DIY Coolbot alternative
If you connect an AC to a temp controller without contingency to control the ice build up on fins within a day your AC will be a block of solid ice
No need to hook your AC up to another temp controler, you can mimic the coolbot with two inkbirds / STC controllers connected in a series and a 5 volt light bulb and 5 volt power supply - 40$ at most
This is from a similar thread in HomeBrewTalk - I wish I had thought of this!
Makeshift Coolbot
It uses two STC-1000 units in series, as stated in a previous post, but instead of connecting the a/c unit, the STCs trigger a small 5v light bulb.
I used two STC-1000 units, a 5v light bulb and a 5v power supply (old cell phone charger).
First, I connected the +wire from the power supply to the light bulb. Then ran the -wire to the first STC COOL relay; from there it goes to the second STC's COOL relay in series, and finally to the other pole in the light bulb. Cover the light bulb with foil, attach the A/C unit's temp probe to this fixture and cover with foil again.
Place the temp probe of either STC inside the A/C's evaporator fins, set the STC to 32. This will prevent the evap from freezing out. Use the other unit's probe as your room temp sensor, set it to whatever your target temp is.
Set your A/C to the coldest setting.
The idea is, just like with the coolbot, to trick the A/C into thinking the room is warmer than it really is, by heating the A/C's probe with the light bulb or whatever heater you want to use, while the STCs monitor both room and evaporator temperature and relay or cut power only to the light bulb. This way there's no need to mess with the A/C unit in any way, and you can use whatever A/C you want.
Good luck, when it comes to DIY projects involving fermenting, the beer nerds web sites are full of info!