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--- projects:infcu1 [2015/07/04 13:00] – infaddict
+++ projects:infcu1 [2016/09/08 14:49] (current) – Updated link to Uputronics upu
@@ Line 9: / Line 9: @@
 https://ukhas.org.uk/general:beginners_guide_to_high_altitude_ballooning
 https://ukhas.org.uk/guides:how_to_lose_your_flight
 http://www.daveakerman.com/
+===== Humble beginnings =====
+From day one I decided I would always try to "build my own" rather than buying off the shelf.  To me, the journey was just as important as the end goal so I wanted to enjoy the process of designing and building most things myself.  So I discounted pre-built tracking devices immediately.  I started by listing my primary objectives:
+  * Take still photographs of near space
+  * Take video of near space
+  * Gather some interesting statistics such as temperature and altitude
+  * Track the payload position as it flies
+  * Find my payload after it lands (obvious but not as easy as it sounds)
+I have hardly any electronics experience other than wiring the odd plug so decided I should brush up a bit.  I bought an "electronics for dummies" book and found it an excellent way to learn the basics.  There are many free websites with similar content.  When building your own tracker you need a basic knowledge of things like voltage, current, resistance, Ohms law and circuit diagrams.  I also taught myself how to solder as this is needed for both the tracker and also some antenna work.  Being new to electronics I needed to invest in several pieces of equipment such as a soldering iron, solder, breadboards, wire etc.
+===== Tracker Parts =====
+I decided to first focus on my tracker, the thing that would report the position of my flight and hopefully allow me to find it again once landed.  My tracker would comprise of:
+  * A GPS chip and antenna to find position, altitude and time
+  * One or more temperature sensors to record internal and external temperature
+  * Voltage detector to report current battery voltage
+  * Micro SD card to log flight details
+  * Various LED's to show good/bad status
+  * A radio transmitter to send position, altitude and sensor readings back down to the ground
+  * A microprocessor to control all of the above
+I quickly realised that the Raspberry Pi I had been bought wasn't best suited to the job.  Whilst it would work, it was a bit big and heavy and also operated at 5V which meant a bigger battery pack would be needed.  I decided on using an Arduino based solution that could operate at 3.3V and eventually chose the Arduino Mini Pro 8MHz 3.3V as my microprocessor.  I could now look for components to work alongside my microprocessor and needed to choose items that worked at 3.3V.  I also need to ensure any components worked ok at low temperatures as payloads can go down to -30 or lower when up high!  My final shopping list for my tracker looked like this:
+  * Arduino Pro Mini 3.3V 8MHz microprocessor
+  * HABsupplies uBlox M8C GPS break out board
+  * Radiometrix NTX2B-FA radio transmitter
+  * 2 x DS18B20 temperature sensors
+  * microSD trans flash break out board
+  * FTDI serial break out board (to allow me to program the microprocessor)
+  * Battery holder (4 x AA)
+  * Straight and right angled header pins
+I ordered the GPS and radio items from HAB Supplies (Now [[https://store.uputronics.com|Uputronics]]) and the rest from SparkFun, both of which provided great customer service with fast shipping.
+===== Wiring the tracker =====
+My main piece of advice is to download and read the datasheets for all your components before you start wiring things up.  They contain vital information about voltage/current requirements and what pin is used for what.  As with most hobby projects, I started with an empty breadboard and my first job was to get the Arduino microprocessor onto the breadboard.  I soldered 2 strips of header pins onto the Arduino board and pushed it into my breadboard.  I then connected the FTDI breakout board to the Arduino to allow me to connect my laptop via USB.