Chips are low power and low speed devices, I thought I could "get away with it", since there is a lack of pcb space.
But if you insist, I will put them caps in.
Sapieha,
You have your point.... But I am still certain the regulator manufacturer will not recommend 1uF for input and output as the "typical recommended circuit" if it will be unstable.
I checked the schematic for the Propeller Demo Board and they also use 10uF caps for both regulators' output and a very small 0.1uF cap at the power jack.
Now updated with one more bypass cap near the RTC.
No space to add a bypass cap for the EEPROM as I do not want to use turn pin IC holders due to costs. ( normal IC holders cannot be soldered at the front )
I think it will survive as I had many boards without bypass caps near the eeprom.
Also added a record button which you can hold down to record your voice via the mic into the micro-sd card. Spare IO header has been removed.
Did i tell you that there are 2 led headlamps in front which you can install IR leds?
These IR LEDs can tone down your TV volume if your kid sets the TV volume too high and the robot detects that the TV is too loud....
These IR LEDs can tone down your TV volume if your kid sets the TV volume too high and the robot detects that the TV is too loud....
I like this robot. It has a bad attitude.
Could you also program it to change to your favourite TV channel as well?
Another idea I saw once was an alarm clock and if you didn't turn it off within 10 seconds, it rolled off the table and rolled under the bed, and then you had to climb under the bed to turn it off and by then you were well and truly awake.
I wonder if you could program your robot to do this sort of thing?
Addit: That solar panel might not have a diode, so is there room on your board to add one? (if you don't use it, just install a wire link instead).
The solar diode is already there. See the first post image.
This robot can do anything your mind can think of.
For example, it can start recording whenever it hears loud sounds so you will know what the maid was doing while you were at work.
I am still thinking of adding a compass, temperature sensor and battery level detector but it looks like there is no more space.
If it has a temperature sensor, it can switch off your air conditioner when your room is too cold and switch it back on when it is getting too hot so you can sleep soundly.
Comments
You said you corrected your layout, but I still don't see bypass caps for your EEPROM or clock/calendar chip. One 10uF cap does not equal 100 0.1uF caps -- or even 10 -- for bypass purposes. More important than the bulk capacitance is how it's distributed. A sprinkling of many small low-ESR capacitors is way more effective for bypassing than one large cap, due to the reduced trace impedance at each IC's power pins.
-Phil
Since the EEPROM and RTC Chips are low power and low speed devices, I thought I could "get away with it", since there is a lack of pcb space.
But if you insist, I will put them caps in.
Sapieha,
You have your point....
But I am still certain the regulator manufacturer will not recommend 1uF for input and output as the "typical recommended circuit" if it will be unstable.
I checked the schematic for the Propeller Demo Board and they also use 10uF caps for both regulators' output and a very small 0.1uF cap at the power jack.
ON: Manufacturer never know what You will use them to -->
And on all data sheets most values are always shown as "IDEAL conditions" - In You words "typical recommended circuit"
All concern on other conditions are Yours problem.
On: decoupling's capacitors "That are not same as Capacitor we talk on"
(decoupling capacitors have noit same functions as that BULK capacitor ve talk on)
EVERY IC need its one (In some times both) 10-100nF ---> that are little dependent on Frequencies that are RUN on PCB.
AS I said --- You need calculate total Current "IDEAL" consumption on Yours PCB to that add all Dynamic currents That some of Yours equipment need + ALL dynamic current consumption PROPELLER can give You.
AND You will know how big that Capacitor need be --> not forget to have at last same Capacitor on Voltage input (Little bigger if possible)
That was all I have to say on this topic.
No space to add a bypass cap for the EEPROM as I do not want to use turn pin IC holders due to costs. ( normal IC holders cannot be soldered at the front )
I think it will survive as I had many boards without bypass caps near the eeprom.
Also added a record button which you can hold down to record your voice via the mic into the micro-sd card. Spare IO header has been removed.
Did i tell you that there are 2 led headlamps in front which you can install IR leds?
These IR LEDs can tone down your TV volume if your kid sets the TV volume too high and the robot detects that the TV is too loud....
I like this robot. It has a bad attitude.
Could you also program it to change to your favourite TV channel as well?
Another idea I saw once was an alarm clock and if you didn't turn it off within 10 seconds, it rolled off the table and rolled under the bed, and then you had to climb under the bed to turn it off and by then you were well and truly awake.
I wonder if you could program your robot to do this sort of thing?
Addit: That solar panel might not have a diode, so is there room on your board to add one? (if you don't use it, just install a wire link instead).
The solar diode is already there. See the first post image.
This robot can do anything your mind can think of.
For example, it can start recording whenever it hears loud sounds so you will know what the maid was doing while you were at work.
I am still thinking of adding a compass, temperature sensor and battery level detector but it looks like there is no more space.
If it has a temperature sensor, it can switch off your air conditioner when your room is too cold and switch it back on when it is getting too hot so you can sleep soundly.
The latest design has now been updated in the first post.
Looks like I have run out of PCB real estate.
If there are no more suggestions, I will send it for manufacturing in 1 weeks time.