Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Just a clock...

Status
Not open for further replies.
Hi granddad,
since you are already considering to use I2C, why don't you use an I2C LED driver too?

I've used the 16 channel PCA9532 from NXP, very convenient and with lots of features.
 
Thanks ST , Had a look and will have to work out a circuit , Farnell only stock PCA9532 TSSOP ... but cheap ! < 2GBP
Edit , Found I have some SSOP break outs :)
 
Last edited:
Dont see why that wont work gramps, the only thing is that you might not be able to handle the display while receiving infra red commands so you'll get some flicker, but that wont be much of an issue.
 
Dr. Pepper:
that is precisely the beauty of the PCA9532.

Once that it has loaded the required data on the registers via I2C, the microcontroller is free to do whatever task it is required to do.
Even dimming and blinking is fully controlled by the PCA9532.
 
Just had a look at the 'sheet, yes thats a very usefull device.

On another note I did some more work on the Rds clock, well its actually a spectrum analyser, but its so slow it doesnt do a good job of that, but the clock is very accurate in radio mode as it decodes time from the Rds data carrier.
I have a few nixies/numitrons/thyratrons and some really old meters maybe I could do something Frankenstein or 'steampunk', or whatever buzzword it is these days.
(the music isnt rad1, its youtube non copywright stuff).

 
Last edited:
My clock project not off the desk yet but just out of curiosity I got one of the led clock kits from Banggood to see what was supplied...
mcu is a STC15F2K16S2,(TQFP) RTC is DS1302 with xtal and battery a couple of transistors, a buzzer , an ldr , NTC thermistor a couple of tactile switches, various caps and resistors, 3 8x8 led matrix. PCB plastic box parts and power connector.. ( mostly SMT parts )

Operational but no build instructions included , presumably you follow the screen print and component list. (document has a few translation or typo goofs ) “ avoid to resist digital tube affect beautiful “
ledclock.jpg
 
This is the 'BG' assembled clock , one or two Errrr ... moments. Instruction 'manual' as mentioned needs re-translating its pictures are c**P, no mention of some resistors / caps , Thermistor and LDR numbers swapped. But 8/10, good that spare R , C and Q 's provided . LED's don't have any drivers ,(a 7x4 font ) so I guess some PWM going on , so a line of 7 all ON changes the brightness a shade. Fun on a cold winters day. :D
dotclock2.jpg dotclock3.jpg
Edit: Its now 22:31 Clock, temperature and alarm work.. But something wrong with the time setting, does not go from 9:00 to 10:00 or above ? goes back to 0.00 then minutes will not advance correctly, will have to wait for tomorrow to set time before 10:00 am , rating now 5/10 ...
 
Last edited:
My matrix clock has taken shape, with 3 MAX7219 led drivers an RTC module and a PIC24FV32KA302 , the led matrix and driver were pre-assembled , so I mounted them on some strip board, driver circuit is bit banged with common Clock and Load with the data daisy chained in-out-in-out-in . I thought it was going to be easy sending an array 3x8 16 bit words . I worked out the code for each digit , stuffed the array , but result was not 12:34 , just a mess. some time before I got to this result . ( LEDs are RED ! ). Thought wrong again !
dotclock4.jpg

The clock is not being sent to the display yet this was a dotty test I need to work out best method for loading array from the BCD time .
----------------------------------------------------------------
The Banggood clock post #30, is running OK , but lots of complaints by builders to BG web site re, the time setting fault , emails to BG are taking an age to respond, if it is the mcu F/W , not sure how they are going to resolve it.
 
Very nice, grandad :cool:.

Admit it, you're having a ball, aren't you!?
 
The clock is not being sent to the display yet this was a dotty test I need to work out best method for loading array from the BCD time
Morning Gran,
Try a yellow filter in front of the LED's you should find it improves the contrast,

GGGranEric
 
Last edited:
Having spent some time and 'hair' coding my clock with red dot matrix, I decided to change to a square 8x8 white led , taken from the failed banggood kit, also got some smaller MAX7219 driver boards from 'hackspark' , so it would fit a 'hammond' plastic case.. was not considering the fallout of such a move :eek: my clock is now showing Egyptian hieroglyphics (12:31) so some more C time looming .... ( how long should projects last...? )
sqdotclk.jpg
 
... ( how long should projects last...? )
There are no known limits.

I've got some that are, literally, approaching two decades... :woot:.

You might ask "Why?". And I'd respond, "Because".
 
All else being equal (but, really, is it ever?), probably a pinout difference.

ak
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top