Question about relays to be used with MICROCONTROLLERS

[reaver26]

reaver, why don't you use a schematic capture software... dami naman dyan libre... express pcb would be ok.


ok naman yung schematic mo... but i would recommend this one:




in this case, current for the LED will be pulled from the supply 5V supply rail instead from the MCU pin. note that most MCU I/Os can only source up to 25mA. yung sa schematic mo, ok naman... yun. i am just saying this one is better.

R3 should be replaced if in case you'd use a higher voltage coil rating for the relay.

clarification lang po... yung GROUND sa dulo ng R2 is it the same with the VDD?
=D

[rdpzycho]

Vdd ng alin? commonly, Vdd refers to the positive supply of a FET based circuit and Vcc refers to the positive of a BJT based circuit. in this case, Vdd would be at the cathode of the diode.

[reaver26]

Vdd ng alin? commonly, Vdd refers to the positive supply of a FET based circuit and Vcc refers to the positive of a BJT based circuit. in this case, Vdd would be at the cathode of the diode.

mali po VSS pla...

clarrification again. sorry po if makulit ng iingat lang po ako.....

[marcelino]

you did say that your relay requires 5V on its coil part, right?

hopefully this will make things clearer...

[reaver26]

@ sir marcelino tnx sir very clear presentation good thing meron ako board setup using pic16484A

gagawin ko na po ang RELAY setup ko mmya. tnx po ulit... update lang po ako if my further questions regarding electronic circuits...


remaining problem na lang sa MCU KEYPAD code.

OT na po ito:

how to get the the encoded key in sequence 1-6 and send that 6 sequenced key  thru uart (db9).

the sequence key is indicated by 6LEDS. "#" will be the sending button/key

example:

* 437528 #
" * " = initiate the start of the input of the key

if that key match the one on the other side of the uart it will respond a confirmation indicated by a GREEN LED
if that key doesn't match the one on the other side of the uart i will respond an error indicated by a RED LED

[reaver26]

nagkamali po ako hehehe pinag sama ko ang VDD at VSS kya di mag work

[RaffT]

dapat din lagyan decvoupling CAP NEAR the relay... 220uF + 100nF is OK....

[marcelino]

curious...!

i am using that circuit myself....
1. are you sure that 5V ang coil rating ng relay mo?
2. tama ba ang orientation ng 2n2222?

try to connect the input to a 5V, the 2n2222 should close.

ok lang yang 5k mo.
at kahit 1/4W nga lang.

[reaver26]

you did say that your relay requires 5V on its coil part, right?

hopefully this will make things clearer...

pwed po ba na yung input ko from MCU would be also my VDD? if pwed lang po... wala lang transistor kung ganun. di ko kasi alam saan ikakabit ang VDD  nya... input from RA0 will to ground of the TRANSISTOR to complete the flow.. yung VDD sa relay di ko alam saan ikakabit sa MCU ko....

[reaver26]

curious...!

i am using that circuit myself....
1. are you sure that 5V ang coil rating ng relay mo?
2. tama ba ang orientation ng 2n2222?

try to connect the input to a 5V, the 2n2222 should close.

ok lang yang 5k mo.
at kahit 1/4W nga lang.

DLSU1 U
5VDC 0.15w

5A/100A
3A/120A
250V~


yan po nakalagay sa Relay ko...

it has 4 LEGS.

[marcelino]

pwed po ba na yung input ko from MCU would be also my VDD? if pwed lang po... wala lang transistor kung ganun. di ko kasi alam saan ikakabit ang VDD  nya... input from RA0 will to ground of the TRANSISTOR to complete the flow.. yung VDD sa relay di ko alam saan ikakabit sa MCU ko....

di dapat kasi as I have mentioned, 25mA lang ang kayang i source ng PINS ng MCU. most 5V relay requires around 200mA.

VDD = 5V.

saan ba galing ang 5V supply mo?

verified mo na ba sa datasheet ang pins ng 2n2222A?

[reaver26]

di dapat kasi as I have mentioned, 25mA lang ang kayang i source ng PINS ng MCU. most 5V relay requires around 200mA.

VDD = 5V.

saan ba galing ang 5V supply mo?

verified mo na ba sa datasheet ang pins ng 2n2222A?

5V supply galing po sa RA0 when initated po ng MCU ko. kya ganun ang nagawa ko na flow kasi

RA0 (ON(5v)/OFF(Ov) ==>RELAY trigger(5v) ====
  ^                                                             V
  ||==================================

parang ganyan po ang flow nya... 

[marcelino]

try to remove first your mcu... yung switching circuit na muna.

giving 5V to R1 should energize your relay.

so this means that giving a high level signal will turn on you relay.

dito nalang tayo usap, medyo busy kasi at para makapagcomment din yung mga master natin.

[reaver26]

try to remove first your mcu... yung switching circuit na muna.

giving 5V to R1 should energize your relay.

so this means that giving a high level signal will turn on you relay.

dito nalang tayo usap, medyo busy kasi at para makapagcomment din yung mga master natin.

i tried to energized it on R1 pero ang problem... saan ko ilalagay ang negative ko? dun sa emitter ng transistor?

ano ilalagay ko dun sa VDD? sa dulo ng D1?

[reaver26]

sir marcelino see my breadboard setup. i tried to power it up using 5vDC output

hindi naga energize ang RELAY
nearly 10volts... nag energize na sya.

hindi kasi accurate ang voltage ng multiple converter ko.

3v = 5.9v ( LED OFF, ENERGIZE OFF )
4.5v = 7.6v ( LED ON, ENERGIZED OFF )
6v = 9.4v ( LED ON, ENERGIZED ON )

[marcelino]

medyo naguguluhan ako ng image mo i cant see a connection to the middle pin of transistor (base). also the emitter part seems to be connected to the relay part...
eto po yung pin config. (kaya nga pinapaverify ko sayo yung pins ng 2n2222 kanina.)



just to make it much clearer to you, do this experiment...

when you hit the switch, it basically connects the R1 to 5V rail. then turning ON Q1. when the switch is released, the 10k resistor will pull the based voltage of Q1 to gnd or 0 level - turning it off. If Q1 is turned ON (like shorted) current will flow through the coil of relay, hence energized. and if Q1 if ON, current will also flow through LED limited by 390 resistor.

it seems your background to schematic reading (as well as data sheet reading) is not yet that into your system. nweis, ok lang yan... ganyan din ako nung magsimula.

[reaver26]

medyo naguguluhan ako ng image mo i cant see a connection to the middle pin of transistor (base). also the emitter part seems to be connected to the relay part...
eto po yung pin config. (kaya nga pinapaverify ko sayo yung pins ng 2n2222 kanina.)



just to make it much clearer to you, do this experiment...

when you hit the switch, it basically connects the R1 to 5V rail. then turning ON Q1. when the switch is released, the 10k resistor will pull the based voltage of Q1 to gnd or 0 level - turning it off. If Q1 is turned ON (like shorted) current will flow through the coil of relay, hence energized. and if Q1 if ON, current will also flow through LED limited by 390 resistor.

it seems your background to schematic reading (as well as data sheet reading) is not yet that into your system. nweis, ok lang yan... ganyan din ako nung magsimula.

ITS WORKING NA PO BALIKTAD ANG TRANSISTOR KO..... THANK YOU VERY MUCH ok na ang RELAY CIRCUIT NAMIN... thank you for your help............... i owe you BIG TIME..........

[marcelino]

ITS WORKING NA PO BALIKTAD ANG TRANSISTOR KO..... THANK YOU VERY MUCH ok na ang RELAY CIRCUIT NAMIN... thank you for your help............... i owe you BIG TIME..........

good luck on that!

[reaver26]

HELP URGENT: sir marcelino...... wala na available 5vdc/220vac

6vdc/220vac na lang po...


paano po ito.... 5vdc lang output ng MCU ko....

[rdpzycho]

ano ang source nung MCU mo bago maging 5V? 'di mo naman directly ipo-power ng MCU 'yung relay, pang-drive lang 'yung 5V.