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A General Applaince Temperature Controller

Version 5 Release - March 2015

The YATC5 is designed to make the fermentation of foods as easy as possible. Version 5 has many unique features.

  • Waterproof - 3' long temperature probe
  • Datalogging - drop in bluetooth module or TTL serial
  • 100% Open Hardware
  • Digital Display
  • Celsius or Fahrenheit configuration
  • Memory - save settings through blackouts
  • Wide Temperature Range ( -67F to 257F) ( -55C to 125C )

Choose Kit or Assembled unit from drop down menu below.

All shipping is Priority Mail based on the country you are located in, as follows:

  • United States - $5.95
  • Canada - $20.85
  • International (Australia / Europe / etc.) - $25.25
Please choose the correct item and country to avoid additional fees and delays. The shipping is included in the following prices.



  • sous vide ( 132F - 185F )
  • chest freezer to refrigerator ( 35F )
  • bread rising ( 78F )
  • cheese making ( 72F - 108F )
  • wine making ( 75F )
  • yogurt fermentation ( 110F )
  • kimchi fermentation ( 72F )
  • kombucha fermentation ( 74F - 84F )
  • tempeh fermentation ( 85F )
  • cheese fridge ( 50F - 54F )
  • wine fridge ( 50F - 57F )
  • soup stock ( 180F )
  • beer (ale 68-72 | lager 45-55)




  • Fully water proof temperature probe
  • 3-digit 7 segment LED digital display
  • Datalogging - external HC-06 bluetooth module (not included) or TTL serial
  • Heating versus cooling switch
  • Celsius versus fahrenheit switch
  • Tolerance: +/- 2F
  • Temp Range: ( -67F to 257F) ( -55C to 125C )
  • Max Swiching Amps: 10A @ 120VAC or 220VAC
  • Circuit Power Supply (included): 9V / 500mA
  • NEMA 1-15P 120/220VAC 2 prong Wall plug

Question:What kind of power does this work with?
Answer:This temperature controller supports the following power configurations:

  • 120VAC, 50-60Hz, 10A
  • 220VAC, 50-60Hz, 10A

Question:How does this temperature controller connect to a chest freezer?
Answer:The controller connects to the freezers power cord using a plug-in outlet. No soldering or crimping required. There is a additional cable included with the device that plugs into the wall and a temperature sensor which is placed in the freezer. The temperature controller acts much as a thermostat and makes no connection to the chest freezers internal controls. This means that YATC can be used in combination with any existing refrigerator or chest freezers that draws less than 10A.

Question:Does this device use a PID algorithm?
Answer:No. The firmware reads the temperature sensor every minute and receives a calibrated temperature reading.The YATC will turn on or off the relay based on the temperature set point.

Question:Do you ship outside of the US?
Answer:Yes! Nearly half my kits are sold internationally. I use USPS priority mail for all orders.


These instructions are for the yatcr5 controller which was released in March 2015. If you have a earlier kit please see
these instructions

Note: This kit makes use of mains power - 120 and 220VAC. Do not plug the 2 prong NEMA 1-15P cable into wall socket until completing the following steps below.

Blank PCB (top side)
Blank PCB (backside)
Step 3: Place and solder 28-pin IC Socket (U1)

Note:There is a dimple on this device. It should be oriented to the right side of the circuit board.

Step 4: Place and solder slide switches
  • (S1) - Fahrenheit vs Celsius
  • (S2) - cool vs heat

Step 5: Place and solder the 300 ohm resistors (R1, R2, R3) [orange, black, brown, gold]
Step 6: Place and solder a 1k ohm resistor (R1)[brown/black/red/gold]

Step 7: Place and solder Diode (D2)

Note:The black line must be on the right side of the circuit board.

Step 8: Place and solder the 16-pin 595 mux expander chip

Note:There is a dimple on both devices that needs to be oriented on the right side of the circuit board.

Step 9: Place and solder decoupling capactiors (C1, C2)

Note:Orient the minus sign on capacitors to the right side of the circuit board. The long leg must go in the square shapped pin.

Step 10: Place and solder 4,700 ohm resistor (R5) [yellow, violet, red, gold]
Step 11: Place and solder 2N3904 transistor. (Q1)

Note:Orient the flat side of the transistor towards the left edge of the circuit board.

Step 12: Place and solder 7-segment display (D1)
Step 13: Place and solder both the DC barrel jack (CONN3) and the AC cord receptable (CONN1)
Step 14: Place and solder the blue terminal block (CONN4)

Note:Make sure the open side faces the right edge of the circuit board.

Step 15: Place and solder the large AC receptacle (CONN2)

Note:This device has 2 solder points on the top side and one on the bottom side of the circuit board.

Step 16: Place and solder large blue relay (K1)

Note:The text should appear upside down.

Step 17: Place and solder the 2N3904 transistor (Q1).

Note:The flat side of the transistor needs to be oriented to the left side of the circuit board.

Step 18: Place and solder 5v regulator (U2). Place and solder both temperature push buttons (S3, S4)

Note:The text printed on the regulator should be facing the lower edge of the circuit boad.

Step 19: Squeeze your microcontroller leads to fit the IC Socket (U3)
Step 20: This is the amount of curve you are looking for on the leads.
Step 21: Install the 28-pin AVR Microcontroller

Note:There is a dimple on this device. It should be oriented to the right side of the circuit board.

Step 22: Solder female header for HC-06 bluetooth module or TTL uart access.
Step 23: Connect temperature probe to 3-pin terminal block.

Note:The wires must be connected in the correct order. The colors are labeled on the PCB.

  • top: red (vcc)
  • middle: black (gnd)
  • bottom: yellow (data)
Step 24: Flip Circuit Board and use plastic rivets to attach plexiglass base.


This device does not include the HC-06 Bluetooth module, but it is setup to accept one. These modules sell on Amazon for about $8. The module is rather simple to connect to. On my Mac I use the following steps.

  • open Bluetooth preferences
  • turn on bluetooth
  • double click on HC-06
  • press 'Pair'
  • the first 'pair' will fail.
  • press 'Options'
  • enter code: 1234
  • at this point the mac is connected to the module
  • bring up a terminal program (i use minicom)
  • serial settings: 9600 8N1
  • you will see temperature updates ever minute or when a switch is toggled on the yatc5




Limited Warranty In accordance with manufacturer, guarantees to the original purchaser that products chosen from our site will be free from defects in materials and workmanship for a period of 90 days from the purchase date. If you discover what you believe to be a defect, send it to us for inspection. We may either repair, replace, or return it to you at the sole discretion and direction of the manufacturer. Of course, normal wear and tear,alteration, or misuse, (as determined by the manufacturer) is not covered by any warranty. Except as provided above, no warranty of merchantability, fitness for particular purpose, or any other warranty express or implied.

Each product offered on this site, specifically including this temperature controlling unit, must be used according to the manufacturer's instructions and only for the specific purpose for which it was designed. Holy Scrap shall not and is not responsible or liable for any consequential damages, injuries, paralysis, or death arising from the use or misuse of the products purchased from us. By making a purchase on this site, you(the customer) and your heirs assume all responsibility of ownership, risks of use,and agree to hold harmless,Holy Scrap.com, its owners, managers, employees, and heirs for any damage, incident, or action,involving the product purchased.

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