Category Archives: Buying + Sourcing

OpenPCR Packing Party

Many thanks to Eri Gentry and Will Reinhardt for helping pack the first batch of OpenPCR kits. We counted, double counted, bagged, and labeled thousands of parts, everything from the shoulder bolts in OpenPCR’s heated lid, laser cut cases from Ponoko, and individual screws and nuts.

Eri and Will packing OpenPCR thermal cycler bags

Eri and Will

Josh with the OpenPCR thermal cycler boards

Josh

Castle of OpenPCR thermal cycler boxes

Working late into the night

First OpenPCR kit assembled

It’s no secret that we’re fast approaching the shipment of our Kickstarter and pre-order OpenPCR kits. But today marked a new milestone: the first assembly of an OpenPCR by someone other than Tito or myself. Eri Gentry was kind enough to spend the day assembling an OpenPCR and giving feedback on our instructions, which we’ll role into the final printing. Here she shows off the completed unit, which will be housed at the BioCurious hackerspace:

The boxes you see in the background are OpenPCR components for the first kits. We’re just awaiting one more shipment from China (expected next week), and making some final software changes, and then these boxes are out the door.

Case Study: Rapid iteration with hardware

From Eric Reis’ blog, written by Ronald Mannak. (Thanks to Josh Perfetto and Matt Bertram for recommending it!). Excerpt:

The prototypes
The next day we started building the first prototype to see if the sensors actually behaved like they were supposed to, and to see if we could measure the sideway movements. The prototype was crude. Joris taped sensors on his arms with duct tape and started drumming in the air with wooden drum sticks (that did not contain any electronics). We connected the sensors to a seven year old pc with an Arduino-like interface that ran a simple drum program we developed. The results were amazing. It actually worked.

http://www.startuplessonslearned.com/2010/10/case-study-rapid-iteration-with.html

There is certainly a lack of good information on the business of hardware. Hardware sometimes feels like a dark art compared to Software where you can supposedly RentACoder at the drop of a hat, and oh just AB test your way to being a billionaire.

Got a favorite hardware blog? Give them a shout out here, I would love to hear about  them.

Tito

Re: Treat your machine/pcb/acrylic/laser shop professionally

Update: 9/25/2010 to http://openpcr.org/2010/07/treat-your-machine-shop-professionally/

Good comment from mo – spread the love around. I want to point out that the relationship with your machine/PCB/acrylic/wood shop can be challenging! It’s important but not necessarily easy!

If you can’t meet in person it’s tougher to build repertoire over email or telephone, no matter how charismatic you are. And though I’m usually close to my email, people in shops are on tools and machines most of the time. A phone call is a lot quicker and more personal, but conversations on the phone often lead to miscommunications and frustration. What’s worked for me is talking on the phone, and then summarizing in a follow-up email immediately afterwards. Other points of friction I’ve found are in file formats (I was in Bangalore, India, bouncing between coffee shops and I just couldn’t get the right program in order) and computer use  (for instance a shop that insists on printed 2D drawings of a nice 3D CAD file you struggled to put together…), and one guy that always returned calls around a week later.

Experience says: lavishly praise shops you come across when everything goes smoothly.

Right now: I’m working with a shop called OharaRP (out of Dayton, Ohio) on a PCB board and they kick ass!

Tito

Treat your machine shop professionally

While searching for machine shops — quoted from: http://www.omwcorp.com/how-to-design-machined-parts.html

If you want the best out of your machine shop, it’s important to treat them well. People like to do business with people they like, and it stands to reason that favorite customers get special attention. Here are a few do’s and don’ts regarding machine shop proprieties:

DO communicate regularly with your shop, call them if you perceive a problem. Don’t let problems simmer. Do work with them to resolve issues fairly. Cutting metal to high tolerances is an extremely difficult art, and some mistakes are bound to happen.

DO consult with your shop on design issues. Unless you’ve spent years of your life working as a machinist, don’t assume you know more about manufacturing issues than they do. Virtually all professional machinists have many years of training. Many have advanced degrees. Treat them as peers, not as subordinates.

DO pay your bills on time. Nearly all shops pay close attention to this. There is no question that fast paying customers get treated better.

DON’T use your shop as a free quoting service to scope out the cost of proposed projects. Quotes are expensive for a shop. Only request quotes for jobs the shop has a fair chance to getting. Don’t quote out jobs to more than 2 or 3 shops. Don’t expect a shop to continue to quote multiple jobs without winning some work.

DON’T try to beat a shop down on part costs. Do ask design advice on how part costs can be reduced. Treat your shop as part of your manufacturing team, and foster communication between design and manufacturing.

– PS, to the machine shops we’ve worked with already, thank you!

Update: 9/25/2010

A clarification. I want to point out that this element is important and it can be challenging to do! If you can’t meet in person, it’s tougher to build repertoire over email or telephone no matter how charismatic you are. And, though I’m usually close to my email, people in shops are on tools and machines most of the time. A phone call is a lot quicker and more personal, but conversations on the phone often lead to miscommunications and frustration. What’s worked for me is talking on the phone, and then summarizing in a follow-up email immediately afterwards. Other points of friction I’ve found are in file formats (I was in Bangalore, India, bouncing between coffee shops and I just couldn’t get the right program in order) and computer use  (for instance a shop that insists on 2D drawings of a nice CAD file you struggled to put together…).

Experience says: lavishly praise shops you come across when everything goes smoothly.

Right now: I’m working with an shop called OharaRP (out of Dayton, Ohio) on a PCB board and they kick ass!

Tito

Heat sinks arrived

All right, went and picked up the heatsinks at the UPS office last night. Broken them open while sitting in my car and made a couple quick judgments. Remember, my concerns are:

1. big enough surface area for the peltier
2. cost – $20 to $30
3. overall size and weight

The MassCool, while bigger in all dimensions, just isn’t big enough for the 4 cm square peltier. We would still need an aluminum plate adapter between the heat sink and the peltier.

The Titan on the other hand has the perfect sized surface for the 4 cm square peltier. It’s MASSIVE though.

I’m designing a quick prototype box today to send of to Ponoko. My focus is getting the case made to test out the heated lid. I’ve got a design using a spring hinge + thermal pads that I think will be easy to use and prevent condensation.

I’m also making the overall dimensions a lot bigger so they can fit any components we want to test out. Overall, it’s going to be 7″ tall, 7.25″ long, and 4.7″ wide. Our original case was and 5.7″ tall, 6.7″ long, and 5.4″ wide so this is test is quite a bit bigger. I’m going to test this out with both wood and acrylic, using a bolt design (the same one as the Makerbot) instead of glue. Glue is best for permanent slick looks, but since we’re  this is a hackable kit, bolts are easier to take on and off.

I’m also adding:

  1. Enlarging the hole for the aluminum block (4 cm square) to 4.4 cm square, to accommodate a layer of insulation around the block.
  2. Power port for the MicroATX ATX
  3. Front vents for the MicroATX so that we can test it internally

Make it hot

A good discussion on the OpenPCR heated lid over at O’Reilly Answers:
http://answers.oreilly.com/topic/1641-silicone-heaters-for-openpcr/page__p__3131&#entry3131

We’ve been thinking a lot about the heated lid, and have had some great ideas suggested.
Windell Oskay from Evil Mad Scientist Labs suggested actually making a custom PCB printed with copper trace to form a heater. What an awesome idea, definitely want to try it out.

I also found this great “wire making” tip on the EMSL site, looks good for fixing the ‘rats nest’ of wires we run into from time to time and thought I would share: link

Tonight Josh tried out a simple $16 peltier to do our heating and it worked, so we’ll go with that for now and focus on getting the mechanical design down. The heated lid must make flat contact with all the tubes, so a double hinged lid and some sort of downward pressure (magnets? latch?) are needed.

Tito