From 234c904463e3ed11a73cf2609baa663fd79c3240 Mon Sep 17 00:00:00 2001 From: Anton Sarukhanov <code@ant.sr> Date: Mon, 31 Oct 2016 20:43:02 -0400 Subject: [PATCH] Preserve links to circuit diagram --- content/Electronics/test-box.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/content/Electronics/test-box.md b/content/Electronics/test-box.md index ef02549..a048405 100644 --- a/content/Electronics/test-box.md +++ b/content/Electronics/test-box.md @@ -33,7 +33,7 @@ The test box would need to test for a few things to fully examine a piece of equ I decided early on that Test Box v2, or at least my first prototype of it, would be built around a Raspberry Pi. It can reliably run Linux, and is exceptionally cheap at $35\. I liked the ability to build multiple prototypes and replace parts easily. I found the $45 [Adafruit PiTFT 2.8" Cap Touch display](https://learn.adafruit.com/adafruit-2-8-pitft-capacitive-touch) an attractive proposition as well, as installation is almost entirely plug-and-play with the Raspberry Pi. My first PiTFT seems to be defective, as the touchscreen has a pretty bad jumpy cursor issue. When I reported this to Adafruit support, they told me to [wipe down the display with a dryer sheet](http://forums.adafruit.com/viewtopic.php?f=50&t=61328). This didn't help. I haven't had this issue with the second one. The box needed an Analog Digital Converter to perform the measurements, and the Raspberry Pi does not have one onboard. The [AB Electronics ADC Pi](https://www.abelectronics.co.uk/products/3/Raspberry-Pi/17/ADC-Pi-V2---Raspberry-Pi-Analogue-to-Digital-converter) is doing the job. It is an 8-channel 17-bit ADC, providing ample resolution for my needs. It is mounted on top of the Raspberry Pi in the photo to the right. A bit of research showed that the easiest way to measure resistance with an ADC would be to build a [voltage divider](http://en.wikipedia.org/wiki/Voltage_divider) circuit (a resistor, essentially) for each channel. With a bit of soldering, I had the core components of Test Box v2 completed. - +<a id="comment-97"></a> ## Prototype -- GitLab