Bests & Worsts Reviews from Amazon

Many aspects of this design seem well-thought out and well-executed, but unfortunately I cannot endorse it with anything resembling a positive review because of some indefensibly poor design choices. The most significant of these can be summarized in two words: "C batteries". There is absolutely zero reason to rely solely on a legacy technology such as this. I haven't purchased C batteries in going on 20 years, and I haven't purchased non-rechargeable primary cells in close to 10 (I started using LSD NiMH exclusively years ago, because buying disposable batteries is for rubes). The manual states that the device will not work with rechargeable batteries, which I suspect is not too far off from the truth. The batteries are all in series, with the nominal 6 volts being regulated down to ~5 V. I decided not to reverse-engineer the power section because portions of it are blocked by the battery cradles (which are soldered directly to the main PCB), but I do not see component to implement a buck-boost converter which would be necessary to fully discharge 4 batteries supplying 5V, so I suspect your already overpriced C batteries will "need" replacement with as much as 30% charge remaining. More investigation would be needed to confirm this, but as C batteries are an absolute nonstarter anyway, I stopped reverse-engineering and elected to modify it to add an actual power supply so it would be usable by people who aren't stuck in the 1980s. Unfortunately, it took quite a while to find a satisfactory place along the back of the enclosure to install a panel-mount barrel jack (if anybody is interested, I can show photos of my modification). If you think I'm making a mountain out of a molehill, I would merely point out that on the same day I purchased this feeder for $150, I purchased an automatic dispensing feeder for about half the price, which provided an option to use batteries OR external power. The DC input is a USB port and the power adapter is an el-cheapo phone charger style SMPS, but so what? It works. For $150, I should not have to be drilling into the enclosure, soldering power connectors, or making any modifications whatsoever to achieve basic usability. I am not going to reintroduce the legacy product which are C batteries into my "supply chain" under any circumstances, because they are obsolescent, expensive, bulky, and generally impractical in the era of cheap switch-mode power supplies and lithium batteries. Also, if it were me, I was have used torquier motors with less gear reduction, and hopefully reduced the rather loud and obnoxious whirr with a softer, quieter sound less likely to annoy timid cats. There's plenty of wasted space to accommodate this, especially if they had used sensible power solutions instead of something which is distinctly archaic compared to the rest of the design as C batteries. Hire a power engineer, guys! Or fire the one you have, assuming he hasn't retired already. I've seen better power solutions on Wun Hung Lo consumer products I've purchased direct from China via Alibaba. Shameful!