Home > Brew gear, Tech geeks > I’ve got the power

I’ve got the power

As I indicated in my previous post, I was somewhat concerned whether the VAA505 component was going to be stable enough and adequate to power my PICAXE. Over and over I have heard that one of the most important aspects of designing and coding your own microcontroller circuits is a stable power supply – and these PICAXE chips are pretty sensitive to that. After fighting how exactly to connect to the various posts, I settled for some alligator clips. That allows me to have solid connections without having to solder wires to the posts (which would essentially ruin it for ultimately mounting to a PCB). After fighting some stupid mistakes in my download circuit wiring, I managed to get the memory cleared on the chip and upload a simple test that blinks the green LED every 1/2 second.

This is very encouraging – I will be picking up a couple more of these power supplies in my next order to Allied Electronics, since I need to order another SSR for the mash tun top-up pump circuit. At US$17, they really are a good deal considering buying an AC transformer, bridge rectifier and all the other nonsense it would take to build your own stable 120VAC->5VDC power supply would probably cost about the same – and this is super-compact and off-the-shelf.

I actually did a very quick test using the SSR, the cooling fan, and the picaxe all wired into the same voltage source (an old computer cable & receptacle I scavenged from an old system) – No problem! The Crydom SSR switched on my pump, the cooling fan kept cooling, and the PICAXE didn’t miss a beat while I played around. When I have a little more time this weekend, I plan on building the test rig for the grant, wiring in the float switches, and coding up the PICAXE 18X chip…. truly prototyping the system, in other words.

My development area is a total mess, and I need to do some housekeeping before that happens.

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Categories: Brew gear, Tech geeks
  1. davemccomsey
    May 25, 2008 at 10:54 am

    i have a 100va 120v to 24ac/24dc powersupply if you want it. the DC is variable down to 1.5v. i was at your demostration on homebrew a couple week ago. you can have the power supply, i have plenty from work.

    dave

  2. brewznet
    May 27, 2008 at 12:26 pm

    Hey Dave! Thanks for swinging by and checking out the blog. Sorry it took a couple days for me to get to the comment moderation – been really busy with the family over the holiday weekend.

    I appreciate the offer, and may have to take you up on it. This first part of prototyping the grant is the “easy” piece – the main unit will have to control a LP gas valve, and most of those I’ve seen while shopping around on Grainger.com were 12V control signals, so that means I’ve got 120VAC, 12VDC and 5VDC all running around together – UGH.

    Hope you enjoyed the demonstration, and that we’ll run into one another sometime!

  3. davemccomsey
    May 28, 2008 at 11:52 am

    if you get a 24vac solenoid valve then my powersupply will work for all your needs. i hvae a case of them, you can have all you need 🙂 also have some small 24vac/24vdc converters that i think are adjustable.

    didn’t you say how you liked brewing to be easy 🙂

    dave

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