Fisher Innovation FI-ATSCRP (2010)

The FI-ATCSRP (Fisher Innovation – Autonomous Temperature Controlled Solder Reflow Plate) is a autonomous temperature control unit that will allow you to use your hot plate of toaster oven to reflow SMD components on a circuit board. The system will autonomously configure itself without human interaction, thus allowing the system to be attached to any heat element.

Project Overview supports multipule distributed computing projects, so feel free to generate heat from a cause that best suits you. The easy to use user dashboard allows you to configure and modify your setup any time. All Data Furnaces are configured with a active and passive computing setup. This means if the project you are working for goes down, the passive project workload takes over, thus allowing for seamless failover and no loss of heat output.

The concept is actually quite simple – the majority of the world uses devices that create heat directly from an electrical source which has no purpose other then to create heat. What if we could create a device that could generate useable heat from the offset of hardware that performed a beneficial task?

Parts List

  • A heating source (hot plate or toaster oven)
  • An Arduino
  • A servo connected to the temperature control of the heating source (anyway you want, you can configure it in the code) – Sparkfun
  • Two momentary buttons – Sparkfun
  • Thermocouple Type-K Sparkfun
  • AD595-AQ Thermocouple Amplifier Sparkfun – I use the Thermocouple Sensor v1.0 Kit from MakerBot Industries Makerbot
  • LCD screen for visual output (I use a 16×2 5VDC HD44780 parallel interface chipset) – Sparkfun

Prior to using the hotplate setup the default configuration values must be updated to reflect your specific setup. Within the project code, the configuration values can be found and updated with ease. The will look something like the following.

/* Start User Defined Variables */

// Pin Connections
int ThermocouplePin = 0;                     // Thermocouple Pin
int ButtonOnePin = 6;                        // Button 1 Pin
int ButtonTwoPin = 7;                        // Button 2 Pin
int ServoPin = 9;                            // Servo Data Pin
int LCDBacklightPin = 13;                    // LCD Backlight Pin

// Servo Control
int ServoLowPosition = 180;                  // Position the servo is in to have the heat at low or off
int ServoHighPosition = 0;                   // Position the servo is in to have the heat at high

// Temperature Limits (all temperature are read in celcius)
int MaxDeviceTemperature = 260;              // The maximum temperature that we will allow the device to get up to
int ReflowTemperature = 255;                 // The temperature we expect the board to reflow at

// LCD Screen
boolean LCDBacklightOn = true;               // If we should turn the backlight on or not
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);   // rw on pin 11, rs on pin 12, enable on pin 10, d4, d5, d6, d7 on pins 5, 4, 3, 2

/* End User Defined Variables */
Reflow Timing FI-ATSCRP

To properly get the solder to reflow and set you need to heat it up and cool it down in a precise manner. The graph to the left displays the manner in which my Arduino sketch will run. By reading temperature values via the thermocouple, we can then modify the hot plate temperature via the servo control. Once the temperature is updated we can verify the change again and continue the loop.

Hotplate Temperature Control

One of the trickiest parts of getting this device to work properly is allowing the servo to sweep and set the heating devices temperature from 0 degrees to full power. I found the majority of hot plates use a 180 degree rotation which works perfect for a standard servo. If you have a device that rotates more then 180 degrees I would recommend using a full rotation servo that can spin without stopping at a given degree or rotation.

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Email: fisher.matt at