how would one go about connecting a Velleman K8023 with micro controller ?
Use NPN transistors to create the open collector, the K8023 can we switched with.
To make many of these connections, you would normally use transistor arrays like the ULN2803A that is used on the K8055 for example. They are 8-channel darlington transistor arrays that are compatible with logic input and provide open collector output. Look at the K8055 schematics to see how they are used.
Use NPN transistors to create the open collector, the K8023 can we switched with.
To make many of these connections, you would normally use transistor arrays like the ULN2803A that is used on the K8055 for example. They are 8-channel darlington transistor arrays that are compatible with logic input and provide open collector output. Look at the K8055 schematics to see how they are used.[/quote]
Im sorry I’m not the best with this could you tell more please?
Sure, but where do you want me to start? Do you know what “open collector” means?
lol yes( for the most part)
the problem is when i ground the two device’s, the led on K8023R turns off and unresponsive … im thinking maybe they have to be on the same power source ? ( witch is at the K8023R 250ft away)
as for the pnp transistor
The collector is connected to the channel that you want to turn on on the K8023S
The base is connected to the channel that you have turned on on the micro controller
The Emitter is connecte ground to the K8023S and the micro controller
have i got this part rite?
lol yes( for the most part)[/quote]
I have learned to not take these things for granted any more and just ask.
I said NPN transistor!
[quote]The collector is connected to the channel that you want to turn on on the K8023S
The base is connected to the channel that you have turned on on the micro controller
The Emitter is connecte ground to the K8023S and the micro controller
have i got this part rite?[/quote]
You might want to have a current limiter in there like so:
For your average “variety pack” NPN transistor, like a 2N222A or 2N4101 and a microcontroller supply voltage of +5V, R1 of 1K5 would work. That limits the base-emitter current to 3.3 mA, which is more than enough.
The ULN2803 is an 18 pin IC containing a transistor array. It has 8 inputs and 8 outputs. Each input/output pair is a Darlington transistor with all the current limiters and protective diodes built in. Simply connect pins 1…8 to the microcontroller outputs, pin 9 to ground, and ready are 8 open collector outputs on pins 18…11 to be connected to your K8023. No other components needed. They usually cost less than a dollar.
the problem is when i ground the two device’s( The Velleman K8023s with micro controller) , the led on K8023R turns off and unresponsive …
what do you think?
[quote=“shaneb24”]the problem is when i ground the two device’s( The Velleman K8023s with micro controller) , the led on K8023R turns off and unresponsive …
what do you think?[/quote]
I think you somehow managed to short circuit GND of the K8023R with GND2 of the K8023S. What is the resistance between K8023R-GND and K8023S-COM?
i got it to work but what really confused me was that the micro controller to K8023 did not share a common ground
Neither do the K8023R and K8023S share a common ground. GND is not directly connected to GND2.
Look at pages 15 and 16 of the K8023 manual vellemanusa.com/downloads/0/ … _k8023.pdf
The two VTX wires are used for two things, providing power for the K8023S and transmitting information. The K8023S transmits a serial signal over them by altering its power consumption. Together with R15, the K8023S itself builds a voltage divider. The voltage on VTX is 10V. If the K8023S draws less than 24 mA, then the voltage at the base of transistor T1 will be less than 0.5 V. Output pin RA1 on the K8023S can make transistor T2 to draw an extra 50 mA or so, which puts the voltage at the base of T1 over 1.0 V. And that’s how the K8023S turns T1 on/off.