Saturday, October 24, 2009

kit velleman k8055 (or vm110) - coupling with rc servo

step 1:
K8055 velleman card working! :)
using K8055_full_demo_app-

step 2:
control rc servos through the k8055 using the following 0-5vdc to 1-2 ms pulse over 16 ms cycles. (ideally 19ms but hey nothing s perfect)

components calculated from:

note a red Led has been inserted to visualise power in serie with a 390 ohm resistor; final dual circuit impedance is close to 420 ohm due to the 2x 1Kohm variable resistors etc..., I also added an electrolytic condenser of 470 µF for power filtering.

Dual 0-5 vdc to RC servo signal converter

in bi-servo configuration: with a 1A 5vdc alimentation not delivering enough power, peak power consumtion by 1 servo induces the move of the other servo (the well known low battery power effect). Using a battery with its RC regulator showed much decreased interferences. Hence it would be good to have an alimentation of 5vdc 5A minimum (stable alimentation can be achieved easily using several parallel power regulators 7805 with a common cooler).

(adaptation from

edit as asked on comment:
top view (from component parts)

little help for those that want to build the circuit on a pre-drilled plastic support. don t forget to connect legs 4 and 8 of the 555.
watch out, all crossings should not be connected, check on the sheme above to make sure. The connection to the servo is depending on your device's plug, it needs signal, +5vdc and gnd.
good luck

Wednesday, October 21, 2009

how to fix a Krups balance that has a broken screen?

What, no numbers printed on the screen of the balance!!! oooooooooooppps let s fix it!

What i did: re-melt the connections of that little µprocessor (a lot!!) being carefull not to make shortcuts with some Sn-Pb melted metal. in fact i had discovered that pushing it made the creen parts work again erratically, that was a bit clue!

Still a few problems... lets melt the other side of the µprocessor too

It works!

the cause of the problem : the pad pushing on the µcontroller that got misconnected due to stress. i removed a bit of plastic... problem solved.

Saturday, October 17, 2009

Radiation risk OR Max danger in the office!

small do-it-yourself for office use:

a rough copy of ILL Neutron shutter danger panels.
Orange: Risk of irradiation, Max is relax, but ready to bug;
Red: danger of irradiation or Do not bug Max now.

Tuesday, October 13, 2009

Salon eurobio 2009

just a bit of material to bring to Lille...

The representation of our companies with high standing actors.

the small problem that was slightly &^ù*$^-'{[|\&& during the trip, and its solution :)

trip to the belgian coast

the stuck mobile home...

hummm.... what was the problem again? haaa maybe the next time it will be better to set the battery charger to charge mode ;)