The arrival of parcels is always exciting for me. Even if it is just an Amazon box containing an audio cable, I still get a little excited, so naturally, when this arrived at my door, I was VERY excited.
The box arrived within a few days of the e-mail telling me that I had been accepted into the challenge. Considering that I am in the UK, this is especially impressive. Naturally, my first reaction was to open everything and lay it out onto my bed (I had just had guests and my desk was still not cleared). Strangely enough, the Arduino proto sheild came in a separate envelope from a UK warehouse in order to ship faster to the UK. It is nice to see that fast shipping is given such a priority. Unfortunately the Gun has not arrived yet, but everything else was included in the box. Also, kudos to Atmel for including a USB cable with the explained board. One of my micro B cables recently suffered some sort of internal failing, leaving it unable to charge my tablet at a reasonable speed. The new one is now a significant part of my cab.
Strangely enough, I have never owned an Uno. My only Arduino up to this point has always been a Leonardo, thanks to the extra IO, reduced cost and keyboard emulation. I was really excited about the ease of use with extra library's and ability to swap chips. What I did not realise was how much faster it would be to upload sketches. Uploading sketches to the Leonardo is not too difficult after the first time, and did not expect the Uno to blow me away in this area. In reality, after the sketch compiled, it would upload several times faster on the Uno. I still like my Leonardo, but the Uno is going to be a valuable addition to my toolkit.
My first stage of testing was to remove the display from the meter's circuitry and hook it up to a 5v power supply to see if the dial would reach full deflection. Thankfully the dial had convenient positive and negative labels for the terminals. I briefly tapped the terminal and the dial immediately went off the scale. This may change my approach to the design for project. It may be possible to commit the motor driver and circuitry from the multimeter and instead drive the dial via a pwm pin from the Arduino via some resistors to limit the current. Of course this depends on the power required to drive the dial and whether the Arduino is capable of supplying the required current. If this is possible, then I may instead use the LED driver I was sent to implement a more interesting backlight.
I also noticed that the cover for the display was held on only with sellotape. This potentially means I could remove the cover and polish out some of the scratches that it has picked up over the years. However, my experiences with polishing plastic have been universally disappointing. If you have any advice on how to polish it, or on any other aspects of the protect, please feel free to leave it in the comments section.
NOTE: My new computer setup is still causing me some issues in producing these blog posts. I will attempt to continue posting from my backup device but expect some delays in posts. Strangely enough, comments are not being impacted.