2 February 2020

I rent a house which has an absolutely brilliant robotic cleaner called a ‘Dolphin’. It works well except you have to switch it OFF, wait 20 seconds and then switch it ON again for it to operate.

Apparently the next model up has a bluetooth interface for many hundreds of dollars more. If I want that option, after the fact, I would have to replace the whole cleaner…not great news!!

I thus set-about making a “robotic finger” to mimic this action every day, at a set time.

I use the famous Raspberry Pi 3. The first version of the ‘Robotic finger’s was, ummm… unreliable mechanically, I thus redesigned it. It also has a camera which shows me that the pump is running and the LCD display of the Davis pH meter. The first version is shown below:

RS485 which communicates with the Zodiac variable speed filter pump. A relay which operates the mortice lock which pushes the touch panel ON and OFF switch of the pool cleaner – this is the ‘Robotic finger’. A relay also operates the master controllers input contact for the Zodiac (which is the most reliable method to start and run the pump)
The RPI 3 takes a photo everyday of the Davis pH meter and the indication of the pump master controller and publishes this photo to a Jekyll website

The ‘Robotic finger’ work-bench tested as follows:


2 February 2020

Biltong is usually not allowed to get as dry as Beef Jerky and uses different spices

There are many ways to make a food desiccator. My preferred way is to use my fan with heater mounted on it as, shown in this post:


I have also made one using to microwave oven fans and a microwave often lamp, for the heat source. This one uses the Wemos Lolin32 with OLED display…which reports temperature, humidity and heat index as well as the low and high set-points of the temperature control band. The photos are as below:

Basket with shade cloth for drying fruit are laying meat down
Aluminium drip trays fitted to the bottom and a fan drawing in air from either end (vented out of lid)
Wemos Lolin32 doing service in controlling the heat source between the two set-points (temperature and humidity from a DHT22 sensor)