All posts by David

Dual Core A5/M4 board and module using the Freescale Vybrid

While working at the formula student racing team I had the chance to develop a board with DDR memory and took it, the result did not make it into the car. But there are now several projects at the UaS RheinMain (Hochschule RheinMain) that use these boards.

This article is currently a stub, there is a new version of the board currently in testing, which will be documented and published here.

DSC_0289  DSC_0298   DSC_0305 DSC_0751

Battery Management Slaves based on LTC6803/LPC11C14

Since  the Formula Student project at our university dumped all electric vehicle activities I will now publish all BMS Slave designs used in the years 2013 to 2015.

The BMS Master was a hateable construction out of a dSpace MBA and some helping PCBs. The Slave boards have been proven to be robust, at least the hardware. There is one software on github which is a good starting point and has been run two years without major problems.

The project is not ready to use, but can be easily adapted to any electric vehicle. If there are any questions don’t hesitate to ask.

All hard- and software files are available at github.

Here are some pictures of the used boards:


DSC_0524 Kopie

Battery Management System using LTC6803-3 and AT90CAN128

In this post I want to notify the world of an OpenSource project I did last year, which I never published until I found a thread about these ICs on a forum.


This project went on as a student research project, I developed a Battery Management System for the Formula Student racecar SPR12e. You can find more information on the race team at this page. It uses LTC6803-3 slave boards with circuitry to support 6 temperature sensors with each slave and then uses the proprietary current based spi daisy chain bus to hand over the data to a AT90CAN128 based master. The master has circuitry to monitor the output voltage of the battery, has a >40V warning LED, a precharge current detection and driver for the large relais. There is also some stuff to give additional safety when the code running on the AVR fails.

Problems and missing features:
– Charging
– no SoC calculation / no current sensing
– Slaves draw unsymmetrical current in off state, should be fixed
– We had problems with data transmission when confronted with strong electro-magnetic-fields, although this could be a motor controller issue

What should be added/changed for a stable system:
– (Master) Remove voltage and precharge current measurement, add LEM DHAB S/44 socket and LEM LV 25-P
– (Slave) implement clean shutoff circuit as shown in datasheet

I know a lot of errors I did in the design and I am currently doing a second design for the racing team which uses LTC6803 chips and an onboard LPC11C1X for each slave to directly communicate over a CAN Bus with the master.
There is a lousy documentation in PDF, which brought me an good grade. You can view it here.

The github project can be found here.

Modding RealD 3D glasses to be 2D glasses

First post should be something simple to test out how to create an post.

So, something based off an idea of a friend. Since I sometimes get a headache watching 3D movies and a friedn of mine had modded glasses that had only one polarisation. This can be achieved by disassembling two glasses and exchange the right and left from one to another glass, so you have two right and two left lenses. You can not turn the lenses, because they are actually made up from two filters, the light has to pass them in the correct order.

So, the mechanical stuff is pretty easy. You can seperate the two halfes of the glasses by prying open starting at the joints. Then you can easily rip off the two halfes, only one got minor damage doing this.

Then cut the lenses to be exchanged, be careful not to take away to much. From then on its some glueing and youre done.