Fluid64

Fluid64 is a board with 64 analog in/outputs developed by Fluid Forms and Snow Reporter. Fluid64 is used in the Cassius Boxing Bag project to receive force and position of punches throught the 63 force sensors. It consists components layed out in a similar manner to the Arduino Nuove Generazione (NG). It also has four 16 channel multiplexers that turn four analoge inputs into 64. If you would like to have the board printed you can download the Fluid64 Eagle layout file. If you would like to get started right away we have a few boards left over that we can sell you. Just send us an email.

In the following tutorial you will read how to...

Print the Board

A freshly printed board with on components

You can download the Eagle Layout File and send it to a board printer. You may find that the price for one piece is very similar to the price of 10 pieces.

Solder the SMD Components in a Mini Pizza Oven

To solder the ATMEGA8 (you can also use a ATMEGA168), the USB controller and the multiplexers you simply squirt a line of soldering paste along the boards contacts.

Squirting the soldering paste onto the contacts A fully squirted board

You then place the chip onto of the paste so that the pins line up with the contacts.

Placing the SMDs

When you have squirted all the contacts and placed all the chips, put the board in the oven and turn it up to full.

Place the board with the SMDs in the oven Place the board with the SMDs in the oven

We use heat resistant wires connected to a multimeter and a heat sensor to accurately measure the temperature.

Chart Soldering paste melting
  1. Preheat Phase: The oven should take about 100s to get up to 175°C.
  2. Soak Phase: Turn the dial back and maintain 175°C for a further 200s
  3. Reflow Phase: Turn the dial up again and let the heat raise over the next 90s to 220-240°C
  4. Cooling Phase: Slowly turn the dial back to the off position allowing the board to gradually cool down to room temperature.

This method of soldering is called the Reflow technique. In the prehead phase the flux melts and enables the tin to flow onto the boards contacts. In the soak phase the temperature is increased to equally raise the temperature of the board and each element on it. During the reflow phase the tin melts and binds the contacts to the components pins. Slowly allowing the board and components to cool enables the tin to reach room temperature without getting any cracks.

Check the Contacts

Removing excess solder

You may have some short curcuits at this stage due to too much solder. You can use your soldering iron and a copper mesh wire to melt and soak up excess solder.

Solder the non-SMD Components

Solder the rest

The remaining components can be soldered with your soldering iron, so welcome back to the dark ages.

Build a Programming Adapter

In order that we can program the board over the usb port we will have to set the fuses and upload the bootloader. To do so we need to connect a programming adapter. You can make your own by connecting... ************** TODO : explain and show photos ***************

Set the Fuses

Fire up you Linux machine, make sure "uisp" is installed and enter the following command...

uisp -dprog=stk200 --wr_fuse_l=0xFF

Load the Bootloader

By loading the hex file, you will load the bootloader and the software we use for reading the Cassius punch sensors.

uisp -dprog=stk200 if=myhexfile.hex --upload

If you want to do something else with the board you can now treat the board as if it were an Arduino NG. Fire up the Arduino IDE and start coding.

Arduino NG