k8055

Kits PC Related Projects
1

This question is for the velleman technical team

I have brought a velleman k8055 ready made project board and have only looked at it for one day and allready it is up and running and i love it!
with little programming knowledge i already know i will be able to program it easilly. the vistas .net version of the test program compiled and run on my old laptop running xp (how is that for vista wow!)

any way my questions are

  1. the circuit diagram shows that an external power supply can be connected (+ to the clamp input and - to ground)

my questions on the kit are :-
do any links on the pcb need to be broken if using an external psu or is this allready taken care of in the circuitry(with no damage to the usb port on my pc)

what reasons do you need an external psu. i.e. with more than one k8055 kit connected to the pc drawing too much current and damaging the usb port and/or kit (current drawn is greater than the specified usb 1.1 interface standard)

  1. I plan to connect a stepper motor kit to the k8055 (1 digital output for direction and one digital output for pulse) The instruction manual states that the ground plane on the k8055 is connected to the ground of the pc (via the usb).

where on the k8055 would be the best place to common the ground from the stepper motor kit, and what isolation would you recomend ( if any) to stop the transfer of any noise spikes from the stepper motor kit through the k8055 and into the p.c. (i dont want the p.c. to crash)

  1. Why dont you sell the preprogrammed pic 16c745 chips as a stand alone item for any body that wishes to make a compact board for their projects. it would make buisness sense. At least you sell some thing rather than force developers/hobbyists to look else where for stand alone open source pic usb bit whacker chips with open source code. (I hope you did’nt think all hobyists are dumb and dont check the other options on the net).

javascript:emoticon(’:shock:’)
Shocked

The price for the chip would have to be some where between the kit price and the pic unprogrammed price (with possibly a price reduction voucher for pre existing owners of the k8055 experiment boards).
javascript:emoticon(’:idea:’)
Idea

Saying that you will not consider even looking at
the option of selling the stand alone preprogrammed pic chips unless in a experiment board is being greedy and will turn customers off your product (your loss )
javascript:emoticon(’:roll:’) Rolling Eyes

2

Hereby a brief answer to your questions:

[quote]1) the circuit diagram shows that an external power supply can be connected (+ to the clamp input and - to ground)

my questions on the kit are :-
do any links on the pcb need to be broken if using an external psu or is this allready taken care of in the circuitry(with no damage to the usb port on my pc)
[/quote]

As the K8055 is equipped with open collector outputs (check this forum for explanation what open collector outputs are) you need an external supply to drive the equipment that you connect to your K8055. The K8055 does not source a voltage, it acts as a PC controlled switch.

[quote]) I plan to connect a stepper motor kit to the k8055 (1 digital output for direction and one digital output for pulse) The instruction manual states that the ground plane on the k8055 is connected to the ground of the pc (via the usb).

where on the k8055 would be the best place to common the ground from the stepper motor kit, and what isolation would you recomend ( if any) to stop the transfer of any noise spikes from the stepper motor kit through the k8055 and into the p.c. (i dont want the p.c. to crash)
[/quote]

We do not know the specs of this stepper motor kit. If it is well designed, it should not transfer spikes to the K8055. Can it be controlled with open collector outputs ?

[quote]3) Why dont you sell the preprogrammed pic 16c745 chips as a stand alone item for any body that wishes to make a compact board for their projects. it would make buisness sense. At least you sell some thing rather than force developers/hobbyists to look else where for stand alone open source pic usb bit whacker chips with open source code. (I hope you did’nt think all hobyists are dumb and dont check the other options on the net).
[/quote]

This is a marketing decision. Discussing marketing decisions is beyond the goals of this forum.