At Hashtek, we’re always looking for innovative and cost-effective solutions to help hashmakers. Recently, we shared a YouTube video on how to create a Coolbot Alternative for $80-120, compared to the $400+ Coolbot equivalent. The response was overwhelming, and many of you asked for more details. To help, we’ve created a step-by-step guide with a diagram to show you how to trick your AC into going below its minimum set point.

Why a Coolbot Alternative?

A Coolbot is a handy device that can help transform a standard air conditioner into a cooling system capable of maintaining temperatures much lower than what the AC was originally designed for. This is particularly useful for creating walk-in coolers on a budget, without the need for expensive commercial refrigeration equipment. Many hashmakers use this technique to keep their work environment cool and efficient.

Materials Needed

Before we get into the instructions, let’s go over the materials you’ll need to build your own Coolbot Alternative:

1. Inkbird Temperature Controller (model ITC-308 or similar)
2. 4W Lightbulb (or another small heating source)
3. Extension Cord (if needed)
4. Electrical Tape
5. Thermometer (to monitor ambient and AC temperatures)
6. Air Conditioner (make sure it’s not already maxed out and can hit its set point)
7. Sensor Push with Wifi Gateway (for remote temp monitoring and logging)

Step-by-Step Instructions

Follow these steps to set up your Coolbot Alternative:

Step 1: Prepare the Inkbird Temperature Controller

1. Unbox the Inkbird Controller and familiarize yourself with its components. The controller has one temperature sensor and two outlets: one for heating and one for cooling. We will only be using the cooling outlet on both units.
2. Set the Target Temperature: For our purposes, set the target temperature on the Inkbird controller to 34°F. This will be the desired temperature for your walk-in cooler.

Step 2: Set Up the Heating Source

1. Wrap the AC Ambient Temp Sensor: Take the 4W lightbulb (or your chosen heating source) and wrap it together with the air conditioner’s ambient temperature sensor using electrical tape. This trick will fool the AC into thinking the room is warmer than it actually is. You can also insulate this if you wish but a 4w light source will not be a massive heat source.
2. Plug the Heating Source: Plug the heating source into the cooling outlet of the Inkbird controller. This will ensure the lightbulb heats up when the ambient temperature drops below the set point.

Step 3: Place the Temperature Sensors

1. Ambient Room Sensor: Place Inkbird 1’s ambient room temperature sensor in the area you want to cool (e.g., your hash lab). This sensor will monitor the actual temperature of the room.
2. AC Fins Sensor: Place the second Inkbird temperature sensor in the fins of the air conditioner. This prevents the AC from freezing up by accurately monitoring the fin temperature. This inkbird should be set to 34F or 2C. You can increase this set point if you have freeze up happening in the fins.

Step 4: Connect the Inkbird Controller

1. Plug the First Inkbird into the Cooling Outlet of the second Inkbird: this ensures that if the fin’s get too cold the light bulb will lose power and the fins will have a chance to thaw out.
2. Plug the second Inkbird into the wall.

Step 5: Monitor and Adjust

1. Power Everything On: Turn on the Inkbird controllers and the air conditioner. Monitor the temperatures using a room thermometer to ensure the system is working correctly. We love the sensor push monitors for data logging! Especially when paired with their wifi gateway for remote alerts.
2. Adjust Settings if Necessary: If the temperatures are not reaching the desired set point, adjust the settings on the Inkbird controller or reposition the sensors.

Important Notes

• Ensure Your AC Is Not Maxed Out: This technique only works if your AC is not already maxed out and is capable of hitting its set point. If the AC cannot reach the desired temperature, the setup will not work effectively.
• Insulate your room: This hack does not get around the need for insulation. Without proper insulation you will be limited with how cold you can get the room.
• Budget-Friendly: This DIY Coolbot Alternative allows you to create an affordable walk-in cooler, saving you money on commercial refrigeration equipment.
• Secondary Sensor: Some larger units will have a secondary sensor that will need to be removed as well. Both the primary and secondary sensor will need to be wrapped together with the heat source.

Compatible Units

See below for units that tend to be compatible with this hack. Thank you to coolbot for compiling this information. Their preferred brand is LG.

Conclusion

Building your own Coolbot Alternative is a fantastic way to maintain a cool environment for your hashmaking operations without breaking the bank. By following these steps and using the right materials, you can create a reliable and efficient cooling system for your workspace. Happy DIY-ing, and let us know how it works for you!

For more DIY tips and tricks, follow our Hashtek Open Source blog and join our community of innovators and hashmakers.

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