Auto frozen food feeder

ReeferAl · Oct 12, 2017

This is the DIY feeder I've been using for about 10 years. It is designed to feed small amounts of (thawed) frozen food about every 60-90 minutes throughout the day. It has several components:

Mini fridge to keep food chilled as cool as possible.
Container to hold the food, suspended in water.
Stirring motor to turn a propeller before each feeding to suspend the food throughout the container.
Peristaltic dosing pump to send the food from the container to the tank. This also prevents any back-flow into the container. 4a. Flow loop from sump to feeder and back to sump.
Board to control the feed cycle.
Timer to initiate the feed cycle. I do this with the Apex.

ReeferAl · Oct 12, 2017

Here are some photos of the working feeder.

ReeferAl · Oct 12, 2017

The controller board is a relay designed for home security systems but I'm sure other boards could also be used. It allows the feeding cycle to be initiated with a low voltage trigger signal and allows the dosing pump ON-time to be adjusted down to about 1 sec. The pump I use spins pretty fast so about 1 sec per feed is plenty. Only a small amount of liquid is added with each feeding so it really doesn't affect salinity. The jar is 1 gallon and is dosed over about 6-7 days. Here's the board I've used very successfully. It is model 6030:

MaddyP · Oct 12, 2017

I’ve been searching for an appropriate mini fridge to accomplish this on a smaller scale. It seems technology hasn’t yet miniaturized refridgeration to the proper level.

Love the project, great job!

Larry L · Oct 12, 2017

Nice setup. Now you just need a hopper to automatically drop food cubes from the freezer section into the food jar!

ReeferAl · Oct 12, 2017

Larry L said:
Now you just need a hopper to automatically drop food cubes from the freezer section into the food jar!

I've tried that but so far haven't gotten the bugs out so I shelved the idea. Figured I'd stick with my tried and true method.
A while back I bought an auger assembly taken out of a commercial ice dispenser. What I would really like to do with it is have it turning very slowly but continuously all day. I can't find any motor capable of doing that though. They're either too fast or have insufficient torque. Some day I'll give it another go with the new auger assembly. I'd like to have it drop cubes or chopped food directly into the sump
One problem I've found with small fridges or freezers is that they use the outer metal shell itself as the outside heat ex-changer. That makes it very hard to make any holes in the sides or top because you never know where the refrigerant tubing will be running. The back seems to be safe though.

Allen

ReeferAl · Oct 12, 2017

I would also caution anyone against using thermoelectric chillers. I tried and they can't keep the fridge cold enough and just don't last.

sbash · Oct 12, 2017

ReeferAl said:
The controller board is a relay designed for home security systems but I'm sure other boards could also be used. It allows the feeding cycle to be initiated with a low voltage trigger signal and allows the dosing pump ON-time to be adjusted down to about 1 sec. The pump I use spins pretty fast so about 1 sec per feed is plenty. Only a small amount of liquid is added with each feeding so it really doesn't affect salinity. The jar is 1 gallon and is dosed over about 6-7 days. Here's the board I've used very successfully. It is model 6030:

Great idea, I never thought to use a dosing pump! Do you blend your frozen food? Some of the stuff I get would run the risk of clogging the pump...

MaddyP said:
I’ve been searching for an appropriate mini fridge to accomplish this on a smaller scale. It seems technology hasn’t yet miniaturized refridgeration to the proper level.

What about this? https://www.amazon.com/Gourmia-GMF600-Portable-Fridge-Cooler/dp/B00DQT2ZGE

MaddyP · Oct 12, 2017

sbash said:
What about this? https://www.amazon.com/Gourmia-GMF600-Portable-Fridge-Cooler/dp/B00DQT2ZGE

It isn’t likely this would keep the frozen food cool enough to stop it from going bad. I’ve looked into these smaller fridges, but most only cool to around 55 degrees.

sbash · Oct 12, 2017

MaddyP said:
It isn’t likely this would keep the frozen food cool enough to stop it from going bad. I’ve looked into these smaller fridges, but most only cool to around 55 degrees.

Interesting...

Makes sense! Even in my proper fridge, at 4-5 days, the smell starts to get a bit funky...

I wonder if these smaller fridges can be modified... Fridge/freezer tech is pretty simple....

MaddyP · Oct 13, 2017

sbash said:
Interesting...

Makes sense! Even in my proper fridge, at 4-5 days, the smell starts to get a bit funky...

I wonder if these smaller fridges can be modified... Fridge/freezer tech is pretty simple....

Hmm...you pose an interesting prospect! I’ll do some research on this tomorrow.

ReeferAl · Oct 13, 2017

I do not chop up or blend the food in any way but I do use tubing with 3/8" ID so pretty big stuff goes through it without difficulty. With smaller tubing you would either have to chop the food or use only smaller food. Copepods, daphnia and even brine shrimp could go through fairly small tubing but I wanted to include Mysis and small krill (pacifica sp.) so I needed larger tubing. Not sure if 1/4" ID would be big enough. That's certainly and easier size doser to find than 3/8".
As far as food going bad, I haven't seen any problems with food up to a week old, but then fish also make it a habit of eating things like the poop of other fish so I don't think they're as particular as humans. If that worries you, you could always do a new mix in 3 to 4 days instead of 7.

Allen

ReeferAl · Oct 26, 2017

I've played around with the idea of building a prototype chiller specifically for dispensing "frozen" food but dealing with compressors and refrigerants is just not practical without the right skills/training.
My ideal system would have a pot, probably stainless steel, which would drop into a well surrounded by chiller coils. The stirrer would be incorporated into the lid and the peristaltic pump head would also be kept chilled. Maybe someday a refrigerant specialist with a reef tank will take up the challenge.

atx100r · Oct 26, 2017

Check out this setup...

revhtree · Oct 26, 2017

Very cool!

Heliarc19 · Oct 26, 2017

ReeferAl said:
I've played around with the idea of building a prototype chiller specifically for dispensing "frozen" food but dealing with compressors and refrigerants is just not practical without the right skills/training.
My ideal system would have a pot, probably stainless steel, which would drop into a well surrounded by chiller coils. The stirrer would be incorporated into the lid and the peristaltic pump head would also be kept chilled. Maybe someday a refrigerant specialist with a reef tank will take up the challenge.

We actually fabricate this setup but on a slightly larger scale (tank is 7.5 gallons) but very similar to what you described. They are for the cattle ind. to store and chill enzymes to add in feed. My personal problem to make them would simply be cost. Never thought of using one for this!

ReeferAl · Oct 26, 2017

Dispensing liquids and very fine particulates is relatively easy. My goal was to be able to dispense rather large food items- specifically up to full-size Mysis. My set up does that very well.

Allen

Heliarc19 · Oct 26, 2017

ReeferAl said:
Dispensing liquids and very fine particulates is relatively easy. My goal was to be able to dispense rather large food items- specifically up to full-size Mysis. My set up does that very well.

Allen

Awesome

Drakonis · Oct 26, 2017

Office water cooler... i have one i been meaning to repurpose. stainless bowl, cooling coils around it and already plastic plumbed out bottom of bowl.

FugeTown · Oct 26, 2017

atx100r said:
Check out this setup...

I have one suggestion for your fridge, that top shelf on the door Is empty throw a couple beers on there and while your doing maintenance in the fridge you can crack a beer