Cheap Arduino brew monitor

Martin and his friends started brewing beer at home. They started with simple and manual temperature monitoring which appeared to be inconvenient. First of all you need to be in place to check fermentation temperature. So they started looking for simple system that would read temperature and plot data on the web. They found out that most of them are over budget or require significant effort in configuring. So they started their own Brewmonitor.


They took cheap Arduino clone and connected DS18B20 temperature sensor. Then they used ESP8266 Wi-Fi module for internet access. By using POST method they were able to post temperature values to web-server with PHP and MySQL. AngularJS front-end graphs data and refreshed it every time page is loaded. From this point system can be further upgraded by adding freezer/heater to sustain required temperature. But again, additional features may rise overall cost. Keep an eye on project at Git.


Simple Arduino experiments with nixie

Kevin is collecting parts for his nixie clock project. But before starting he played couple experiments on starting and controlling IN-12s and In-3s nixie indicators.


In order to start IN-3s there is 90 volts needed. He had 170V step-up converter board, so he added 68k resistor in series to get to required level. Next step was to connect to Arduino. For this purpose he used MJE340 power transistors. After this successful experiment he will head straight to clock project.


Raspberry Pi power supply with backup solution

Raspberry Pi basically runs on Linux which takes time to start once powered. If you have designed some hardware solution which controls valuable things, you probably don’t want it to fail on power failures. Like for desktop computers there UPS used, same technique can be applied to Raspbbery Pi. The only difference is scale of things. Juice4halt shares Raspberry backup power solution. He uses couple supercapacitors for energy storage.

Since supercaps are low voltage like 2.7V there is step-up/down circuit needed to take care of charging and draining power. He made whole power board that sits on top of Raspberry Pi. It carries two independent Ds/Ds converters where on is used for charging supercaprs in step-down mode and powering board from them through step-up converter. Another DC/Dc converter is used as front end step-down converter which converts input voltage in to 5.1V. This is convenient for using any wall DC adapter. With two 25F 2.7V supercaps and 375mA constant current draw on Raspberry Pi it is capable to supply for about 61second. So it can withstand short power failures. If you need longer times, probably adding more supercaps should help or think of normal UPS.


RPi board for learning Python

Python is popular programming language used in Raspberry Pi. It is easy, intuitive and well documented. With Raspberry Pi hardware you can access physical pins and do lots of crazy things. Anyway like any new thing you need to learn it. TO make thing much easier, jechavarria introduced Rpi board which is dedicated for learning Python on Raspberry Pi.


Rpi board has four 10mm diffused LEDs – each different color. Each is controlled through Mosfet transistor key. Then there are couple push buttons that are lined with LEDs and in the middle there is a buzzer which is also driven through transistor key. On top of it Rpi board carries 2×16 LCD. Additionally you can see I2C buss connector for future extensions and. Couple green LEDs on a side are just for indicating 3V and 5V power supply. Rpi board mounts on top of Raspberry Pi model B (or A) and should fit on B+ model. He also provides few Python code examples to get started with.