Various Projects – EvertDekker.com

5Aug

Various Projects

Raspberry Pi Power distribution board

At the moment I have 4 raspberry pi’s running 24/7 for various tasks. Some of these tasks are Node-red, Pi-hole, Vpn server and 3 music streamers.
All these’s pi’s need power and all those power plugs are occupying the outlets in the hall way closet. To reduce the required outlets I designed this power distribution board.
The second reason for this design is that the pi3 and 4 are trigger happy to give an “under voltage detected”. This is because there’s an diode in the 5 volt rail that will has some voltage drop over it. Due this voltage drop the under voltage will trigger very vast. Increasing the input voltage to 5.2V will prevent the above.
There are also some 3.3V output’s for future use.

Added a current and voltage display for monitoring and quick trouble shooting in case of a problem, and for the “looks nice” off course.

Under the pcb there’s a 5V 50w power supply from Ali. This supply has a trimmer to adjust the output voltage, so it could be increased to 5.2V.

For the output connectors there where 5.5mm connectors used with screw lock, you don’t want by accident pull out one of the power supply cables. All the outputs have a 3A fuse.
Cables between the power distribution board are home made. To be honest they are half home made. Bought some thick (3A fast charging) usb to usb-micro cables from Ali and cut off the usb connector and mounted the 5.5mm plug.

The pcb’s are ordered from Jlcpcb.com. Good pcb quality, however they messed up the milling for the display, they forgot to subtract half milling diameter to the given dimensions so the hole is a bit to big. Complaining doesn’t help, it’s always the customer his fault. Next pcb I’m going to order my pcb from Elecrow.com again.

Pcb Front

Pcb Back

Up and Running

7Oct

Various Projects

Raspberry Hat board template Altium

Raspberry pi hat board template for Altium designer (16) if you like to design you own add on board.
Template made according the Raspberry specs.
For Raspberry with 40p connector.

Raspberry hat

Download Now!

3777 Downloads

30Dec

Various Projects

Making of the CoLinkEx

How did I made my pcb version of the CoLinkEx…

First of all I borrowed most of the schematic from Coocox. Made some minor changes for components that are not that easy available in Europe and ported the schematic to Eagle.
Uploaded the gerbers to my pcb manufacturer Elecrow.com in China, there are cheap but delivery can take up to 3 weeks, doesn’t matter if you’re not in a rush, the price and quality is perfect.

Because the plan was to make 5 pieces of the CoLinkEx and there are some fine pitch chips on it fabricating them would be the easiest with the stencil and reflow method.
For this small amount of pcb’s a stencil made from polyester will do the job fine. From Smtstencil.co.uk you can order an a4 stencil for around €15. You can put as much designs on it as you like. I prefer the 100μm thick sheets, there applying enough solder paste to the pcb.

First we have to make a framework to hold the pcb steady and align the stencil correct.
The framework is easy to make from some pcb leftovers that have the same thickness as the Colinkex pcb, standard pcb is 1.6mm thick. Glue the pieces on a bigger pcb leftover or other material. You can use almost everything for this.

Put the pcb in the framework and align the stencil exact as possible with the pcb. Then tape the stencil on 1 side to framework.

When the pcb is removed you can see clearly the cutouts in the stencil.

Now lets apply the solder paste. Put a line of solder paste as wide as the pcb is on the same side as you have applied the tape.
Smear the solder paste with an spatial over the pcb. First run hold the spatial in 45 degree angel to push the solder paste in the cut outs. Smear always from the tape away to prevent moving of the stencil.
Second run hold the spatial in almost an 90 degree angel to “scrape” off extensive solder past.

Lifting the stencil and voila , nice layer of solder paste. After removing the pcb carefully I repeated the previous step to apply solder paste to the other 4 boards.

Looks like it’s completely failed, especially the fine pitch (0.5mm) LPC1343FBD48 cpu. But when reflowing all the solder paste will end up on the leads due the capillary force.

Placing all the components on the pcb, just put them exact as possible in the solder paste. A little bit out of alignment is not the worse, during reflowing it will correct itself.
In this video from an other project you can see how the components will align them self when the solder melts in the oven.
Still missing some components, I thought that everything was on stock. Doesn’t matter can place these components later an solder them by hand with an iron.
Now time to place the pcb in the oven to reflow it.

Finished reflowing. Added the jtag header, still waiting for some components

All parts are in, finished now soldering the board.

It’s alive, working well.

26Dec

Various Projects

CoLinxEx Jtag debugger

For my projects that are arm based i needed an Jtag debugger and programmer. Because i was already using the free CooCox ide it would be also nice to have the CoLinkEx jtag debugger. It’s design and firmware are also free.

I decided to design my own pcb, it was (not yet) possible to buy it somewhere else.
Here it is, if you are intrested in a complete build and tested pcb or an bare pcb, mail me.

Update: Have a look at making of the CoLinxEx

Schematic

3d Design

Bare pcb

Finished pcb

28Jun

Various Projects

µCurrent, Precision nA Current Measurement

For a project at work I needed to measure precise the power consumption of a watch that I was developing. The power consumption was something like 17µA when running and 1.5µA when standby.
Normal multi meters have what the call “burden voltage”. This is the voltage that the internal current shunt resistor drops as you pass your circuit current through it and can have an big influence on the measuring.
To avoid this I want Dave Jones from EEVblog his µCurrent meter, but unfortunately it’s was sold out and not produced anymore.
Time to build one myself. Dave was so kind to share the schematic and pcb design, makes it all a lot easier.
I made the first pcb for myself on the milling machine at work. Had to make some minor changes so that the pcb fits in enclosures that you can buy easy here in the the Netherlands, same for the the binding post.
Friends and colleagues liked it that much that the also want one. Time to order some pcb’s in China, red ones to make them as beautifully as the original from Dave.

I’m very happy with this meter, is does what it needs to do. Compared with our old Goerz analog meter and it’s very accurate.
Still have some kit’s leftover, if your interested to build one yourself mail me.